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Discussion in 'AV Receivers' started by EricB, Sep 28, 2003.
Same question folks, and if you do, what type/brand do you use? Thanks.
I tried using a good quality analog parametric eq to deal with low freq room interaction effects. No matter how hard I tried, I could not get the response with eq'ed sub plus eq'ed mains to be as good as just eq'ed sub alone. So I gave up and sold it. I even used http://www.etfacoustic.com/ but no dice. One big issue, is I use a digital eq for the sub, so very easy to dial in freq and attenuation for each peak, but the analog eq has dials and knobs and just wasn't that easy to use...
I guess I can answer yes, since I have a AudioControl Bijou 6 Channel EQ which is ALWAYS in the signal path, no ,matter how many channels I am using. Having said that, methinks that EQ in the bass region is the critical piece unless you have a magic room with perfectly placed speakers and a sub. The Bijou has 1/6th Octave sliders for the sub from 20hz to 80 hz, and 1/3 octave for the LCR from 80 to 800. This is a THX device that I assume was designed to work best with a THX speaker suite, that have limited vertical dispersion. My guess is that the lack of anything above 800 hz has to do with the fact that the THX credo expects that you are going to be in the direct (as opposed to the reverberant) field, and that the room will play a minimal role above 800 hz. In practice, it works wonderfully to help voice match the L/R to the center, which, even if from the same vendor will sound very different since it is normally a horizontal MTM array, versus a vertically arrayed L/R. And 1/6 in the below 80 Hz area works wonders to tame peaks, and address small, non-null induced valleys. BGL
Like Brian I use the bijou and the audiocontrol R130 RTA. I dont adjust the room nulls just the peaks, I use pink noise from 20hz to 20,000hz to see the freq response I also use CARA room set up computer program to help me get the best placement for my speakers it takes along time to get it right once you do its worth it. Brad
Thanks for the replies so far guys. It seems that common to the three of you is that you EQ just the low frequencies. So for the rest of the frequency band, you would like to keep it pure? Is speaker placement then (with relation to room acoustics)only critical to the lower frequencies? So how do we compensate for dips in the higher mid-range and above frequencies, supposing we don't use equalizers? By the way, I am still talking about Stereo Music material. And thanks for the link, Kevin, quite an interesting site, and software as well. Thanks again. PS: I'm having an extremely difficult time posting, can anyone help me? Even if I'm already logged, I have to re-enter my username and password for countless times to get my message through.
not here, I wont even allow tone controls in my signal path
Eric, I bought my main speakers for their stereo sound quality, but when adding a subwoofer needed to EQ out some low-bass room-induced modal peaks. My mains are rated [email protected], so I crossed them over to the sub one octave above that (@60Hz). I put an electronic crossover with symmetrical (low-pass and high-pass) 4th order Linkwitz-Riley filters (24dB/octave slope) in the signal chain just before the stereo amp inputs. I then used the SUM bass switch on this crossover (L+R for the low-pass) and sent the low-pass to a Behringer BFD (24 band parametric EQ) and then to the powered sub. The BFD cut the bass peaks in the room to smooth out the response at the listening position. See my equipment list below.
Thanks for the reply, Bruce. I was going to ask you about the connectors for the BFD; but then, I tried to search it on the web and got the answer. Thanks again. So, for the upper frequencies, do we usually leave them without any EQing?
Yes. Harmon Kardon EQ8
Be careful about using a BFD for the main channels. There are definitely sound quality issues with using that device with high freq material. No problem for a sub (and anything less than 200 Hz or so), but 10 kHz to 20 kHz, not a good idea.
I agree with Kevin, which is why I explained my setup and pointed out the BFD was on the Sub-out cable only, not the full-range signal cables.