chrisbates
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Feb 28, 2005

Auto EQ at the Gig

Used to have a Driverack which I used to Auto EQ
rooms and venues where I had repeat gigs. It worked great and I could store it as a preset, so next time I was there, I just "dialed in" the room EQ, and it was perfect every time.

I like the remote on the PAS, but I do a "one man band" thing with a Voice Live, and computer, and between calling up the backing tracks on the computer and setting the harmonies on the Voice Live, I'm often too busy to tweak the remote EQ.

Behringer has a new unit with Auto EQ..the Ultracurve 2496, which is way less expensive than the Driverack.

Anybody have any experience with either, as an insert to the PAS? Any thoughts on the subject?
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davecfraser
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Feb 10, 2007

Re: Auto EQ at the Gig

VEry interseted in people's comments on the Ultracurve ANd the L1 model 2
Dan_Cornett
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Jun 6, 2005

Re: Auto EQ at the Gig

I used to use an (older) Ultracurve with a conventional set of speakers (pre-L1 days) ... both with an "installed" system and with a "transportable" system. I've also used a combination of an Ultracurve (AutoEQ) along with a "feedback destroyer" (automatically creating notch filters).

I have not had an occasion since use the L1's where I wanted to break out the Ultracurve -- especially since having the T1 available to create a notch filter when necessary.

Now a little (a lot?) on the theory and my 'philosophy':

The idea behind an auto-EQ is to "normalize", or compensate, for the idiosyncrasies of BOTH the room and the audio system in order to create an overall "flat" (equal) response across the frequency range. This is typically done by using a high-quality "reference" mic, feeding in pink noise (which has equal power at all frequencies) and measuring how the speakers, amps, and the room emphasize or reduce various frequencies ... and then creating a "mirror image" of that response to (in theory) give an overall audio result which is "flat".

This can work o.k., but is fraught with simplifying assumptions which can result in less-than-stellar results. Here are some of them:

1. When you try to create a 'flat' EQ, you may be striving to eliminate the "good" acoustics of a particular room as well as the "bad". Even the greatest concerts hall are not "flat" in their "room EQ" ... that is part of what gives them their "character", just as each person's voice has it's own distinctive character.

2. The "acoustic response" of a room changes as a result of a number of factors:
a) the overall volume at which the "reference" was taken.
b) the amount of people in the room (this "reference" is rarely done with an audience, because it can be most irritating!) -- although some more sophisticated systems have attempted to do the same with subtle 'chirps' rather than simple 'pink noise' while an audience is present.
c) temperature and humidity changes.
d) placement of speakers and mics. With "installed" audio systems, the speaker placement doesn't change, but otherwise this can be terribly significant.

3. The audio components may not be adequate to truly compensate for the "bad" characteristics of the room, which can lead to distortion or other generally weird effects.

Now, with L1 Systems as your "audio source", one of the major "variables" -- that of the speaker system -- has been already "tuned" to give a consistent, uniform sound. All that (should be) left is the response of the room itself -- and I've not felt I needed to compensate for that in most cases.

I will say that for an INSTALLED system I would include a multi-band EQ and do some amount of "room EQ" (even using MA12's, which are sonically similar to L1's), although usually not for the purpose of making the room EQ "flat", but simply to minimize some of the narrow "problem frequencies" inherent in the room. For example, in many rooms the "empty of people" EQ may sound a bit "too bright", but once it is filled with an audience the sound can be "just right".

===============
All that to say:

I've tried an Ultracurve with an L1, but didn't think it added enough value to mess with.

This information is now also in the L1 Wiki at Auto EQ and the L1.
davecfraser
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Feb 10, 2007

Re: Auto EQ at the Gig

THANKS! Awesome post man!