June 16, 2010

Blind Test Results

Here are some results of various blind tests. I won't vouch that they were done correctly as I haven't scrutinised the methodology to that extent.

Results are organised into two groups - those that indicated a difference and those that didn't.

Please keep in mind two things. Firstly, a large sample size is needed for an accurate result and secondly, both individual and group results could be considered. Typical results show no more accuracy than random chance, but some individuals may be quite accurate.

Results showing no difference

David Clarke Amplifier comparison
Conducted by:
David Clarke
Components tested: 5 amplifiers including a low cost Pioneer Receiver and Audio labs tube amp
Number of participants: 25 with a similar number of "believers" and "skeptics"
Level matched? Yes
Number of tests: Refer writeup
Results posted: view here > (PDF file)

Comments:
This test was conducted by respected Engineer David Clarke of DLC Design, who played a major role in the development of the ABX comparator. No audible difference was revealed in the results. This test was conducted in the 80s and apparently caused a stir at the time. In response, John Atkinson of Stereophile conducted a larger blind test set up in a similar way. This subsequent test did suggest differences.

Ozmillsy preamp shootout - Lightspeed vs ME24 pre
Conducted by:
SNA member Ozmillsy
Components tested: Lightspeed attenuator & ME24 preamp
Number of participants: 4
Level matched? Yes
Number of tests: 8 rounds of 3 samples
Results posted: view here >

Comments:

Each round had one of each, then a third sanity check where either was played. Each marked a preference, with the sanity check to see if they could pick it again. Results on the sanity check were just below 50% despite comments that each felt sure they could hear a difference.

Budget vs high end system comparison
Conducted by:
Matrix Hifi
Components tested: Two complete systems sharing the same speakers
Number of participants: 38
Level matched? Yes
Number of tests: Unknown
Results posted: view here >

Comments:

The two systems shared a pair of ATC speaker with manual switching. Participants chose which system they preferred. 14 chose system A, the same number chose B and the remaining 10 admitted they couldn't pick a difference.

Monster vs Opus cables
Conducted by:
ChrisWiggles & Mike L
Components tested: Speaker cables
Number of participants: 4
Level matched? Yes - within 0.01V
Number of tests: 8
Results posted: view here >

Comments:
Chris did the write up on the AVS forum, and noted that during the first 3 of 8 trials, he was doing the test sighted and initially felt that one was audibly superior. However, in then doing the test blind, he came to the opposite conclusion - no difference could be picked.

AC power cords
Conducted by:
Secrets of Home Theater and High Fidelity & Bay Area Audiophile Society (BAAS)
Components tested: AC power cords
Number of participants: 15 (9 in one session, 6 in the other)
Level matched? Yes
Number of tests: 10
Results posted: view here >

Comments:
Answers were correct 50% of the time. Questions were asked which enabled them to determine that there was no connection between the accuracy of their answers and their opinion of their own dedication to audio, or age. There was also no link between the confidence in their answers and their accuracy. Those who were sure they heard a difference scored no better than those who were uncertain.

Cowan Audio CD player comparison
Conducted by:
William Cowan & Dane Fehlberg
Components tested: CD players, $300 Sony vs a $1800 player
Number of participants: 2
Level matched? Yes
Number of tests: Unknown
Results posted: view here >

Comments:

William had the cheaper player and did the test when comtemplating an upgrade. Both were expecting to hear a difference, but both guessed which CD player was in use 50% of the time.

CD digital transports
Conducted by:
StereoNet members Dritz, Luckydog & others
Components tested: CEC & Marantz, Dynaudio speakers
Number of participants: 5
Level matched? Yes
Number of tests: 10
Results posted: view here >

Comments:

Transports tested were both in the same price range and the final result was 50% accuracy.

Results showing a difference

Stereophile John Atkinson Amplifier comparison
(In response to the David Clarke blind test)
Conducted by:
John Atkinson (Stereophile)
Components tested: Adcom vs VTL amplifier
Number of participants: 500
Level matched? Yes
Number of tests: Refer writeup
Results posted: view here >

Comments:
This test was conducted by John Atkinson of Stereophile in response to the David Clarke test. The results overall show a slight bias towards an audible difference, but certain individual results show that certain individuals clearly could pick a difference. It highlights the importance of looking at individual results. If not for certain individuals, the results could be subject to debate.

SNA front end comparison
Conducted by: Andrew Ward (Aslan) & Terry Jones
Components tested: Two front end systems
Number of participants: 10
Level matched? Yes
Number of tests: Refer writeup
Results posted: view here >

Comments:
This test was a front end comparison. The initial concept was to test the idea that speakers and the room make up 95% of the sound and everything else makes up the rest. So for this test the same speakers were used (Aslan Minstrals) with two front end setups. A 20k front end was compared to a low cost front end, although the CD player was actually quite old and certainly not considered budget in it's time.

Most were able to tell the front ends apart and describe the differences. It was a surprise for many of them how close the sound was.

Stereo Mojo Integrated amps
Conducted by:
Stereo MOJO
Components tested: 8 integrated amps ranging from ~ US $120 - 2200
Number of participants: 38
Level matched? Set at 75 - 76 db
Number of tests: Refer writeup
Results posted: view here >

Comments:
This test is different to many blind tests as it was set up based on the assumption that there are differences. The test sample is small and amps were tested in pairs. If 4 preferred one while 3 the other, then the one with one more vote progresses to the next round. Tested this way, there will virtually always be a winner. It is interesting to note, however, that in a test such as this, the most expensive item didn't win. The surprising result is that a small cheap amplifier with very little power was preferred.

Other comparisons on the Stereo Mojo website >

2 comments:

  1. Hi Paul, Great summary never seen anything like it before ever. Saying that I once went to Govinda's Cinema in Darlinghurst, Sydney and thought the music out of there Music system sounded great. After finding out that the they ran Naim amplification I was hooked! I believe there is a Naim sound that I can pick over other other amps. Saying that I have since moved onto Class A amps again for a perceived preference. A and B comparison is a tough call for anyone as it rarely becomes a relaxed listening. A lot of 'mind noise' comes into the picture. In the end if your setup gives you a satisfying music experience every day, then you do have the right equipment. If that was a cable that got you there so be it...no I am not a cable guy! ( anymore :)

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  2. Some great links in here, thanks for listing them Paul.

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