Is there such a thing as audiophile parametric eq?


My listening room is of awful dimensions (close to 1 x 2 x 4) and I've used treatments and bass traps to get the imaging and bass response to be very good. Yet there are some frequencies especially in the mid-bass that are very loud compared to everything else. I was considering buying a Behringer DEQ2496 after hearing rave reviews of what it can do in a home listening environment. Then I found out that the SPDIF I/O is optical and that threw a wrench into that plan. What I need is either a very good digital eq that uses RCA SPDIF or a very good analog PEQ. Any suggestions?
jlambrick
Restick,

I am with Rives. You should not average listening points to get an "average" signal as this totally defeats the purpose of correcting for room modes by smearing/smoothing out the problems.

However, in contrast, you should not seek to iron out every bump/null at every 1 Hz data point and get a ruler flat response at one spot....who is to say that one spot is the most representative of the signal quality within your sweetpot area (and after all your ears are 6 inches apart and do some averaging themselves). Who is to say that your zealous corrections are not making it worse 2 feet to the side or causing phase irregularities from sharp filters, for example?

Go for the big broad bumps at lowish frequencies and forget chasing 2 Hz nulls. Once you are satisifed take some measurements around the sweetspot and see how wide an area you can achieve. The biggest sweetspot comes from having a largish room and from treating all the corners and as much of the room as you can with absorption (includes furniture) that works down to say 50 Hz (big thick absorbers). Another factor is leakage....a room that leaks (wood frame) is better than a basement with five surfaces that are concrete. (although a leaky room may disturb others in your home it is usually better sounding)

Perhaps Rives can add whether it is best to stick with 1/6 octave or to do each frequency Hertz by Hertz up to 200 Hertz or so?

Remember also that many speakers produce 10% or more harmonic distortion at realistic levels when driven at low frequencies below 80 Hz (especially small ported designs) In this case your response plot may become misleading, as what you think is a mid bass problem may be caused by excessive harmonics from low frequencies causing mid bass bloom.

A bass guitar with fundamental notes between 50 and 100 Hz will produce 2nd harmonic between 100 and 200 Hz the second harmonic and higher will be part of the signature sound of the bass guitar anyway. However, your ears are roughly 10 decibels more sensitive to 150 Hz than 75Hz and therefore a second harmonic that is only 30% as loud as the fundamental will sound equally as loud as the fundamental note. If you add typical speaker or harmonic amplifier distortion to this then you can easily see how mid bass can get over boosted and the guitar much stronger than the musican/recording engineer intended...all without even considering any room mode problems.

Good luck...
Rives, your last explanation does make sense. Of course, I don't have nearly the
experience you do with respect to measuring different rooms and corrections ;).

Shadorne, thanks for your response - good points as well. So far I have not
really gone the equalization route (except for smoothing out the subwoofer
response). Mostly very careful room placement and a little treatment.
Shadome: We measure with a continuous sweep, so it's not averaged at a specific octave. However, we do have a psycho-acoustical response filter that integrates much like the human ear. Lower octaves are integrated with larger intervals than higher octaves. I also agree that corrections should be for significant issues--not 1 Hz issues, but the psycho-acoustical response filter takes care of that automatically for us.
Why does it seem like using an EQ is like blasphemy to most audiophiles. I have heard a good friends mega buck system sound amazing with a TACT (modded). I also heard a reasonably impressive demo of the lyngdorf at RMAF.
Bflowers...Back in the 1950s when I became interested in audio, equalizers and tone control circuits were lousy, and audiophiles were right to avoid them. But the circuits that have been used for the last couple of decades do not have significant problems. However, it takes a long time to live down a bad reputation, and avoiding equalizers is an article of the audiophile religion. (You used the right word..."blasphemy").