Friday 30 December 2011

A study of audiophile blind comparison and ABX testing

So, we love to have a good discussion/argument/rant on all the audio forums I have seen about the many claims audiophiles make that others dismiss as myths. The arguments go round in circles; I hear a difference - but there cannot be a difference, it is all in your mind - have you tried different cables? - I don’t need to it is all in your mind etc etc, we all know how it goes.

Then there are the debates that involved blind testing and ABX. They get so hot under the collar and circular that many forums have baneed them outright.

Occasionally there are attempts to run proper tests. WHF’s own Big Question is an example. Three What Hifi forum members are invited to their listening rooms and have been blind tested on cables to bit rates. From the issues I have read, there is a confirmation that the myths of differences are not correct, the differences are real. Different bit rates have been correctly identified, different cables have produced different sounds in the same Hifi kit. But, they are blind listening reviews, which are different from ABX tests where people are asked to correctly identify products.

Here is a list of blind listening and ABX tests that I have found on the internet. What I have done is summarise their conclusions.

It is important to note the difference between blind and ABX testing as they produce different results.

Blind tests mean the listener does not know what they are listening and are asked to describe any differences they can hear which is a type of blind testing commonly used in audio. That kind of test often results in low priced hifi 'surprisingly' doing as well as high priced as factors such as image, product reputation is hidden from the listener. Some blind testing also invloves a competition betwen products were say two amps are pitched next to each other and the wimnner progresses to the next round. As you see I have been broad in the defenition of blind testing.

ABX testing more of a test. You listen to product A and product B and are then played X, which is either A or B and have to say which it is. There can be more than A and B as some tests invlove multiple cables. Then any differences have to be clearly audible, which for the likes of cables has not been the case yet.  I have also been broad in the definition of ABX testing.

The aim is to see what the overall result of these tests gives us and whether they provide evidence to back up or deny the reality of alleged audiophile myths. Before you read on here is a test you can try out yourself...

http://www.audiocheck.net/blindtests_index.php

...and here is a very interesting article on a debate between audio sceptic Arny Krueger and Stereophile editor John Atkinson on ABX testing

Stereophile The Great Debate

Finally, for those who say blind testing is designed to produce fails and discredit audiophiles, here are some positive ones where differences have been identified

http://www.head-fi.org/forum/thread/513481/are-blind-tests-bogus-examples-of-blind-tests-with-positive-results


1 - ABX Double Blind Comparator.

This is a web site dedicated to such testing. Back in May of 1977 there was a comparison of amplifiers which found over three tests of two amps each, listeners could tell a difference in two, but not the third which was an even split. It is important to note that not all of the ABX tests here are negative. Some do find differences can be identified. That shows that with some parts of the hifi chain there are real differences, but with others there are not.

ABX Double Blind Comparator Data

A test of interconnects and speaker cables found that no one could pick out the differences between a series of wires from ‘blister pack $2.50 to $990 speaker cable. All the results were even with approximately 50% going for the cheap and expensive options.

There is an interesting comparison of ‘video cables’ which found that once over 50 feet it was easy to spot which was the 6 foot cable and the much longer one.

DACs don’t fair well with CDPs finding an original CDP being distinguishable from a more modern one, but an expensive stand alone DAC being the same as a CDP.

None of the tests involve a large amount of people and some are just of one person.

2 - Effects of Cable, Loudspeaker and amplifier interactions, an engineering paper from 1991.

http://www.apiguide.net/04actu/04mus...teractions.pdf

Twelve cables are tested from Levinson to Kimber and including car jump leads and lamp cable, from $2 to $419 per metre. The results are based on the theory that loudspeaker cable should transmit all frequencies, unscathed to any speaker from any amplifier and loss is due to resistance. There is an assumption that letting through more frequencies with less distortion will sound better. But that seems reasonable to me.


The best performance was with multi core cables. The car jump leads did not do well and cable intended for digital transmission did! The most expensive cable does not get a mention in the conclusions, but the cheapest is praised for its performance and Kimber does well. Sadly there is not a definitive list of the cost of the cables and their performance, so it is not clear as to whether cost equals performance, but the suggestion is that construction equals performance.


3 - Do all amplifiers sound the same? Original Stereo Review blind test.

http://www.bruce.coppola.name/audio/Amp_Sound.pdf

(If that link does not work, this one is a descrptive of what happened)

http://www.hometheaterfocus.com/receivers/amplifier-sound-quality.aspx

A number of amplifiers across various price points and types are tested. The listeners are self declared believers and sceptics as to whether audiophile claims are true or not.

There were 13 sessions with different numbers of listeners each time. The difference between sceptic and believer performance was small, with 2 sceptics getting the highest correct score and 1 believer getting the lowest. The overall average was 50.5% getting it right, so that is the same as you would expect from a random guess result. The cheapest Pioneer amp was perfectly capable of outperforming the more expensive amps and it was ‘striking similar to the Levinson‘.

As an extra to this and for an explanation of how amps can all sound the same, here is a Wikipedia entry on Bob Carver and his blind test amp challenges

http://en.wikipedia.org/wiki/Bob_Carver#Amplifier_modeling


4 - Cable directionality.

Not the best link as it only refers to a test without giving too many specifics. The cable maker Belden conducted a test with an un named magazine which found the result was perfectly random.

I liked the next sentence which was “Belden is still happy to manufacture and sell directional cables to enthusiasts”

The Truth About Audio and Other Cables - AES PNW Section Meeting Report -


5 - Head - Fi ABX Cable Taste Test Aug 2006.

Three cables from Canare, Radio Shack and a silver one were put into the same sleeving to disguise them, a mark put on each one so only the originator knew which was which and then sent around various forum members. The result was that only one forum member got all three correct. The Radio Shack cheap cable and the silver were the most mixed up.

Unfortunately I cannot see from the thread, which is huge how many members took part and what the exact results were.


6 - HiFi Wigwam, The Great Cable debate. Power cable ABX test Oct 2005.

This is a very well done large scale ABX test. A similar set up to Head-fi where four mains cables including 2 kettle leads (stock power cords that had come with hifi products), an audiophile one, a DIY one and a tester CD were sent out forum members. The results were inconclusive to say the least, for example;

The kettle lead was C. There were 23 answers :
4 said that the kettle lead was A
6 said that it was B
8 said that it was C
5 said that they didn't know.

http://www.hifiwigwam.com/showthread.php?654-The-Great-Cable-Debate&highlight=blind+test

The overall conclusion was that the kettle lead could not be properly identified or that one cable was better than another.

EDIT - one of the participants to this test has pointed out that the two kettle leads, described in the test as exactly the same were in fact not identical and were just basic leads which had come with hifi products.


7 - What Hifi The Big Question on cables. Sept 2009

From the Sept 2009 issue. Three forum members were invited to WHF and blind tested where they though the kit (Roksan, Cyrus, Spendor) was being changed, but instead the cables were. The same three tracks were used throughout.

The kit started out with the cheapest cables WHF could find and no one liked it saying it sounded flat and dull. Then a Lindy mains conditioner and Copperline Alpha power cords were introduced and the sound improved.

The IC was changed to some Atlas Equators and two out the three tracks were said to have improved with better bass and detail.

Last the 60p per metre speaker cable was changed for £6 per metre Chord Carnival Sliverscreen. Again, changes were noticed, but they were not big.

Various swaps took place after that which confirmed the above, that the power cords made the biggest difference. When the test was revealed the participants were surprised to say the least!

But, this is not an ABX test, it is a blind listening review and as you read on you find the two produce different results.


8 - Secrets of Home Theatre and High Fidelity. Can We Hear Differences Between A/C Power Cords? An ABX Blind Test. December, 2004

A comprehensive article with pictures and the overall result was 73 out of 149 tests so 49% accuracy, the same as chance.

http://www.hometheaterhifi.com/volum...s-12-2004.html


feature-blind-test-power-cords-manny-introduction.jpg



9 - Boston Audio Society, an ABX test of Ivor Tiefenbrun, the founder of Linn. August 1984


A rather complex testing of Ivor Tiefenbrun himself, who at that time was very pro vinyl and anti digital (the opposite almost of how Linn operate now!). There are various different tests and the overall conclusion was

"In summary, then, no evidence was provided by Tiefenbrun during this series of tests that indicates ability to identify reliably:
(a) the presence of an undriven transducer in the room,
(b) the presence of the Sony PCM-F1 digital processor in the audio chain, or
(c) the presence of the relay contacts of the A/B/X switchbox in the circuit."

http://www.bostonaudiosociety.org/bas_speaker/abx_testing2.htm

Even the founder of Linn could not back up claims he had been making when subjected to an ABX test of those claims.

10 - The (In)famous Audioholics forum post, cables vs coathanger!. June 2004

http://forums.audioholics.com/forums/showpost.php?s=97d4a3c39d247bf955a57b3953326a34&p=15412&postcount=28

11 - Matrixhifi.com from Spain. ABX test of two systems. June 2006.

Two systems, one cheap (A)  with a Sony DVD and Behringer amp (supported on a folding chair) with chepo cables and the other more expensive (B) with Classe, YBA, Wadia and expensive cables and proper stands were hidden behind a sheet and wired to the same speakers.

ppecTD.gif


The results were;
38 persons participated on this test
14 chose the "A" system as the best sounding one
10 chose the "B" system as the best sounding one
14 were not able to hear differences or didn't choose any as the best.

http://www.matrixhifi.com/ENG_contenedor_ppec.htm


12 - AVReview. Blind cable test. April 2008

Some of AVR's forum members attended at a Sevenoaks hifi shop and listened to the same kit with two cheap Maplins cables at £2 and £8 and a Chord Signature at £500. They found the cheaper Maplins cable easy to differentiate  and the more expensive harder to differentiate from the Chord. Their resident sceptic agreed he could hear differences. The final conclusion was;

....from our sample of 20 near-individual tests, we got 14 correct answers. That works out at 70 per cent correct....

So that is the second ABX to join What Hifi which suggests there is indeed a difference. But like What Hiif it shows the difference in results from Blind to ABX testing and how easy it is to try and obscure the two types of test.

http://www.avreview.co.uk/news/article/mps/uan/1863#ixzz0nGpGRfCB

13 - Journal of the Audio Engineering Society, ABX test of CD/SACD/DVD-A. Sept 2007

You need to be a member of the AES to access the article here; (EDIT, the link has changed and I cannot find the actual test referred to)

http://www.aes.org/journal/online/JAES_V55/9/

a summary of which states "A carefully controlled double-blind test with many experienced listeners showed no ability to hear any differences between formats".  The results were that 60 listeners over 554 trials couldn’t hear any differences between CD, SACD, and 96/24.

EDIT - this test is apprently flawed, but basically the hi rez example used was from an original CD. Whether that is a flaw or not is open to further discussion.


14 - What Hifi, Blind Test of HDMI cables, July 2010

Another What Hifi test of three forum members who are unaware that the change being made is with three HDMI cables. As far as they know equipment could be being changed. The cables are a freebie, a Chord costing £75 and a QED costing £150. Throughout the test all three struggle to find any difference, but are more confident that there is a difference in the sound rather than the picture. They preferred the freebie cable over the Chord one and found it to be as good as the most expensive QED. That result is common in blind testing and really differenentiates it from ABX tests.



15 - Floyd Toole from Harman International (AKG, Infinity, JBL) Audio, Science in the service of art 1998

A paper written by Floyd Toole which covers a number of topics about scientific measurements and audio. Go to pages 6 and 7 and there is a paragraph on blind testing. It shows how the 'differences' between speakers were greater when sighted tests were used over blind tests. The obvious conclusion is that sighted tests result in factors other than sound come into play when deciding on what sounds better.

http://www.harmanaudio.com/pv_obj_cache/pv_obj_id_7A7EB027F9D3A7B68272375CB10EFDC694000200/filename/audio_art_science.pdf


16 - Sean Olive, Director of Acoustic Research Harman Int, blog on The Dishonesty of Sighted Listening Tests 2009

http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

Research using 40 Harman employees and comparing the results of blind vs sighted tests of four loudspeakers. As with the above by fellow Harman director, sighted tests show bias that blind do not.

Below the article are various responses to the blog, including a very interesting exchange between Alan Sircom, editor of Hifi Plus magazine and Sean Olive. Alan Sircom makes the very interesting point that volume has a role to play with blind tests

"Here's an interesting test to explain what I mean: run a blind test a group of products under level-matched conditions. Then run the same test (still blind), allowing the users to set the volume to their own personal taste for each loudspeaker under test. From my (admittedly dated and anecdotal) testing on this, the level-matched group will go for the one with the flattest frequency response, as will those who turn the volume 'down', but those who turn the dial the other way often choose the loudspeaker with the biggest peak at around 1kHz, saying how 'dynamic' it sounds."

I had not thought of that before. You will end up with different conclusions between a blind test where the volume is set and where the volume can be adjusted. Adjustment allows preferences for different sounds to be expressed, without other influences being present that clearly have nothing to do with sound.

17. Russ Andrews re-cable David Gilmour's recording studio (not a blind test) 2000-2001

This is not a blind test, but I think it is worth including here. The studio used (and I think owned) by David Gilmour was re-cabled using Kimber cables by Russ Andrews. This was apparently after extensive AB testing. I would have loved that to be after extensive ABX testing!

http://www.russandrews.com/viewindex.asp?article_id=astoria&src=blog

(Thanks to Pio2001 for finding the below tests and links)

18. DIY Audio forum, confessions of a poster. 2003

A forum member joined and confessed that " Then I started to hear about some convincing blind tests and finally conducted my own. I was stunned at the results. I couldn't tell a $300 amp from a $3000 in the store I was working at. Neither could anyone else who worked there." Then he did his own blind test on a mate between an Onkyo SR500 Dolby Digital receiver and a Bryston 4B 300 wpc power amp and a Bryston 2 channel pre-amp owned by his mate. The 'red faced' mate could not tell the difference.

http://www.diyaudio.com/forums/solid-state/12752-blind-listening-tests-amplifiers.html

19. The Boston Audio Society, discussion of two blind tests and their analysis 1990

The BAS in an article discussing a CD tweek blind test by Stereophile; " In the CD-tweak test Atkinson and Hammond conducted a 3222-trial single-blind listening experiment to determine whether CD tweaks (green ink, Armor-All, expensive transports) altered the sound of compact-disc playback. Subjects overall were able to identify tweaked vs untweaked CDs only 48.3% of the time, and the proportion that scored highly (five, six, or seven out of seven trials--Stereophile's definition of a keen-eared listener) was well within the range to be expected if subjects had been merely guessing."

Then the BAS are very critical of a Hifi News analysis of a blind test of amps from 2006; " Listeners scored 63.3% correct during those trials where the amplifiers were different (95 of the 150 A-BB-A trials). However, subjects scored correctly only 65% of the time when the amplifiers were the same (26 of 40 A-A/B-B trials.) Another way of saying this is that subjects reported a difference 35% of the time (14/40 trials) when there could have been no difference."

http://www.bostonaudiosociety.org/bas_speaker/wishful_thinking.htm

20. Cowan Audio, an Australian audiophile and a blind test between CD players 1997

A $1800 un named (they were reluctant to name it) versus a $300 Sony which resulted in both only guessing and getting about 50%. William Cowan stated that a sighted test before hand made them say "This will be easy, lets get on with the blind test". Ooops!

http://www.cowanaudio.com/

21. Pio2001's own ABX test between CD and vinyl in Hydrogenaudio 2003

The results were 3/7 and 5/8 correct.

http://www.hydrogenaudio.org/forums/index.php?act=ST&f=21&t=7953

22. Tom Nousaine, article to Tweak or not to tweak? 1988.

A test of identical CDP and speakers but different amps and cables, one being $300 and the other $5000. The results with 7 listeners of varying interest in hifi and 10 trials was a fail.

http://www.nousaine.com/pdfs/To%20Tweak%20or%20Not.pdf

23. AV Science Forum, Monster vs Opus cables. 2002

Not particularly rigorous as in there were not enough tests, but as the poster states "And to cut to the chase, Mike could not identify the Monster from the Opus MM with any accuracy (nor the reverse, which also would have been a positive result if he had been consistently wrong) using our testing methodology. We stopped the test a little less than halfway through, I think we got through 8 A/Bs before we gave up."

http://www.avsforum.com/avs-vb/showthread.php?t=941184

24. Stereo.net, blind testing of two pre-amps April 2008

Its an Australian forum so the conclusion is typically forthright "CONCLUSION:There is bugger all between the 2 preamps, they were so close that any difference could not be reliably picked." The test was run well despite what doubts the tester has.

http://www.stereo.net.au/forums/showthread.php/26875-Blind-Testing-Report-Lightspeed-vs-ME24-preamps

25. Stereomojo Digital amp shootout 2007

Various amps were tested blind, in pairs where the preferred amp went through to the next round. The winner was one of the cheaper amps called the Trends Audio TA-10 at $130, which is the tiny one on the top right of the pile

clip_image012_006.jpg

http://www.stereomojo.com/SHOOTOUT2007INTEGRATEDS.htm

26. Head-Fi ABX Cable Test by member Edwood Aug 2006

Three ICs made with Canare, Solid Silver and Rat Shack cables, but dressed to look the same. Only one person could tell the difference, which you would expect to happen when there is no audible difference and people are most likely guessing.

http://www.head-fi.org/forum/thread/190566/blind-cable-taste-test-results

27. Les Numeriques. A blind test of HDMI cables by a French site (Google Translator used)

Nine participants using no name, Belkin and Monster HDMI cables. Only one claimed to have a preference, but his feedback was inconsistent.

http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=fr&tl=en&u=http%3A%2F%2Fwww.lesnumeriques.com%2Fblind-tests-avec-deux-jurys-experts-et-lecteurs-p770_6175_93.html


28. Home Cinema Fr .Com, a French test of interconnects (Google Translator used) May 2005

The cables included ones from Taralabs, VDH, Audioquest and DIY ones. The result was that no one could reliably tell a difference.

PICT0219S.jpg

http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=fr&tl=en&u=http%3A%2F%2Fwww.homecinema-fr.com%2Fforum%2Fviewtopic.php%3Ft%3D29781210

29. Sound & Vision. Article by Tom Nousaine with 3 Blind Tests of speaker cables. c1995

http://www.nousaine.com/pdfs/Wired%20Wisdom.pdf

All three are fails by the listeners using their own hifi systems and with their choice of track, volume and time.

30. Insane About Sound, Blind Tests of CD vs Audio Files and expensive vs cheap speaker cable. Wall Street Journal Jan 2008

http://online.wsj.com/article/SB120044692027492991.html.html?mod=technology_main_promo_left

Tests set up at an audio show in Las Vegas, found Wav files (52%) doing better than MP3 (33%) when compared with CD and in a test of $2000 Sigma speaker cables vs hardwear store cable 61% of the 39 who took the test preferred the more expensive cable. So nothing conclusive for any of the tests, but interestingly John Atkinson and Michael Fremer from Sterophile magazine were described as easily picking out the more expensive cable.

31. AV Science forum, Observations of a controlled cable test Nov 2007

A blind test between Monster cables and Opus MM, which as far as I can find is $33,000 worth of cable

http://www.avsforum.com/avs-vb/showthread.php?t=941184

but the owner of the very high end kit and cables was unable to tell the difference.

32. The Audio Critic, ABX test of amps Spring 1997

A letter by Tom Nousaine to The Audio Critic in which he describes an ABX test of the owner of a very high end system, where a Pass Labs Aleph 1.2 200w mono block amp was randomly changed with a Yamaha AX-700 100w integrated amp. In the first test the owner got 3 out of 10 identified, then 5 out of 10. His wife then got 9 out of 16 and a friend 4 out of 10 correctly identified.

The letter is split between pages 6 and 7 of the link.

http://www.theaudiocritic.com/back_issues/The_Audio_Critic_24_r.pdf


33. Expert Reviews. Blind test of HDMI cables. Expert reviews 8 Feb 2011

Two TVs, two Sony PS3s and a James Bond film played side by side with the only variable being changed HDMI cables. What is interesting is that there was little difference with the picture, but much more perceived difference with the sound. But, as many preferred the sound of the cheap to the expensive cables.

http://www.expertreviews.co.uk/home-entertainment/1282699/hdmi-investigated-are-expensive-cables-a-scam/4

Note - not an ABX test and the reviewer acknowledges there could also be slight differences in the TVs and PS3s to contend with.

34. Blind test of six DACs, Stereomojo

Like the other blind as opposed to ABX tests this one found the cheapest and most expensive DAC in the final, with only a hairs width between the two in terms of sound.

http://www.stereomojo.com/Stereomojo%20Six%20DAC%20Shootout.htm/StereomojoSixDACShootout.htm

panel1.png


35. The Wilson ipod experiment CES 2004. Stereophile Jan 2004

Tenth paragraph down. A 'trick' blind test where a group at a consumer technology tradeshow thought they were listening to a $20,000 CDP, but were actually, happily listening to an ipod and uncompressed WAV files.

http://www.stereophile.com/news/011004ces/

Sight really does have a major role to play in sound!

36. An evening spent comparing Nordost ICs and speaker cables. AVForums June 2006

Further to the above ipod experiment, a report from a member of the AVForums and his experience of sighted and blind listening tests at a dealers.

http://www.avforums.com/forums/interconnects-speaker-cables-switches/351773-evening-comparing-nordost-interconnects-speaker-cable.html

The conclusion comparing the tests

"And here's what I heard.

1. All the cables sounded subtly different with one exception.
2. Differences were less apparent with some music than others
3. My assessment and experiences "blind" were different to my experiences "sighted""


37. A blind test of old and new violins. Westerlunds Violinverkstand AB March 2006

This is really a bit of fun, but it again shows how we hear differently sighted to blind. In this test 6 violins, three c1700 (including a Stradivari) and three modern were played to a group of string teachers who cast votes 1 to 3 on their preferred violin. The stage was kept dark and they could not see which was which. The Stradivari came last, a modern brand won.

http://www.westerlunds.se/blindtesteng.htm


38. The Edge of audibility, blind test of recordings made with and without a mains filter. Pink Fish Media forum June 2011

You can download and try the recordings yourself. Of those who have already, 2 preferred one, 6 the other and 10 had no preference.

http://www.pinkfishmedia.net/forum/showthread.php?t=101683

39. Try a blind test of bit rates. mp3ornot.com

A really well set out and easy to use bind test of different bit rates.

http://mp3ornot.com/


40. Blind test of CD transports Stereo.net.au Oct 2008

Well set up and described, but to reinforce the Australian stereotype, after one set of failed tests they admitted no one could hear a difference, gave up and drank some beers instead!

http://www.stereo.net.au/forums/showthread.php/10141-Blind-Test-GTG-1-CD-Digital-Transports

EDIT - link presently broken

41. ABX test of tracks with various levels of jitter added. HDD Audio forum March/April 2009

http://hddaudio.net/viewtopic.php?id=15

http://hddaudio.net/viewtopic.php?id=63

One member, MM has recorded his scores and they are no better than random.


42. Stereophile ABX test of power amps July 1997

http://www.stereophile.com/features/113/index.html

There were 505 listeners producing the following nicely made graph of results

blindfig2.jpg

which is a bell curve around random, just as you get from guessing. Yet Stereophile claim there was success with test as some people did better than average. There could be some truth in that as there have been blind test passes for amps. Even so it is a very small part of those tested who really need to tested again to confirm whether or not they were just lucky. The test is not statistically significant enough to say there is an audible difference.

43. Head-fi. A forum member testing cables sighted and blind Nov 2011

http://www.head-fi.org/t/578621/cables-tested-with-results

This provides yet more evidence that sighted and blind testing produces consistently different results whereby people can hear a difference when sighted and cannot when listening blind.


44. Audio Society of Minnesota. Speaker cable listening test. April 2012

https://sites.google.com/site/audiosocietyofminnesota/Home/april-2012-speaker-cable-listening-test 

The results are very mixed with no cable making any clear difference. They accept there is no objective difference, but since there is a difference found which can easily be explained by random selection, they conclude a subjective difference is there and so allegedly "cable do make a difference".


45. The Richard Clark Amplifier Challenge - Reported by Tom Morrow june 2006


"The Richard Clark Amp Challenge is a listening test intended to show that as long as a modern audio amplifier is operated within its linear range (below clipping), the differences between amps are inaudible to the human ear."

It is an ABX test which to pass needs two sets of 12 correct identifications. Reputedly over a thousand have taken the test and none have passed.

"Do the results indicate I should buy the cheapest amp?


No. You should buy the best amplifier for your purpose. Some of the factors to consider are: reliability, build quality, cooling performance, flexibility, quality of mechanical connections, reputation of manufacturer, special features, size, weight, aesthetics, and cost. Buying the cheapest amplifier will likely get you an unreliable amplifier that is difficult to use and might not have the needed features. The only factor that this test indicates you can ignore is sound quality below clipping."

Which is a relief for those who have shelled out a lot on a nice amp.


46. Audio Video Revolution Forum, thread on blind speaker tests, Nov 2007.



Positive results which strongly suggest speakers are clearly different even under blind testing conditions, both objectively and subjectively.


47. PSB Speakers, blind comparison test of four speakers, Nov 2005.





http://www.psbspeakers.com/articles/Birthplace-of-Good-Sound

The writer is happy he did not pick out the cheapo speaker, but he makes no mention of whether or not the speakers were easily identified as different or not.


48. Audio Society of Minnesota, speaker cable test, April 2012



Random results from blind comparison testing of four cables, cable B being the expensive one at $8000. Each cable was pitted against another and preferences or not noted. The results were that cable B won one and lost two of the tests. The cheapest cable lost all three tests, so the author makes a spurious claim to there being subjective preferences, which is OK, but would you spend $8000 on a cable based on such a result?


48. Which? Consumer magazine, 2016

The UK consumer magazine, which values its independence and testing procedures to give fair and independent advice.
"Which? testing has shown that cheap HDMI leads - even value ones costing just a few pounds - can perform just as well as more expensive ones. When we last ran HDMI tests, we found that a £10 HDMI lead from a supermarket gave no discernible difference in picture quality to one costing almost £100."

Read more: http://www.which.co.uk/reviews/televisions/article/buyers-guide-to-hdmi-cables - Which?
49. Trust Me I'm a Scientist - Audio Poll: Neil Young and High-Definition Sound, May 2012

A bind test of a high def WAV file version of Neil Young's self titled debut album against some standard AAC files.

"The majority of you are audio engineers, professional musicians, and ambitious hobbyists, and I figured that if anyone would be able to tell these file types apart, it would be you guys.
So, how did you do?
Well… please accept my warm congratulations to the 49% of you who guessed right.
That’s right: even among our readers, the results came out no better than a coin flip. And we didn’t even need a huge sample size to get a result that’s consistent with the tremendous mountains of research already done in this field."


Conclusion


The clear conclusion is that ABX testing does not back up many audiophile claims, so they become audiophile myths as they show cables do not inherently change sound. Any change in sound quality comes from the listeners mind and interaction between their senses. What is claimed to be audible is not reliably so. Blind testing is also sometimes passed off as ABX. But blind testing is not really testing, it is a review of a product without seeing it, and that allows claims to be made about sound which have not been verified.

If hifi is all about sound and more specifically sound quality, then we should, once the other senses have been removed be able to hear differences which can be verified by being able to identify one product from another by only listening. But time and again we cannot.

So you can either buy good but inexpensive hifi products such as cables, amps, CDPs and be satisfied that the sound they produce is superb. You do need to spend time with speakers as they really do sound identifiably different. Or you can buy expensive hifi products such as cable tec and luxuriate in the build and image and identify one hifi from another by looks and sound. But you cannot buy expensive and identify it from cheap by sound alone. However and this is important,

http://www.audiostream.com/content/blind-testing-golden-ears-and-envy-oh-my#wsTQZ0dOJYDcJv5K.97

After failing a blind test, one hifi buff, no less the editor of Sterophile said

"Over 10 years ago, for example, I failed to distinguish a Quad 405 from a Naim NAP250 or a TVA tube amplifier in such a blind test organized by Martin Colloms. Convinced by these results of the validity in the Consumer Reports philosophy, I consequently sold my exotic and expensive Lecson power amplifier with which I had been very happy and bought a much cheaper Quad 405—the biggest mistake of my audiophile career!"
The author of the article goes on to say;
"My point being, taking part in any kind of blind listening test necessarily creates an unnatural condition, one that we never encounter when listening to music for pleasure."
I agree 100%, I did the same with my set up, reading and researching for this thread I would switch from using my Firestone Fubar DAC and power supply to using the DAC that comes in my MF X_CANV8P headphone amp. All the testing states they sound the same. But they don't!!!!! That is because when I listen for pleasure I can see my set up, its red, green and blue lights on telling me it is working. That gives me pleasure and pleasure makes for better SQ.


(Originally posted on the Head-fi forum)

Monday 26 December 2011

Speed kills

A favourite amongst safety campaigners, but often ridiculed by motorbike riders, particularly the sport bike riders is the simple phrase 'speed kills'.

Here are a few quotes from The Biker Forum

"What a load of crap, I can't believe any biker would come out with this sort of drivel - lack of control kills, not speed. Are any of the relevant authorities concentrating on that? Are they f*ck :rolleyes:"

"Whoever dreamed up the statement "speed kills" wants hanging. Its the sudden stop that kills"

"Speed does not kill and we only have speed cameras because we have a daft road safety policy based on the misconception that speed kills"

"I'm not advocating driving like an idiot (the road is NOT a racetrack), but the idea that speed and ONLY speed kills is the preserve of the deluded"


There is clearly a complete failure to understand what happens in a road crash/accident whatever you want to call it. Accidents are made up of three parts

CAUSE

Inattention is the most common cause of an accident, or as the law puts it, driving "without due care and attention"

http://www.legislation.gov.uk/ukpga/1988/52/section/3

Not looking properly, failing to take into consideration road conditions or the amount of traffic and losing concentration make up the bulk of causes. The biggest single type is known as right of way accident where basically two vehicles want to be on the same bit of road at the same time. That is followed by loss of control on bends and overtaking or filtering.

http://mile-muncher.co.uk/dft_rdsafety_035422.pdf

However, excessive speed for the conditions removes some of the chance you have to avoid the collision in the first place.This can affect any compensation claim resulting from an accident

http://www.motorcyclecompensation.co.uk/Speed.aspx

Here is one of the examples show by the compensation website

A motorbike overtaking at excessive speed hits a car doing a u turn. The biker was held to 100% responsible as his speed meant he had ignored how his speed affects his ability to avoid potential hazards.


TYPE

Examples of the type of accident are rear end collison, side impact and loss of traction causing a fall or skid


SEVERITY

This is the part that those who say speed does not kill have failed to grasp. It does not matter what the cause or type of accident that you have, the severity and survivability of the accident is determined by the speed at the point of impact, or as one biker put it, the sudden stop that kills.

From a Norwegian study in 2004 on speed and accidents

http://www.trg.dk/elvik/740-2004.pdf

"The main findings of the research presented in this report can be summarised as
follows:

1. There is a strong statistical relationship between speed and road safety. When the mean speed of traffic is reduced, the number of accidents and the severity of injuries will almost always go down. When the mean speed of traffic increases, the number of accidents and the severity of injuries will usually increase.

2. The relationship between changes in speed and changes in road safety holds for all speeds in the range between about 25 km/h and about 120km/h.

3. The relationship between changes in speed and changes in road safety can be adequately described in terms of a power model, in which the relative change in the number of accidents or accident victims is a function of the relative change in the mean speed of traffic, raised to an exponent. The
following exponents summarise the effects of changes in speed:
a. Fatalities: 4.5
b. Fatal accidents: 3.6
c. Seriously injured road users: 3.0
d. Serious injury accidents: 2.4
e. Slightly injured road users: 1.5
f. Slight injury accidents: 1.2
g. Injured road users (severity unspecified): 2.7
h. Injury accidents (severity unspecified): 2.0
i. Property-damage-only accidents : 1.0

4. Several other mathematical functions may describe the relationship between speed and road safety, but the generality and simplicity of the power model makes it superior to other models. The model is, however,
not necessarily valid outside the range of speeds found in the present study (from about 25 km/h to about 120 km/h).

5. The relationship between speed and road safety is causal and can be explained in terms of elementary laws of physics and biomechanics. Speed is clearly a very important risk factor with respect to both accident
occurrence and injury severity."

Anyone with a basic knowledge of physics and some common sense will understand that kinetic energy transfer at the point of impact and its effect on the human body is what causes injuries. The higher the speed, the more kinetic energy there is flying around and the more severe injuries are likely to be. (I accept there is such a thing as a lucky escape, but people can also die from very minor collisions).

CONCLUSION

Speed kills refers to the impact speed has on the severity of an accident which in turn determines survivability. The higher the speed the less survivable an accident will be. Speed also robs the rider of opportunities to avoid the accident as the situation develops. This superb safe driving commercial expalins that in terms even the daftest of biker should understand...



How do audiophile cables work Part 6 - conclusion

Audiophile cables do work to make different people's hifi systems sound different some of the time. The cause is not inherant in the cables itself, its construction or materials.

Instead, as much as many audiophiles hate the idea, cables affect sound quality only when they operate in conjuction with other senses, particulary sound. That is proven by the consistently different results obtained by sighted, blind comparison and ABX testing.

That is further corroborated by the differing reports on what cables sound like, a subjective issue in any case. If a specific type of cable had a specific linked effect which the majority could hear, we could say that there must be something within a cable which makes it sound objectively different. But even after 40 years of research nothing has been identified by any cable company.

Resistance may also play a part as resitance causes attenuation, attenuation affects volume and volume affects sound quality. But that will never sell cables as you can achieve the same effect with the volume control on your amp.

My advice would be to buy from the pro audio world which has not been affected by pseudoscience and myth and prices are far more reasonable. 


How do audiophile cables work? Part 5 - in the mind

Since we have established no electrical or construction cause for different cables producing different sound quality, we have to look at the other potential variable, the listener.

Cable believers howl when it is suggested that they are somehow hearing things or fooling themselves. But all of the very credible reports of cables sounding different (which includes myself) when sighted shows this is not the imagination at work. I believe it shows there is a strong link between the other senses and hearing and sound quality.

Here are some studies that link the senses


A study of contextual influences on sound quality evaluation
http://www.ingentaconnect.com/content/d … 6/art00005
"Product sound quality judgments are based on perception of both acoustical characteristics and various non-acoustical factors. This paper focuses on how non-acoustical, contextual, factors might impact sound quality evaluation. Three different experiments showed that a positive or negative attitude towards the product (induced by priming tasks, mood, or reading about others' opinions) systematically influenced how sounds were perceived. Moreover, temporary influences such as mood interacted with more stable individual differences such as noise sensitivity. These findings suggest that product sound quality evaluation is variant across people, and that both research and industry need to consider contextual factors to fully understand how the concept of quality is constructed."

A study into developments in sound quality evaluation
http://intellagence.eu.com/acoustics200 … /572-0.pdf
which studies all sorts of sounds including car doors shutting and snoring!  It states "the image of brand names or audio-visual interactions can significantly influence sound quality judgements"

A study of country of origin and brand and their influences.
http://www.wu.ac.at/werbung/download/pu … 97cems.pdf
It finds that identical CDPs were rated differently for sound quality depending on their supposed country of origin. (See page 43 of the report).


Sennheiser's annual report of 2010 has some interesting articles about the affect taste has on sound. Here is a description of a study by Heriot Watt University where volunteers tasted wine to different types of music and then described the taste. It was affected by the music.
http://www.sennheiser-annualreport.com/ … _ears.html


It seems reasonable that sight affects sound as well, which helps to explain why we get so many reports of items such as cables, which should not sound different, sounding different.



There has been very little testing of cables, but here is one where a psychology students tests cables and sound vs value

https://docs.google.com/present/view?id … Nkd2N0NmM2
where when the subjects know the value they can hear a difference, but when they are blinded they cannot hear a difference any more.
"For the past few weeks we have been learning about the brain and it's amazing properties, we decided it would be a perfect time to test the brains capability to alter reality.  Our minds after all are very powerful in the ability to deceive us.   We decided to perform an experiment that we have devised to determine if the whether cost of something really scales perfectly with the performance, or does the mind play a greater role in determining this.   If the latter is true, then, our mind's perceived value of equipment will increase the fidelity of what we hear when we listen to audio.  This would reinforce the concept that our minds are powerful enough to change even the way we hear based on factors other than reality. In order for us to test this experiment we gathered a group of volunteers with the promise of an experience they would not soon forget.  Our procedure is as follows: We setup a test platform consisting of an audio set up with changeable variables the first setup used cheap and easily obtainable stock cables, in the second set up we swapped these out for far more expensive cables.  The aim of our experiment was to test whether or not the perceived value of the setup changed the way the listener heard the sound.


How:   After that we blindfold the participants and repeat the listening experience but switching the cables randomly each time.  After the test subject has listened to music 4 times, we ask the order in which the cables were used.  After they explain to us what they think they have heard in order we tell them what the actual order is.  The target of our experiment was people who listened to music.  To collect the data from these individuals we had invited them over to a house with our equipment set up and allowed them to be comfortable and sat them down.  From there we had let them start our experiment. 


Our experiment was conducted by letting participants listen to both the cheap and expensive audio and then letting them make an analyses on what the sound quality is with both. After setting up the test station and gathering our test subjects, we began the test by first allowing the subjects to hear the cheap and the expensive cable separately. Each time we specifically told them which cable they were listening to. After a few tries, most subjects claimed that they were able to differentiate between the two. When the subjects were satisfied with what they heard, we blindfolded them and subjected them four random tests. Each one of the four consisted of either the expensive or the cheap set of cables. We did this randomly without sequence. After this, they explained to us what they thought they had heard in chronological order and then we told them what the actual order is.  All subjects we tested were unable to correctly identify between the cables despite having proclaimed a huge difference between the cables before the cable was put on. We did this for 12 participants including ourselves, we felt that we too were also viable candidates for the test, as bias was nearly impossible in this kind of test.  This was easily proven by the fact that even though we tested each other before conducting the experiment, our results matched those of our test subjects.


Results analysis: The participants could tell a difference in sound quality when the participants knew which audio cable we were using.  This had changed dramatically when we did not tell them what we were using and were blindfolded; none of the participants were able to tell the difference between the two cables consecutively.  These results tell us that the price of equipment affects our judgment due to the fact that our minds are powerful and that it can skew our judgment just by thinking that something is better than the other.  This would be due to the fact that our minds want to have a relation between both price and quality.  This might have to do with the fact that we do not want to be scammed into paying for something that is actually cheap.  In order for our minds to do this they will correct whatever we are missing or what we find is wrong.  A reason for this mental "safety net" could be to make us feel less regret when something bought that is expensive underwhelms us.  As these participants did not buy the equipment they might have subconsciously thought about how price will be matched linearly to quality thus altering what they think.


Due to the fact that before being blindfolded participants had stated they could tell a difference in sound quality between the two cables, most of which stated that the more expensive cable sounded better, we are able to conclude that our minds influence the way we hear things depending on the perceived value of what we listen to.  Therefore we can conclude that our hypothesis was correct and that perceived value really does change what we think is a better sound quality.  Some of the variables we may have missed though would be that our participants may have been subject to some type of hearing loss.  To prevent this, we would need to conduct this experiment on a larger scale then what we have previously tested.  Some other things that we can do is redo this test with a larger variety of cables.  This meaning that we could test new equipment to see if it really will make audio a better quality by using this same procedure.  Another thing that we could do is use the data to make things sound better to customers or the person receiving it by telling them that the equipment they are using is expensive.  This would revolutionize the way we see technology by learning that people will actively fix what our minds feel is missing.  This would mean that  doctors could prescribe "expensive" medication to amplify the effects of the medication being prescribed, a sort of "super" placebo effect. Our minds actively alters what the brain receives due to changes in expectations.  Despite it being only a minuscule or non-existent change it is amplified or created into something we perceive as a huge difference. Cognitively it can be said that does this due to expectation that have been set upon us.  We want to hear a difference because we expect a difference as a result of the price that we paid, therefore it can be argued that at times humans can easily be manipulated due to our expectation that value will scale linearly with performance. "




Saturday 17 December 2011

How do audiophile cables work? Part 4 - measurements

The main stance of the cable sceptic is that when you measure a cable there is no difference from one to another that can account for the reported sound quality differences. Cable believers reply that is not true, there are differences between cables and then refer to cable maker reports of how their cable is made differently and therefore sounds different. But in Part 2 it has been shown that is a non sequitur and cable makers cannot make a connection between how a cable is made, what it is made of and sound quality.


Cable believers and makers site potential differences caused by skin effect, jitter (for digital cables), copper purity, copper vs silver, braiding the cable, solid core, multiple strands, wire thickness (AWG), the type of sheething, the connector (gold vs nickel plating). But they ignore two factors that do have an affect on sound quality.


Cable length


Testing has found one definite measuement that has an effect on cables, length. That particulalry applies to digital cables where the likes of USB has a recommended maxiumu length. http://www.datapro.net/techinfo/usb_info.html


"The most aggravating limitation of USB is the length restriction. Because of the nature in which data is carried through the cable, USB has an accepted maximum length of 15 feet. Some devices, depending on power needs and data bandwidth, may be able to go beyond this, but there are no guarantees"


Testing of HDMI cables has found they start to fail as the length goes up


http://www.audioholics.com/education/cables/long-hdmi-cable-bench-tests/hdmi-cable-testing-results


There are less definitive answers to the length an analogue cable can go to, but as it can act as an ariel the longer it is the more shielding it should have and the thicker and stronger it should be. Pro audio often uses very long cable lengths and strength and shielding is important, more so than in a domestic hifi setting.


However, this is not so much a sound quality difference as much as either the cable works or it does not. So sound quality is reduced not buy 'poor bass' or 'splashy treble', but by crackles and drop outs.


Cable resistance


I am sure, but from my own experience as opposed to testing that cables can also be affected by resistance. There is science behind that experience, attenuation. The higher the resistance the greater the attenuation.


http://en.wikipedia.org/wiki/Attenuator_%28electronics%29


"A line-level attenuator in the preamp or a power attenuator after the power amplifier uses electrical resistance to reduce the amplitude of the signal that reaches the speaker, reducing the volume of the output."


Russ Andrews sell attenuators and attenuated cables and here is his explanation of how attenuation affects volume;


http://www.russandrews.com/viewindex.asp?lookup=0&region=UK&currency=GBP&article_id=attenuation&target=blank&customer_id=PAA1760123511590TLZQFWRZKRJCZLMP


Try this yourself if you are unsure of volume and sound quality. Turn your amp right down and at low volumes there will be a lack of dynmaics and detail. Then turn the volume up and you start to hear a sweet spot where the music sounds at its best. Depending on your amp and your own subjective preference that sweet spot size will vary, but it tends to be between 10 and 12 o'clock on the dial. As you go louder the fine detail disappears again and distortion and clipping starts to happen.


The ear can detect a difference from as little as 0.2db volume. From Head-fi and member Nick_Charles "I have 4 CD players and no two have the same output level  and I can DBT the loudest and quietest 14/14 , but when I level match nope !"




However, usually an audible difference in volume is higher than that " Subjectively, a 2-3 dB change in sound level is barely perceptible; if someone asks you to "turn up the volume a little," you will probably increase the sound by at least 3 dB."


http://www.silcom.com/~aludwig/EARS.htm#Top


Then from the same article, Fletcher Munsen Curves which show how the ear will hear two tones which are at the same sound pressure level as having different loudness. 


To me this all suggests that volume has a big influence on sound quality and any affect on volume will cause subjective reports of sound quality to vary. In any case sound quality is a subjective matter anyway.But you cannot market a cable by saying, it will make the volume rise slightly, so improving sound quality, as you can do the same thing by adjusting the volume control on your amp!


(Maybe we should demand better quality of volume controls instead of cables?)

How do audiophile cables work? Part 3 - blind testing

As I discussed in Part 1, blind vs sighted testing and the results of blind testing really gets many an audiophile riled. Many audiophiles plain dismiss blind testing as it shows when they cannot see what they are hearing they either struggle or fail to tell any difference.

A common view is that blind tests are flawed.

http://www.stereophile.com/features/113 -

" But when you have taken part in a number of these blind tests and experienced how two amplifiers you know from personal experience to sound extremely different can still fail to be identified under blind conditions, then perhaps an alternative hypothesis is called for: that the very procedure of a blind listening test can conceal small but real subjective differences" - John Atkinson. Stereophile


http://www.avguide.com/forums/blind-listening-tests-are-flawed-editorial

"The answer is that blind listening tests fundamentally distort the listening process and are worthless in determining the audibility of a certain phenomenon." - Robert Harley. The Absolute Sound.

The basis of the flaw argument is that what was clearly heard when sighted is no longer so when listening blind, so therefore the blind test is faulty. I think that there is an alternative explanation.

There are those who argue sighted tests are wrong as well. Many cable sceptics claim people cannot really be hearing a difference as blind tests find that there is none. I think that is also wrong and that there is an alternative explanation.

That explanation is touched upon in Sean Olive's blog on sighted vs blind testing  - Audio Musings, Sean Olive, Harman International

http://seanolive.blogspot.com/2009/04/dishonesty-of-sighted-audio-product.html

This is about speakers, but it shows the different results that you get with sighted and blind tests and I think that also applies to cables. Here are the results of the different tests







What that shows is when sighted people find bigger differences than when blind. It does not show that either sighted or blind tests are flawed. That in my opinion is an inaccurate conclusion. Instead of a mistake in either type of test what we see is a different result and we should then be asking why is that happening? Before that the same result happens with cables.

Sighted testing

There are hundreds if not thousands of sighted tests of audiophile cables on the Internet. Go onto any hifi forum or get a hifi magazine and you will find them. For example

http://www.whathifi.com/review/silver-high-breed-metaphor-2

"This new name interconnect, to us, is a lively listen with a wide sound. It's decent for the price, and the supple midrange and bass work well.
But it suffers from a vicious top end, while production subtleties are stampeded over by a lack of cohesion. To pep up a dull system, this might be ideal; those with treble heavy kit should steer well clear." - What Hifi on the Silver High Breed Metaphor 2 interconnect.

http://www.whathifi.com/review/audioquest-cinnamon-usb

"This well-made Audioquest cable has a solid feel to it. Our sample is the 1.5m; 0.75 and 3m versions are also available.
Pairing our Chord Chordette DAC with the Cinnamon, we found that the sound of our set-up gained smoothness and a sense of authority.
Our kit served up a sweet-sounding treble, and well-integrated midrange, while the bass was sure-footed with nice weight to its delivery.
We’d like to hear more zip in dynamics, and more subtlety with tricky timing, but this Audioquest is worth checking out." - What Hifi on the Audioquest Cinnamon USB cable.

But whilst cable sceptics and believers argue about whether cables affect sound quality, cable believers also argue amongst themselves about what is the best sounding cable. One person will report a bright treble and another a dull treble.One person will report a 'night and day' difference whereas another reports a subtle difference. Then some will say they can hear no difference at all.

Then the 'Golden Ears' and 'Better Kit' arguments start. Claims are made that if you cannot hear a differences then there is something wrong with your ears or the rest of your hifi is not good enough and has insufficient detail for the cable to work. I cannot find any proof to back either argument up, but I will not dismiss them, I will offer an alternative reason to what is happening.

Sighted testing has also resulted in a clam that cables made out of silver wire sounds brighter than copper. But there is so much inconsistency in the results of sighted testing. Indeed none of it can be considered objective at all. All sighted testing is based on personal experience and opinion.

In 2011 when What Hifi was challenged by a forum member MaxFlynn through the Press Complaints Commission that it was deceiving its readers by reviewing cables as they really do make a difference, the result was that the complaint was dismissed as What Hifi stated that all of its reviews were just subjective opinion.

I my opinion too many reviews, if not the vast majority are presented as if they are objective and such and such a cable is better sounding than others. If cables really did do what they claim to do then why are the results not consistent and why, as in Part 2 are cable makers not able to show how construction is connected to sound quality?




Blind Comparison testing

I think that many people mix up the different types of blind testing and so here I want to show how the different types of blind test yield different, but consistent results.

What Hifi have been running  a series of articles called The Big Question in the magazine where forum members are invited to the test centre and take part in a series of blind tests. These are the best examples of blind comparison tests I can find. The listeners are asked their opinions on what they hear and are aware switching is taking place, but they cannot see exactly what is happening.

What Hifi The Big Question on cables. Sept 2009

From the Sept 2009 issue. Three forum members were invited to WHF and blind tested where they though the kit (Roksan, Cyrus, Spendor) was being changed, but instead the cables were. The same three tracks were used throughout.

The kit started out with the cheapest cables WHF could find and no one liked it saying it sounded flat and dull. Then a Lindy mains conditioner and Copperline Alpha power cords were introduced and the sound improved. The IC was changed to some Atlas Equators and two out the three tracks were said to have improved with better bass and detail.

Last the 60p per metre speaker cable was changed for £6 per metre Chord Carnival Sliverscreen. Again, changes were noticed, but they were not big. Various swaps took place after that which confirmed the above, that the power cords made the biggest difference. When the test was revealed the participants were surprised to say the least!

What Hifi, Blind Test of HDMI cables, July 2010

Another What Hifi test of three forum members who are unaware that the change being made is with three HDMI cables. As far as they know equipment could be being changed. The cables are a freebie, a Chord costing £75 and a QED costing £150. Throughout the test all three struggle to find any difference, but are more confident that there is a difference in the sound rather than the picture. They preferred the freebie cable over the Chord one and found it to be as good as the most expensive QED.


An evening spent comparing Nordost ICs and speaker cables. AVForums June 2006

Further to the above ipod experiment, a report from a member of the AVForums and his experience of sighted and blind listening tests at a dealers.

http://www.avforums.com/forums/interconnects-speaker-cables-switches/351773-evening-comparing-nordost-interconnects-speaker-cable.html

The conclusion comparing the tests

"And here's what I heard.

1. All the cables sounded subtly different with one exception.
2. Differences were less apparent with some music than others
3. My assessment and experiences "blind" were different to my experiences "sighted""

What you have here is that there are still differences being reported, but they are not night and day anymore and cheap is as likely to do well as expensive. That is the same as when speakers were blind comparison tested at Harman International and the following DAC blind test at Stereo Mojo;


Like the other blind comparison as opposed to ABX tests this one found the cheapest and most expensive DAC in the final, with only a hairs width between the two in terms of sound.

http://www.stereomojo.com/Stereomojo%20Six%20DAC%20Shootout.htm/StereomojoSixDACShootout.htm

The 'night and day' differences have disappeared. This is consistent with all blind comparison tests that I can find.



ABX testing

There are numerous ABX tests of cables. Here are a few;


AV Science forum, Observations of a controlled cable test Nov 2007

A blind test between Monster cables and Opus MM, which as far as I can find is $33,000 worth of cable

http://www.avsforum.com/avs-vb/showthread.php?t=941184

but the owner of the very high end kit and cables was unable to tell the difference.


 Sound & Vision. Article by Tom Nousaine with 3 Blind Tests of speaker cables. c1995

http://www.nousaine.com/pdfs/Wired%20Wisdom.pdf

All three are fails by the listeners using their own hifi systems and with their choice of track, volume and time.



AV Science Forum, Monster vs Opus cables. 2002

Not particularly rigorous as in there were not enough tests, but as the poster states "And to cut to the chase, Mike could not identify the Monster from the Opus MM with any accuracy (nor the reverse, which also would have been a positive result if he had been consistently wrong) using our testing methodology. We stopped the test a little less than halfway through, I think we got through 8 A/Bs before we gave up."

http://www.avsforum.com/avs-vb/showthread.php?t=941184


 HiFi Wigwam, The Great Cable debate. Power cable ABX test Oct 2005.

This is a very well done large scale ABX test. A similar set up to Head-fi where four mains cables including 2 kettle leads (stock power cords that had come with hifi products), an audiophile one, a DIY one and a tester CD were sent out forum members. The results were inconclusive to say the least, for example;

The kettle lead was C. There were 23 answers :
4 said that the kettle lead was A
6 said that it was B
8 said that it was C
5 said that they didn't know.
 
http://www.hifiwigwam.com/showthread.php?654-The-Great-Cable-Debate&highlight=blind+test


Conclusion

There is a definite correlation between the type of test and the result. A sighted test finds the biggest differences, blind comparison reduces those differences and ABX testing finds no differences at all. So no one type of test is any better or more accurate than any other and no type of test is flawed as all produce consistent results. That is important  where figuring out how cables can sound different to some people some of the time.

How do audiophile cables work? Part 2 - the cable makers.

Cable makers and many of their customers state they can hear a difference in their cables. I say that they are correct as they can hear a difference in the cable. However, what causes that difference?

Here I argue it is not down to the cable itself, there is nothing inherent in a cable that changes sound.  What I will show by various examples is that cable makers are continually missing the link needed between how a cable is made and how that affects sound quality. Cable makers have failed to show a connection between their products and  not just sound quality but any audible difference at all.

Instead I will show that it is the hype, (by both cable makers and many of their customers) about cables working to change sound quality that causes some people to hear a difference. Hype about cables is a better explanation for hearing differences.

Cables come in all sorts of shapes and sizes. Much of that hype is to suggest new knowledge and R&D that has resulted in evidence cables do affect sound quality. However, what follows is a series of  non sequiturs. Even the basic argument of ‘cables are different, I can hear a difference in sound, therefore cables cause the difference in sound’ is clearly potentially flawed. But that is what cable makers rely upon.

The ability to harness and transmit electricity and turn it into something useful is just about the biggest and most influential scientific step taken by mankind. The likes of Benjamin Franklin, Alessandro Volta and Thomas Faraday were conducting experiments and learning how to harness the power of electricity in the 18th and 19th centuries. Various laws of electricity have been known for a good length of time, such as Ohms Law published first in 1827 and have not found to be flawed.

The electric power that we need to power our hifis was first distributed to houses in NY in 1882, though before that individual wealthy people had their own power supplies.  Since then with the likes of the  current war between AC and DC, experience of and knowledge about the transmission of electricity down a cable has increased dramatically.  (2) But we are still using the original discoveries of the 19th century as the basic principles of transmitting electricity down a cable, such skin effect first noted in 1883. (3 )

It was in the 1970s that the idea that cables could be used to improve the  sound quality of hifis. QED cables were founded in 1973 and state by 1978 their speaker cable was considered a serious Hifi component.  ( 4) Now that idea is common place.  There are numerous companies making and marketing cables. A lot of study has gone into the construction of these cables.

What is clear in the following is that cable makers are still using the knowledge that was first being found back in the 19th century. There have been no new discoveries about cables and their inherent properties.  It is instead hype.

What is also clear is that they can show different cable construction means differences when it comes to transmitting a signal. But the science runs out when it comes to showing whether those differences are audible or not and how cables can affect sound quality.

In 2008 Russ Andrews claimed and then backed up that claim by measurements that they could show reduced RFI by they way they made their cable. But, they could not link reduced RFI to a better sound, they could only suggest it. As such in 2011 they had to stop advertising their cables as improving sound quality by reducing RFI until they had more ‘robust substantiation’ (5)

Tara Labs have a paper on Constant Current Impedance Testing (CCZT) which shows that there is a measurable difference in differently made cables frequency response. They are not alone there, as such has been shown with various studies.  (6) There are measurable differences between cables. Tara Labs say that such differences ‘highlight’ the reason why cable sound different. They say the measurements correlate with what ‘we can hear’. and they can ‘reliably correlate the listening experience to the test bench experience’. But there is no evidence presented to back up how they directly link a difference in the cable to a difference in the sound, beyond they can hear it.  They introduce the part of the paper correlating the cable with what they hear simply as ‘the sound…‘.

In 1995 QED published their ‘Genesis Report’ on loudspeaker cable. (7)They comment on the mysticism and pseudo-science around claims about cables. As with Tara Labs, there is a lot of evidence presented to show how a cable can measure differently. Again , that is little doubt. However, there is the issue of linking construction to sound quality.

They put forward an argument that applies to many cables, not just their own that accurate and consistent sounding speaker cables will have low capacitance, inductance, resistance and dielectric losses. They state that certain factors are unlikely to be audible such as skin effect. They also say that blind testing has shown that listeners are unable to discriminate cable directionality. The actual test is not shown and they do not apply blind testing to anything else in their paper.  Why use blind listening in one part only, why not use it for all of the claims made by QED?

Chord Cables claim lots of links between cheap cables which come free and ‘destroy‘ the information conveyed by music and their own which allow you to ‘really hear and enjoy your music‘, but as for evidence, none. (8)

ALO cables are superior because they are ‘built by hand’ and they ‘use only the finest materials available’. That is hype about build quality which is then contradicted when they acknowledge the Jena Labs cables copper discolours over time, but that does not affect sound. Yet later they state copper oxide is detrimental to sound. (9)  So which one is it? They do not evidence any link to sound quality.

Cardas provide a history of the development of cables from the earliest telegraph systems.  By the 1970s, like QED, Cardas state cables were seen as a part of the Hifi chain and along with that came ‘the scream of nay sayers’ who had  managed to ‘lose the lesson of our ancestors’.  By 2000 the ‘overall depth of knowledge is now at a new level’.  That is not the case. I have shown what they are speaking of has been known about for decades or longer. Cardas say that the most important issue is conductor/dielectric transition time differential. But no evidence of how that works or how audible it is, is put forward.(10) Their use of the ‘Golden Ratio’ in cable design is not linked to any claims about audibility.  Their use of ‘ultra pure and homogeneous metals’ are supposedly proven to produce the best sound. But no proof is shown. (11) Instead it is hype about build quality. Overall there is a large section on Cardas’ insights into cables, but none contain evidence on how they make their cable is linked to better sound. (12)

Blue Jeans Cables have again gone down the route of showing how there are differences caused to a signal in the way a cable is made. (13)  But, again they cannot link that to audibility and only say
“It's fair to say that people differ greatly in their ability to tell the difference between cables or components.” Yes, that is fair, but it is also suggesting the link without evidencing it. (14)

Instead of evidence to show the link we get hype that build quality and differences in cables cause improvements in sound.

Something else lacking in all of the cable company’s claims is peer reviews. If you are going to present white papers, Genesis reports or even insights, a second opinion would be nice.

I have listened to Hifi’s with expensive audiophile cables, bought a few relatively expensive audiophile cables and at different times heard and not heard a difference between them. I have made my own cables, I have blind tested and in my own experience the above holds true. I also secretly hope that a cable company can one day find the missing link, the quality in a cable that makes it inherently and provably sound different to other cables. But at the moment there is none and I doubt that there ever will be.

EDIT - Further evidence of the lack of a link is here in a paper submitted for an electrical engineering degree at MIT http://dspace.mit.edu/bitstream/handle/1721.1/46225/41567257.pdf

(1) http://en.wikipedia.org/wiki/Electricity
(2) http://en.wikipedia.org/wiki/Electrical_engineering
(3 ) http://en.wikipedia.org/wiki/Skin_effect
(4) http://www.qed.co.uk/2/about.htm
(5)http://www.asa.org.uk/ASA-action/Adjudications/2011/1/Russ-Andrews-Accessories-Ltd/TF_ADJ_49597.aspx
(6) http://www.taralabs.com/images/stories/whitepapers/Constant-Current-Impedance-Testing.pdf
(7)http://www.qed.co.uk/qed-reports/the-genesis-report.htm#introduction
(8)http://www.chord.co.uk/news2.php?id=3
(9)http://aloaudio.com/cable-faq.html
(10)http://www.cardas.com/content.php?area=insights&content_id=54&pagestring=History+of+Audio+Cable
(11)http://www.cardas.com/content.php?area=insights&content_id=5&pagestring=Why+Cardas?
(12)http://www.cardas.com/content.php?area=insights
(13)http://www.bluejeanscable.com/articles/whatwiredoes.htm
(14)http://www.bluejeanscable.com/articles/doeswirematter.htm

(Original version posted on Head-fi forum)