Room EQ: When new is Expensive, Old will do


Recently, I moved and had to set up my stereo in a new room. It is a good room, generally, but after a while I started to notice a certain heaviness in the upper bass with all the speakers I tried, regardless of my efforts to reposition them for more even response. This bass heaviness made certain recordings sound thick, overblown, and unnatural.

I measured the response with a meter and Stereophile 3 test disc and found I had a broad peak around 125Hz. My wife would not allow a lot of acoustic room treatments (tube traps, etc.) in the room, so I did some research to find an equalization system that might work to tame that bass rise.

What I found was that all the major audiophile systems, i.e., the PARC, TACT, DEQX, etc, all cost over three thousand dollars. It seemed like a lot of money just to tame one bass peak. I also looked at a pro unit (7-band parametric equalizer) from Rane, that was available for about $800 on the web (you need two units for stereo).

Meanwhile, just for the heck of it, I had an old Dynaco 10-band graphic equalizer in my closet that had worked well in a second system in the past. I figured what the heck I could try it for free and if I couldn't get good results I'd just buy something like the Rane, or perhaps a used TacT (though the digital nature of the Tact was a concern).

In short, I installed the Dyna EQ and cranked down the bass at 120Hz. I also added a mild boost at 60Hz and 30Hz. When I remeasured the system I was able to dial in the sliders with the help of the test disc and meter. Of course I didn't get it dead flat, but I got the large peak under control and bolstered the low bass a small amount.

In listening to the system now, the heaviness/bloat is gone and I can hear more bass and midrange detail. The presentation is definitely more natural. I am actually very surprized that I cannot hear ANY sonic degradation from passing the signal through the Dyna EQ.

In a way, I was fortunate in that the peak was at a frequency that could be controlled by the set frequency positions of the Dyna unit. But the whole experience has me wondering why audiophile equalization components need to cost over $3000??? Perhaps the TacT or the PARC, or the DEQX could fine tune the response a little better, but I'm very pleased with my results and at this point I'd rather keep my $3k in my bank account. I doubt that even critical audiophiles listening to my system would feel that the room acoustics are a problem at its present level of performance.

I just wanted to share this story and see if perhaps some others may have had a similar experience.
plato
ive done pretty much the same as you only i used older model mcintosh mq101 eqs to do the job,i measured the response thru a dbx 20/20 eq analyzer & corrected the problems with the old mac's.

if you want more modern gear without spending a ton dbx makes several different analyzer eqs that usually sell for 500$ or less. 20/20 10/20 14/10.

i use my dbx 20/20 on a pair of mcintosh xrt22 speakers & the mcintosh mq101 on a pair of klipschorns.

mike.
Bigjoe, I appreciate the tips on the dbx units. I'll have to look into those.
Digital room correction can be a real can of worms, especially with the various units available. If you are on a budget and want to see what one can do with something like this, you can always try the Behringer units. While i know that they make a full-range room correction device, i also think that they offer a unit that is designed for low frequencies with a built in crossover. This is probably designed for use with a sub would be my guess. Don't know if you could incorporate the bass EQ without engaging the crossover though, so who knows.

Other than that, the newer digital devices do SO much more than just EQ. The amount of work that these units can do would have taken a computer the size a few years back. Technology is really moving along, but unfortunately, not all of it is implimented in ways that are "sonically superior" for audiophiles. Sean
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I have a Behringer DSP/RTA which I use for room measurements. You can measure the room and then invert the room profile and correct for it with the DSP. It plays back through your system to produce a "flat" response. What I have found is that while technically correct, the sound is very unnatural and stilted. The natural room resonances which can be a warming factor, are sufficated. So, I would not recommend going in this direction. It is better to deal with room issues directly, in my opinion.