There are a few colorful noises in audio. Pink noise. White noise. What does it all mean? When I have a question, I consult wikipedia.org. Their description of pink noise is:

1/ƒ noise is used… to refer to any noise with a power spectral density of the form

where ƒ is frequency and 0 < α < 2, with α usually close to 1. These “1/ƒ-like” noises occur widely in nature and are a source of considerable interest in many fields.

There. Does that clear it all up?

In other words, it’s generally accepted that pink noise is the sound of all frequencies at the same volume. It sounds like static, or snow like when you try to tune your analog TV to a station that doesn’t exist. Do you wonder how this is helpful?

Considering all of the gear you send your audio through puts their own little stamp on the sound, and that your room has its own characteristics of shaping your sound, generating pink noise through the system allows you to hear how different frequencies react to each other, the gear, and the environment.

Unless you’re good at hearing quality static, you’ll want to SEE the difference in frequencies. In this case we use a special measuring microphone that connects to a Real Time Analyzer. The microphone has a flat response, meaning it does not alter the audio frequencies at all. The analyzer will display what the mic hears, and the volume of each frequency, usually in 1/3 octaves, or 31 bands from 20Hz to 20kHz.

The theory is that if you make your 31-band EQ look like the OPPOSITE of this read out, your sound system will sound flat. But, what if the measuring mic was in your sound booth, and now you move it to the middle of the room? Oh… you were smart enough to do that in the first place? Well, move it to the side of the room, where most of the audience is. Or how about back by the wall, or under the balcony, or IN the balcony, or in your choir loft if you have one, or… get my point? The audio does not sound the same everywhere, and won’t, no matter how hard you try.

No one (with few exceptions) uses pink noise on the road. The pros know what good sound sounds like, and will play the same test music night after night after night in every room they’re in. You may not have the opportunity to hear 6 different sound systems and rooms in a week like I did, but you can still teach yourself to trust your own ears.

I don’t think pink noise is a bad thing. I like using it as the starting point though, instead of the ending point. Put your measuring mic in the middle of the room and run your pink noise. Tweak your house EQ until the graph is flat. Move the mic around. Make a few adjustments. Now, put on that song that you KNOW how it should sound. Wait until no one else is in the room so you can blast Back In Black, or some Zeppelin, and play with the EQ until it thumps a little more, or the guitars sound a bit crisper, or the vocals start to jump out.

Forget what the meter and the graphs are telling you. Use that flat EQ you got from the pink noise as your starting point. From that point on, use your ears. No one says this has to be a 1 hour exercise, or even 1 day. Start over again the next time you get a chance. Take pictures of your graphic EQ and compare them. Do you notice a trend? Are certain frequencies ones you grab every time? That might be a good one for your room.

One word of caution here. Don’t worry about frequencies below 63Hz. Unless your Sunday service is a rave, you won’t need those, and you’ll only over-work your amps and stress out your speakers. Similarly, a lot of extra high-end can do more damage than good. Remember our motto, that less is more. Don’t feel like you need to mess with every slider. Try to limit yourself to 5-6 changes. Also, try to avoid major differences from 1 slider to the next.