Pink (or white) noise to EQ an amp. Anybody tried it?

George Kimery · From: Limestone, TN, USA

When I was into PA, I had a pink/white noise generator and a hand held spectrum analyzer. It was great for setting the PA EQ at different venues. Has anybody ever tried this for setting your amp EQ? or...have an opinion?

Jamie Mitchell · From: Nashville, TN

why? it doesn't make sense...

j

Tim Marcus · From: San Francisco, CA

it makes sense for a large PA system because you are trying to get the response in a room to be as flat as possible.

For an amp, it makes less sense because they are not "flat" to begin with - mostly due to the speaker and its frequency response.
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Donny Hinson · From: Glen Burnie, Md. U.S.A.

Setting anything "flat" just sounds counter-productive. I may be off base, but wouldn't it make more sense to set it where it sounds good?

Murray McDowall · From: Warrnambool, Victoria, Australia

Sure have George, that's how they set my hearing aids up! Rolling Eyes

Murray.

Scott Duckworth · From: Etowah, TN Western Foothills of the Smokies

I always just use my ears. I remember singing in a church with another group a long time ago. He set up his stuff after mine. I have already done my "EQ check" with my ears. He used one of those fancy mics and EQ setter thingy.

The pastor and many others told me that my sound was much better....
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George Kimery · From: Limestone, TN, USA

I was in no way suggesting that and electronic gizmo be used instead of your ears. What bought this on was my BX 500 amp, which has EQ controls out the ying yang plus a graphic equalizer. It just struck me out of the blue that there was enough controls to use pink noise and a spectrum analyzer to give you a starting point for EQ from one venue to another.

I wish I still had my system, I would give it a try and see what the results would be like. So far, I have got some good opinions, but looks like nobody has actually tried it.

I am an experimenter by nature and like to explore all possibilities. I was asking the question more out of curiosity than anything else. Your ears certainly trumps some electronic gadget to set the sound that you like. The spectrum analyzer would tell you where the peaks and valleys are and guide you more to a flat response, but that could be a bad thing. Where the peaks and valleys are could be the biggest part of the sound that you like.

Les Cargill · From: Oklahoma City, Ok, USA

If you had some way - and some place - to compare the output of the amp against a known-good standard, this might make sense. Even then, you might be able to do it enough to have a sort of mental model of what it should be.

But your hearing will be quite different day by day in my experience.

There are a few notes on my guitar that tend to be a bit more prominent than they should be, so I use those to EQ by. This is similar but I'd think easier than shotgun blast of full broadband noise. And it'll be less annoying Smile

Most rooms we play in aren't treated very well, we're probably too loud* and there are lots of other obstacles to good sound. But do what you can. The main thing is to reduce low-mid buildup.

*this seems to be impossible to actually fix. band I'm in now has a running conversation on the subject. I make sure they know I'm wearing earplugs, but ...

And remember - the EQ knobs go to the left ( down ) as well as to the right.

Dave Mudgett · From: Central Pennsylvania and Gallatin, Tennessee

I've used white (actually pink 1/f noise) noise generators with a spectrum analyzer with a PA to figure out a room's hot frequencies and come up with a reasonable initial EQ for the room. But to me, that's where the process starts, not ends. After that, you still need to figure out what sounds good. But this can give you, from room to room, something like a level playing field to start with. And it also gives you some knowledge of where the hot frequencies are, which I think can be very useful in setting the overall EQ.

I don't think this is generally needed in a small club, but I think it can be useful in a tricky room with weird acoustics and/or where the band is playing too loud for the room. I think all this is really unnecessary if the band isn't pushing the volume to the limits of the room. But even if useful, there are pitfalls:

1. This isn't something you generally want to be doing with the audience in-place - neither the management nor audience are gonna appreciate being subjected to that type of noise;

2. So people generally do this in an empty room, and then the acoustics change with a ton of people in there.

But I think there are some situations where it's useful. I guess the same concept could be applied to a guitar or steel amp, but I think it's less important. First, in most shows I do (and I think this is more the norm these days), everything is miked and guitar amps are not the primary contributor to the overall room sound. So beyond getting a good stage sound, the issue is EQing the PA. Second, even when that's not the case, I don't generally find that a guitar or steel is pushing the hot frequencies the way the overall mix does. In my experience, if the mix is loud, most of the time it's dominated by kick drum and bass, which are almost always reinforced via the PA. If the mix isn't loud and not pushing the limit of the room, EQ is easy if you have reasonable ears.

DG Whitley · Posted 7 Sep 2015 8:42 am

I pretty much agree with Dave, using pink noise and spectrum analyzers get you to what I call a "zero base" reference to start to "color" the sound as you like it. But again, as previously stated, this is usually done in an "empty" room. The acoustics change when people start filling the room. So having a good set of ears will help you make the changes necessary to the EQ to keep everything together.

Again my experience was for the PA, not sure what, other than getting you that "zero base", doing that to an amp would accomplish.

That being said, what do I know?

My 2 cents, YMMV.

Lane Gray · From: Topeka, KS

I'm with Tim.
You want the sound system to do this to tune the PA to the room.
For the amp, you want to send the PA a signal that sounds good.
BUT, if you know what curve on the RTA sounds good to you, you could send the pink/white noise through the amp, and adjust the knobs til you get the curve you want.
I'm not convinced it's a good use of the resources at hand.
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George Kimery · From: Limestone, TN, USA

The places I play are family friendly and are set shows with a starting and ending time. We get to the places an hour and a half before starting time, so they are empty rooms. I could run the pink noise without bothering anybody, but as pointed out, it would be in an empty room.

I don't think the whole idea is very practical and not worth the effort. Once again, I was just curious if anybody had tried it and what were the results. It just never occurred to me to try it when I had my system.

Bo Borland · From: South Jersey -

We always used to analyse the room to find which frequencies would generate feedback. Using a 32 band EQ we could eliminate the spikes and round out the curve.

It's not for doing an EQ on your guitar

Bill A. Moore · From: Silver City, New Mexico, USA

We used to call it "ringing in the room". Turn the gain up until feedback, then back off the frequencies that cause it. I would then back off the gain to a working volume level, and adjust to taste, (same with the monitors). We never had an analyzer.
I really don't know how to translate that to a guitar amp.

Glenn Demichele · From: (20mi N of) Chicago Illinois, USA

Hi George, I've got a bx500 too. I've messed with noise, but the spectrum plot on my scope isn't fine enough, so I just looked at amplitude and used a sweep generator. I've used it when I was trying to figure out what was going on with speaker cabs I've built, but the most useful thing I used it for was cloning the freq response of the amp section of my twin. I couldn't tell the difference when I was done. The twin clone isn't what I ended up using, but it was neat. When playing bass, I eq to the room to get rid of modes by ear. I hardly ever change settings on steel for the room, but if I have a problem, just moving the speaker around usually fixes it.
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Larry Henson · From: Texas, USA

I would like to reply.....but after playing for 40 years I have no idea what you guys are talkin' about...what in the world is "pink noise"............Larry

Brad Sarno · From: St. Louis, MO USA

http://whatis.techtarget.com/definition/pink-noise

James Holland · From: Alabama, USA

I used to attempt a similar technique for hi-fi setups and placement. Since the amp is part of the instrument and not intended to produce a flat response, I'd think you would only be looking for unnatural peaks and valleys due to room and placement issues. Maybe using pink, white, or gray noise (FM radio static is close btw) as ear training for a few times might enable you to find and cut/boost the trouble frequencies, provided you are using a 15 or 31 band eq?

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