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Old 24th September 2013
  #53
Quote:
Originally Posted by mpr3 View Post
Wow you guys have been busy. I don't even know where to begin.

Rumi, I mentioned the CADs because you said you have three of them and they are known to be very consistent, much more so than vintage Gefells (or vintage anything for that matter). I do realize that getting those large caps close enough is going to be a challenge, but give it a shot! And then, if you have three of the same Gefell caps, give that a go, but realize that the cap deltas could be large enough to throw off their 'constant' in this experiment.

As far as testing is concerned, there is no need to over think this. Many of us have been A/Bing or A/B/Cing mics and pres for decades and know how to avoid skewed results:

1) Multiple takes after swapping the mics across the preamps, even if they are identical and capsule aligned.

2) Label the mics 1,2,3,4,etc and label the pres A,B,C,D,E,etc with little stickies, and then name your files accordingly: A1 or B1 or B3 or C4 etc. Avoid naming the files with pre names. This will help you keep a gap between the manufacturer and your expectations.

3) Keep listening tests blind by either bringing in a second person to help switch during listening, or devising a way to randomly play without you looking at the playback file: B3

4) In addition to the different takes involved in the methods already outlined in this thread, also do different 'rounds of takes' where the gains are 5db up or down across all pres. You can label this into the files as: A1-5 or A1+5, along with your nominal A1.

5) And for the freaks among us, try to use similar mic and power cables.

Thats it! Again, acoustic guitar is awesome for this, especially since you can exploit the boominess in relation to the high end transients. It doesnt have to be a record friendly recording, just one that delivers solid information for the listeners to discern differences.

Have fun!
You forgot one of the most important parts: Level matching. And, there is a lot you don't mention that may completely flaw the results as well, but we're off topic and I'm not going to get into it. Carry on....