Parametric / graphic equalizer recommendations

The advice thus far is good, but there are a few areas I would like to caution you on. First, I should tell you that we manufacture a parametric EQ and as such I am biased towards it. However, we designed it with very specific goals in mind and I think it's important to understand those, even if it may not be the eq for you, you can learn from our design strategy. All our company does is small room acoustics. Thus our design not only reflects a superior technical design, it also reflects our philosophy on room acoustics.

The unit is called the PARC for Parametric Adaptive Room Compensation. It is a stereo 3 bands per channel unit that offers variable Q (width of the curve), attenuation, and center frequency. The unit is specifically designed to attenuate bass room modes. Thus it only operates from 18 to 350 Hz (we recommend that it only be used from 200 Hz and below) and it attenuates ONLY. We have it attenuate only because boosting low frequencies can cause other problems such as overdriving an amplifier in a particularly low impedance point of a particular speaker. We also limited the frequency to bass response only. This is because anything above this can be easily treated in the room and we strongly believe in NOT using an equalizer unless you have to. Bass modes are difficult to deal with passively and the PARC is a very practical solution.

The other aspect of the design was sonic quality. We listened to digital correction systems and felt they all thinned the sound. Additionally, we did not want another A/D or D/A conversion that might not be as good as the source from either high resolution digital (SACD DVD-A) or vinyl playback systems. We were looking for the ultimate in transparency and went with an analog design.

Thus I would caution on using an EQ in the higher frequency. You can get rid of brightness in a room and it may be a combination of absorption material, bass re-enforcement, and the speakers. Do you by any chance have a lot of windows in the room? They leak bass badly and will throw off the balance of the system and cause it to sound bright, not unlike a room that does not have enough high frequency absorption.

You can visit our website for more on this unit and go to our listening room where we have tutorial on some basic room acoustic problems.
http://www.rivesaudio.com

Cdc, No answers yet to your specific question, but good responses nonetheless. I don't think you'll find anyone here who has actually used one of these equalizers, so, since they're so inexpensive, why not blaze a trail and let everyone know about your experience?

In response to two of your questions, you need two channels and 1/3 octave (31 band). You need 2 channels because if you are trying to undo room reflection problems (ignoring Rives's very good advice), they won't be the same on each side. You need 31 band because unwanted peaks are sometimes very narrow and you dont want to create a suckout in a nearby frequency.

I agree with Rives, however, that you should only use an equalizer to correct low frequency room problems. I have had brightness problems in one of my rooms, and tried almost everything you can think of, finally deciding that the speakers I had in that room were not suitable for that room. Now, with different speakers, no problem.

I am tempted to ask what speakers you are using. As soon as you answer, however, you'll get 20 recommendations of other speakers, and I know you are pretty familiar with the sonic attributes of a variety of speakers. Others would ask what cables you are using, etc. Let's not go there. It may be that your speakers are just bright. I noticed you commented once that a certain small inexpensive speaker was dull sounding, where I find the same speaker a little rolled off but not dull. Most audiophiles' systems and speakers are too bright for me, the inevitable result of the neverending quest for "detail."

Some things to consider: any glass or other hard reflective surfaces in the room? coffee table between you and the speakers? drapes over windows? how low is the ceiling, and what distance between the speakers, ceiling and you? Speakers tilted back at all? have you tried them in a different room? What happens when you set them up in a nearfield configuration so the sound you hear does not include any reflections?

Good luck,

Paul

I need more info to really answer your question. First, what is your system? Second, what do you mean by bright? Are you talking about an emphasis in the 5-8khz range, or do you mean excessive high frequency (>10khz) content? As a rule it's always better to address the root cause of tonal imbalances. My experience is that parametrics are something of a band-aid and of limited effectiveness. Graphic EQs are even less effective.

Well, I'm so impressed by the thoughtful responses I'll say more than I want.
1) Spent a week with our local symphony orchestra and going back to my system, made me realize how bright, even tizzy on a bad CD it can be. At one point I listened to the orchestra with a Yamaha MS-100 monitor up to my left ear and orchestra in my right ear. I could instantly go from the monitor to real music and compare the two. The active monitor was bright even with treble turned way down. It was like shining a spotlight on the high freq.
2) I had a high quality mini system for 18 years. When the recorder stopped working on one speaker, and since I could afford it, stepped up to Nautilus 804 / Musical Fidelity. My room is 13' x 15'. No carpeting, hard walls, and windows on one side with a thin drape. Got the system in Oct. 2001. You can't imagine the amount of stress this whole stereo stuff has been as this was a huge sum of money for me and not even sure why I did all this. I do not part with my money easily. I'd sell it all right now except for the thousands of dollars I would loose. This is because now this whole mess has given me recruitment with associated permanent hearing damage. There are times when in only 10 minutes at 65 dB (conversational level) my ear is burning and in pain. Mild pain which goes on for days. People talk in my room louder but after 10 minutes the stereo is killing my ears. Understand that I never listen above 80 dB and usually around 70 dB so I have not been some smart ass who did this to himself.
I did cover all the walls and floors with carpet and blankets and this cut the reverb but it took something on every wall to help. But this is not enough in my case.
I refuse to turn my living room into an anechoic chamber and I'm not looking at different speakers because of some preference issue. The high frequencies need to be attenuated in a precise and adjustable way. If someone wants to suggest interconnects, I'd want to see measured high frequency attenuation, not just what they hear.
I agree that the reverb has to be addressed, maybe with a carpet. But need to stress: This Is NOT Enough. So if I cannot roll off the highs my whole stereo will go and in a way I'll be glad. I used the CD input on my boom box today, turned down the treble, and listened to music for the first time in almost a month. But even with this, now my ear is paying the price.
Any suggestion would be welcome.
I wonder:
- Why won't a parametric eq. work on high freq's?
- What is exactly bad about graphic eq?

How precious. Right down to the use of "loose." I see I apparently missed where you said room treatment didn't work, but no one responding above intended any offense. Sometimes we're distracted, or sleepy.

Back to your questions. Either, or any, kind of equalizer should help immensely, though I have to add, there is a difference between brightness and harshness. Maybe you should just get a nice receiver or an integrated amp with a treble control that you can turn down.