Anyone actually EQ a room?

Following on from a recent post on EQ.

Does anyone EQ the room in a live setting? I have got a QSC Touchmix which gives the ability to do this and yet I never use it. Am I right in thinking that you can play some reference music through the system and then adjust the EQ to get the sound how you like it ?

[James May]

Yes, the pro sound guys do it all the time. They are actually EQing the combination of monitors and room together.

This is one of those situations that in theory should be easier than it actually turns out to be in practice. The big variable in small rooms is: what listening position should you EQ the system for, and how much are you willing to mess up the perceived response in other listening positions?

I've done it to great success in controlled studio spaces with plenty of attention to acoustic treatment first. In typical small clubs and listening rooms, to my mind, all bets are off. I hope some folks with this kind of experience will share their experience.

[Methos1979]

Our system is very simple and basic, just a guitar and two mics, into a Boss VE-8 Acoustic Singer pedal and that into a Bose S1 Pro. All the three-band EQ'ing on the guitar and wife's mic are done in advance on the Boss VE-8. Changes made at the venues are individual volumes for guitar and her vocals on the Boss as needed, minor tweaks to notch and effects levels also on the Boss and then final EQ tweaks (bass and treble only - there are no mids) on the Bose. But I don't change the guitar or vocal three-band EQ at the Boss level venue-to-venue. I have yet to need to do that. Usually it's just setting the volume and then sometimes dialing back the lows on the Bose at the venue. Sometimes notch will change a bit as well, though not much.

[ljguitar]

Hi Mojo

Back in the day when even larger venues didn't have as good equipment as our band, we'd threshold-feedback-tune rooms (send everyone out of the room for about 45 minutes).

And often on permanently installed systems (like churches) we'd go in and threshold-feedback-tune the room and the stage for groups which were experiencing issues because they moved speakers, or acquired new equipment.

Our band PA had ⅓ octave EQ, compression, BBE Exciters etc in a rack and we knew how to deploy them.

Venues have gotten better systems, and sound techs are smarter/better taught to run the gear. We sure don't feel the need any longer for that kind of fine tuning. Instead of focusing on gear (2 hour setups) we are more into just putting out the best music we can.

In the past 10 years I haven't felt the need to do serious alteration of the room gear, since most rooms are pretty average and our equipment is flexible enough so it works. My current small PA has 10 band EQ which is almost always set flat, and feed back suppression (on demand and we've not used it in 10 years).

How about the rest of you guys? We carried big rigs for 25 years, that was enough!!

[Akousticplyr]

Originally Posted by Mojo21

Following on from a recent post on EQ.

Does anyone EQ the room in a live setting? I have got a QSC Touchmix which gives the ability to do this and yet I never use it. Am I right in thinking that you can play some reference music through the system and then adjust the EQ to get the sound how you like it ?

Yes I do this with my Touchmix at new venues when I can. The room tuning wizard needs a microphone like this:

https://www.sweetwater.com/store/det...ser-microphone

I also run the feedback wizard, but keep in mind that both of these functions tend to put out "unpleasant sounds" so I wouldn't run them while customers are sitting in a bar for example. The manual calls this "ringing out a room" or "ringing out a system".

And of course, both are only a starting point. Add a lot of bodies during a gig and you'll need to compensate by tweaking EQ.

[Chipotle]

There's "ringing out" the system, to eliminate any feedback prone frequencies. For the small PA we use at my school, we have an ART-231 graphic EQ. While it doesn't have the automatic wizard, it does have a detection circuit that lights up the slider for a frequency that's feeding back. See the light, duck that frequency. It makes ringing out a piece of cake.

There's also "flattening" a room by using a pink noise generator, reference mic and spectrum analyzer with the EQ. The idea is not just to find feedback frequencies, but compensate for all the frequency "humps" in a space so that what you hear at the end is the source sound, unshaped by the room. I think this is what James is referring to.

I agree that it works best in a controlled, treated space, but way back in the day (mid-80s), we did just that when I DJ'ed at small clubs. I had a DAK (remember them?) graphic EQ/spectrum analyzer with a pink noise generator and a supplied mic. We'd pump the pink noise, then set the EQ so the signal coming from the mic looked flat on the analyzer. And guess what? It most definitely made things sound better! We'd stand out on the dance floor and A/B the EQ'ed and bypassed music. It certainly made our cheap sound system sound... well, less cheap.

Now, a DJ setup is a far cry from a live sound reinforcement setup with mics, monitors, amps, etc. But I'd say you'd get at least some benefit from that kind of processing no matter where you are.

[agedhorse]

Yes, eq'ing the system response to correct (where possible) for the response of the room. Pretty much every day of my professional career.

Originally Posted by agedhorse

Yes, eq'ing the system response to correct (where possible) for the response of the room. Pretty much every day of my professional career.

Thanks for all these replies, I’m going to try this on my next rehearsal to see if I can see any discernible difference.

[agedhorse]

Originally Posted by Mojo21

Thanks for all these replies, I’m going to try this on my next rehearsal to see if I can see any discernible difference.

Here's something that might help you get more out of equalizing. This discusses 2 parametric mid bands on an acoustic amp, but the same thing applies to the channel eq on your TouchMix. Of course you won't be working with physical controls, but the same thing applies to the virtual controls. :

4. The fourth way is by the use of equalization to reduce the amount of energy in a specific frequency band, thus reducing the tendency to feed back in that band. Since this feedback is often aggravated by cavity resonance of the instrument’s body, it’s often most easily accomplished by using the LOW MID eq controls. Starting with the LOW MID GAIN control at the 3:00 position and the LOW MID FREQUENCY control fully clockwise position, set the gain control while playing to a little bit below the level that feedback occurs, now slowly rotate the LOW MID FREQUENCY control counter-clockwise and at some point you should hear the resonant characteristics of the beginning of feedback. Reduce the LOW MID GAIN control to about the 10:00 position and the sound of the resonance should pretty much disappear. You will probably find that rotating the LOW MID FREQUENCY control back and forth a bit from this point, you will find a spot that works the best. If you need a little more cut of this frequency band, you can rotate the LOW MID GAIN control counter-clockwise a little bit more. Note that the BASS control naturally overlaps the lower end of the LOW MID range, so if you find that you are cutting below ~150Hz on the low mids, you might try turning the BASS control down a little too.