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I moved this discussion to another thread. The test we did was double blind but did not use any device. Rather all the capacitors in the crossover were removed and replaced between trials. All the capacitors were measured so the values between the different types under test were the same. The test worked as follows. I downloaded a random sample test sequence from the web and printed it out so I knew which set, either a or b to use for each test. Listening was done first with both sets of caps where the listeners knew what the caps were. After they had a chance to listen to both where they knew what they were, we started the blind test.

This section of the test was done by asking all the listeners to go into another room. I then put in the capacitors from group a or b depending on the random selection sheet I had. I then left the room before the test started so I could not affect the test. When they were through with the listening and recorded their choices they left the room and I returned to put in whatever set of caps was called for on the random sheet. I then left the room again, the listeners returned and the next sequence of test began. This continued for the whole series of tests.

At the end, no one was able to determine beyond 50% certainty which capacitors were used for each test. That is as accurate as a flip of the coin and nowhere significant. This was not my first rodeo and the same results happened each time I was part of similar tests, either as a listener or running the test.

What this or any double blind test means is that for this group of subjects with this equipment and this music no one was able to determine a difference. Other situations may yield a different result. It is important to note that before the test the concensus was that there were huge differences in the caps that anyone could hear on any music but that proved not to be so. I'm sure this will in no way change the opinions of the die hards who insist on the overwhelming superiority of this or that component, but in all my years of audio, I have found that the biggest differences by huge amounts are in three areas, the recording and mastering over which you have no control other than to get other source material, your listening room, and the speakers, primarily the drivers, enclosures or lack thereof, and the proper design of crossovers, not necessarily the choice of "super" components, but rather components of good quality properly configured. And ofd course, a good passive crossover can be as good as a good active crossover, but is a pain in the behind and very expensive to produce. It also locks you in to a certain result unless you want to forever swap out components. Also, you cannot do those changes on the fly as you can with actives.

So this is another case of ya pays your money and ya takes your choice. It is a hobby and you need to do whatever floats your boat.

Tom

tomp,
Very interesting results from the test.

I will take a high quality DSP crossover over any passive component between a solid state amp and speaker any day.

Tom,

You are talking about crossovers inside Merlins?

No, it was an outboard crossover on diy speakers set up to quickly change capacitors.

Ok. Fair Enough.

What was the objective of the test?
Is the listener asked to identify A or B
or
The listener asked to share his sonic experiences of what is currently played?

There is a huge difference between the two.

The objective is to see if the listener can tell the difference. By definition if they can detect no difference, they sound the same and therefore there can be no preference for the sound of one or the other. That is the basis of blind testing. If they sound the same, how can you have a sound preference. You may like other factors such as looks, fit and finish, peice, etc. but the sound is the same.

Tom

Hey Tom,

Can you list the capacitors tested, what kind of crossover (2-way, 3way, 6db, 12db, etc.), and where in the crossover topology the tested caps were located?

Thanks,

Chris

I don't remember the details of the crossovers and caps but all the equipment including speakers came from Stuart. If he is reading this thread perhaps he can fill in the details. I do remember that none of the caps were bipolar electrolytics.

Tom

I don't know the crossover details either. I do remember assembling several brands of film capacitors @ 4.7uf. None actually measured 4.7uf however. There were easily heard differnces between the capacitors with slightly different values. Only 2 brands measured close enough to double blind test. I think they were approximately 4.4uf and within 1% of each other. No one was able to correctly identify the difference. I imagine few actually measure the competing capacitor brands they are comparing in this type of application to less than 1% and most of the differences heard are the varying values.

To be fair, the system was set up pretty hastily and not set up for optimum performance before starting. Hell, that could take weeks/months and require significant room treatment. I believe it may be possible there could be a difference between capacitors in spacial or atmospheric characteristics had the system (including the room) been capable of showing those characteristics. We really were only able to compare basic, but critical characteristics like toneality, and timbre.

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Walt