A suggestion to all reviewers at TAS
-- Thu, 07/02/2009 - 09:48
I think it would fair to all audiophiles and especially prospective buyers to have common ground while comparing reviews of different gear from different reviewers. My suggestion is to publish power and phase response (as a function of frequency) of each reviewer's listening room using the same equipment and methodology. Here is a set of equipment that works very well:
1. Earthworks M30 measurement microphone - $650
2. Apple MacBook (any Apple computer will do) - $1000 +
3. Metric Halo ULN2 Expanded FireWire interface - $1700
4. Metric Halo SpectraFoo Complete software - $800
5. Various cables
Comparing to $100000 equipment some reviewers proudly own it is a pocket change. The measurement procedure in this case consists of obtaining a transfer function for power and phase including coherence between control and test signals. I can of course help with the proper setup, just ask.
I don't care which measurement technique will be used as long as it's the same for each listening room.
Perhaps you can post examples of such measurements and suggest how these measurements would add to the reviews.
Thanks.
Sure, here is the example:
http://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1243915681/30#31
It shows the averaged transfer function of an amplifier measured off the real speakers (NOT a passive resistive load). Similarly you can get room response by measuring the transfer function with a microphone like Earthworks M30. Basically you can measure any component of your system that way and see how it changes the signal, averaged and/or instantaneous. The transfer function has at least two advantages: it eliminates the influence of the measurement equipment (if calibrated properly) and is not sensitive to the incoming signal. It means you can do tests with any kind of musical material. There is more about this technique in the SpectraFoo user manual: http://www.metric-halo.com/beta/SpectraFoo4_Manual.pdf
No listening room is alike and so is the response. The graphs could help to make valid comparisons between gear auditioned in different rooms. Also they could help to treat the room properly (especially the coherence between control and test signals signifying room modes).
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