Ok, so we were gluttons for punishment. DIY2004 was upon us and we decided to do the cap tests in DC and Dayton. Neil from the Madisound board made a second cap testing rig and gave it to Dennis Murphy. Bob Cardell brought his rig. So we had two separate setups in different rooms with different equipment and different speakers. I am not getting into what equipment since all the results were the same :)
Bob upgraded his setup to allow blind testing where the user switched between A and B for a while. Then Bob would (behind us) randomly change the AB so we did not know which we were listening to. This was really hard I was sure I could hear it for a while but then lost it. Bob's system was comparing a mylar cap to an expensive boutique cap we all know and love.
Dennis's rig had three caps with a three way switch. His system used an expensive cap, a Solen, and an electrolytic. This was really hard as well. Dennis did not do the random part but did take sheets with people's guesses.
The bottom line on the whole day was that nobody did better than flipping a coin.
We posted this on the DIY sites and were inundated with "suggestions" on how we were full of you-know-what.
So being sadists, Bob and I take the cap test to Dayton with suggestions from Ph.D. level people on how to make the tests more reliable. We could take do all the suggestions due to time limitations but we tried.
In Dayton, we rented a hotel room and ripped the room apart a'la CES and set limited seating for the suckers . . .umm. . . .contestants. The randomizer was still used with Bob behind us. The direction was to AB until you felt comfortable. Then repeat your selected piece as you tried to answer two questions: "can you hear a difference", and "which one sounds better?"
I did the test late in the evening and spent some serious time and energy trying to pass. Power listening is really hard. Bob was not cutting me any slack. I really thought I had it nailed, but I scored with everyone else; same as flipping a coin. I also listened to Dennis's version in DC but really focussed on the AB section and never went to the C side since I could not hear anything in AB. Turns out side C was the electrolytic so maybe if I have done AC instead of AB, I would have heard something. This is where most everyone is, thinking that in some variation we would have heard something and our egos would be intact.
Now the caveat is that we may truly have missed something which simply invalidated all three tests. Or maybe our statistics 101 was too many years behind us. But the results were the results. The feelings of the participants basically fell into three groups:
1) I have heard cap differences a million times. There must be a flaw in the system.
2) That was fun and I am not good enough to hear the difference, was having an off day or was tired.
3) I know I can hear cap differences. Those @#$%@#$^$% idiots have no idea what they are doing. I am so embarrassed I participated such an amateur event.
I do not want to close the door on there being potential flaws in the overall system. The bottom line is that it is harder to tell than some might suggest.
So there it is. Last year we did cables and did hear a difference only if we compared zip cord to fine cable. This year caps and we heard no difference. Next year I think we should try resistors.
Copyright Peter J Smith 2004, Retrun to helarc.com