Ohm Walsh Micro Talls: who's actually heard 'em?

Hi Emerson (Foster_9),

Glad to hear that you've turned the corner, obviously after a great deal of effort (and expense). How is the bass now, which iirc was the most significant issue earlier on? Assuming it is now reasonably good, which component change was primarily responsible for improving it?

Best regards,
-- Al

I remember one time using an Audio Control C-101 equalizer to EQ my system's room response so it measured flat. The Audio Control unit came with a microphone and automatic EQ software to enable this to be done.

The funny thing is the results absolutely sucked, and the Audio Control manual (which is perhaps the best manual I've ever read...helpful and humorous at the same time) said they'd probably suck.

I'd be very surprised if most listeners would really prefer flat room response given the opportunity to A/B the options.

Grant, I believe that a major reason for that is that the mic + equalizer/analyzer, unless it is very sophisticated, doesn't discriminate between direct (early arriving) sound, and reflected (later arriving) sound, while our ears do.

Which would seem to say that unless the room is an anechoic chamber, a setup that produces measured flat frequency response at the listening position is wrong "a priori."

Best regards,
-- Al

By *set up* are you referring specifically to the EQ I used, or by *set up* are you including any system that measures flat at the listening position?

Any system, unless the measurement equipment is extremely sophisticated and has response characteristics in the time domain that closely correspond to those of our hearing mechanisms.

In other words, a system that produces measured flat frequency response at the listening position, based on test tones, will give equal weight to sound that arrives via the direct path from speakers to listening position, and sound that arrives via reflected paths from walls and furniture.

But our ears don't work that way -- consider the Haas Effect, for example, which describes the fact that, within certain limits, our hearing mechanisms give greater emphasis to early arriving sounds than to later arriving sounds (which are presumably reflections).

And adding to that is the fact that even in the frequency domain the directional characteristics of our ears are unlikely to match those of the measuring microphone. So the microphone will "hear" reflections from side walls, for example, differently than our ears will.

Best regards,
-- Al

Line -- Yes, I have two or three binaural recordings from the 1980's, and they are indeed awesome! Too bad that a lot more recordings aren't done that way.

I think though that the subjective results they provide will vary significantly from listener to listener. What the listener hears essentially depends on the physical and acoustical characteristics of the ears on the dummy head that was used in the recording process, which will deviate to different degrees from the hearing characteristics of different listeners.

Best regards,
-- Al

Al, what you describe seems to me to be an argument against the goal of a system that measures flat in-room since the measuring is inaccurate, unless there's some measurement device that avoids or compensates for reflected sound.

Yes, exactly, although I wouldn't say "avoids." I would say the measurements, and the analysis of the measurements, need to take into account arrival time as well as frequency domain characteristics. Some computer programs will do that, to an approximation that apparently can sometimes be useful (I haven't used any of them myself).

I just listen and go with what pleases me.

You're doing the right thing!

Best regards,
-- Al

Line -- That was a good reference you provided earlier. However what I think you are overlooking is that if the room is truly "flat," in whatever way that is best defined (taking into account both frequency response and arrival times), and the rest of the audio system is flat, and the recording process was flat, and the playback volume is realistic, then our non-flat ears will hear the sound in the same non-flat manner as they would have at the original event.

Which essentially is the goal.

Best regards,
-- Al