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In Reply to: Re: DEQ 2496 and DAC 1 posted by aljordan on December 8, 2006 at 12:41:25:
Alan, read your article. It's very interesting and informative and should be read by anyone contemplating the purchase of a DEQ 2496. I had one question for you--you describe cutting response at various freqencies. How did you determine where to cut? By ear and then by estimating what the needed frequency point was? I see that you have one of their callibration mics. Did you use that--you imply it's not necessary, or maybe that the auto curve it comes up with can be better done by hand. Anyway, thanks for the info and the article!
Follow Ups:
I am planning to try it with the DEQ 2496 when I get my soundcard hardware sorted outREW ~~Room EQ Wizard~~
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Julien
"There's someone in my head, but it's not me"
Thanks...will print it out later!
This looks pretty good. I'll download it tomorrow and try it out. Thanks for the link.
Hi Tom,I used the Behringer ECM-8000 measurement microphone set up at the listening position to take some measurements. The DEQ2496 has an input that will accept that (or any other measurement mic), and you don't need to use a microphone preamp with the DEQ. The DEQ has a setting which allows you to output pink noise, and you can look at the microphone response on the DEQ's display when in RTA mode. I definitely would recommend the microphone unless you are good at translating notes to their numerical frequencies by ear.
To use the auto eq mode on the DEQ, you would need to have a measurement mic hooked up. I used the ECM-8000 because it has a reasonable flat response, is not expensive, and the DEQ has built in settings for it. That being said, if you run an auto-eq with a flat target curve, the results will most likely sound awful. It is not so much the fault of the DEQ as it is the basic fact that a flat in room response generally sounds awful. I played with the auto eq settings, but in the end found better results manually setting the parametric equalizer because the parametric offers way more control than the standard graphical equalizer.
Note that the unit can be set up completely by ear, but I definitely found that using a measurement microphone allowed me to more quickly identify where the problems exist in my room.
You can get excellent results by doing something like the following:
Using the DEQ and a measurement mic, you would set up the mic at the listening position, use the DEQ's pink noise generator and look at the results displayed on the RTA screen. Then use the parametric eq to first dial out the humps you see below 200 hz. The parametric eq allows you to find nearly the exact center point for a given adjustment, allows you to set the width of frequency range that the adjustment will affect, and allows you to cut or boost that range up to fifteen db in half db increments. You can have the adjustments affect both channels, or a single channel. If you are going to work on each channel separately, make sure that the pink noise is only playing through the channel you are adjusting.
I said to first only apply cuts to the frequencies where there are room humps because that has the most profound affect. Reducing the bass frequencies that are drowning out other frequencies will give you much deeper apparant bass response. You can then apply a boost to the frequencies that are showing nulls in the room, but you have to be careful here because applying boosts will make you amps work harder, and will require you to lower the overall output volume of the DEQ in order to avoid digital clipping. I mentioned that it is most effective to apply the eq below 200 hz because the wavelengths are fairly large, and eq at those frequencies will be affective over a fairly large distance near the listening position. Once you start trying to apply eq at the higher frequencies, the wavelength nulls and peaks are so small that the eq is affective for only the single position of where the measurement mic is. If you move your head less than a foot you can get radically different results.
It is, however, very affective to apply general eq in the higher frequencies if you have a general problem you want to fix. In my case, I like a bit more of a BBC dip than the designer of speaker dialed in to the crossover, so I applied a 2 db cut centered at 2500 hz that had a width from about 1500 hz to 3500 hz. A small adjustment like this had a big effect in overall listening pleasure.
Don't expect to buy the DEQ and have it working flawlessly in an hour. It is a fairly complicated piece of equipment that really requires a couple of close reads through the manual. If you are located in the U.S. I can guide you through some of the tricks over the phone.
You da man!!! I've been playing with the DEQ for a few months now to marginal results. I just did your recommended adjustmenst and HOLY COW ... what a difference. Thank you for the posting
Cool. I'm glad you have it working well.
Alan, thanks for the great detailed answer. It fills in the missing pieces--I couldn't figure out from your article how you did it and this post certainly explained that well. I printed off a copy (of both) for future reference. Now, the quest to find $350 for the eq and the mic!
Tom
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