Techniques and tips

[Vic]

I am going to need to eq all the cabs I build and would like some advice...as per. I have read the EQ piece by Rane and can have a lock down eq for the mains in my DRPA and provide a room eq if needed in the shape of my dbx 1231. That said what is the preferred method of establishing a flat response in the first place. I have read plenty on the DRPA users forum and PSW amongst others. I have at my disposal the dbx rta mic, a Phonic PAA2 and some software, Allen & Heath RTA and may well buy the True RTA or download the trial SMAART. I know it has to be measured in free air. Is it best to use pink noise, measured on axis. At what distance and what level in SPL. The PAA2 can be used to measure output levels including voltage etc. The PAA2 has a handy feature in that it can store up to 10 measurements and then an average taken to given an average eq setting. Any more advice would be cool, and I will then post my findings.
Ta
Vic

[Bill Fitzmaurice]

Measure outdoors, away from buildings, at least ten feet from the cab, with a fairly loud signal, to drown out any potential environmental noise. With PAA2 use its own pink noise generator, average at least four readings, it can tell you how to set a 31 band EQ based on its results. It works very well and is simple to use.

[Vic]

Ok
What weighting?
I am cool around the PAA2
I used it on Saturday to do an average room reading
I used A weighting
It wanted me to boost the low end lots, which my ears told me me would be wrong. I guessed that it was because I wasn't running the pink noise loud enough, I was using the pink on the PAA2 CD. I also have the Binks CD.
Thanks again

[Zack Brock]

I'm also curious on the weighting. I had assumed "Flat" would be best when EQ'ng speakers for flat response, but my PAA3 also has "A" and "C" weighting. I realize what A & C are for, but do you EQ your speakers with that weighting?

[Sydney]

"measuring sound-pressure level"
The Master Handbook of Acoustics By Frederick Alton Everest
p39

This link
http://www.carstereo.com/help/Articles.cfm?id=60
has a section
5. Adjusting processors to smooth out frequency response
That details compensation figures for C weighing

[Bill Fitzmaurice]

I'm also curious on the weighting. I had assumed "Flat" would be best when EQ'ng speakers for flat response, but my PAA3 also has "A" and "C" weighting. I realize what A & C are for, but do you EQ your speakers with that weighting?

Always flat.

[Vic]

Thanks for the recent replies. If I have time before a gig I do try and get some room readings but I don't often have time. I don't use the RTA mic with the DriveRack at all. I will use the PAA2 as a quick reference sometimes when ringing monitors, I work on my own and eq from the desk. Generally I have little time to do too much setting up so on my main eq I tend to pull the regular offenders, 250/315/800/1.6/3.15 a little. Listen for 'boxiness' in the vocals - normally bewteen 200 - 280, some bass boom, normally 100 (my sub cross-over point) and play a little music for any obvious peaks. During the bands I may adjust a little more if anything else becomes obvious. My rig doesn't deserve a $squillion alignment system seeing as it consists of 4 front loaded ground stack cabs. Thanks for all your help though.

[gdougherty]

I'd recommend setting it up outdoors as Bill recommended and get a good EQ that way. Use this as your "do not touch EQ" and make room adjustments on another EQ if possible.
I've had excellent results with very little added EQ using this method when indoors.

[Zack Brock]

Measure outdoors, away from buildings, at least ten feet from the cab, with a fairly loud signal, to drown out any potential environmental noise. With PAA2 use its own pink noise generator, average at least four readings, it can tell you how to set a 31 band EQ based on its results. It works very well and is simple to use.

I'd recommend setting it up outdoors as Bill recommended and get a good EQ that way. Use this as your "do not touch EQ" and make room adjustments on another EQ if possible.
I've had excellent results with very little added EQ using this method when indoors.

What is the appropriate height to measure at outdoors? Does the height affect the measurement? I tried this Monday night on a set of speakers and I just picked 10 feet high. Only problem, I had to stand on a ladder to take the measurements with my PAA3. If that is the correct height, that is fine, but would be nice not to have to do it on a ladder.

One thing I've noticed, it seems the PAA3 always wants to decrease the bass content (everything under 160Hz or so). When I follow the suggested EQ, it always seems too anemic for my tastes. I realize AutoEQ and/or average EQ (like on a PAA2/3 unit) is not the end-all-be-all of speaker setup and that as the link Sydney posted suggests, you are suppossed to EQ to taste after you've set it flat.

Have you guys found that you have to increase the bass frequencies a few dB on your EQ to compensate for taste? Or do you leave it pretty much flat as the autoeq/average EQ suggests?

[Bill Fitzmaurice]

What is the appropriate height to measure at outdoors?

Measure them as they'll be set at a typical gig. The RTA process is only intended to give a base EQ setting as a starting point. Season to taste.