USING NOISE- pink, white, brown

[roomjello]

I thought this might be an interesting discussion.

What are ways you know of to use noise, all types?

 

Pink noise:

I have found it valuable for testing old equipment. I buy old stuff on ebay and can check the EQ points or overall output curve and level(or levels of all outboard gear relatively for that matter) to see if they are where they should be by running pink noise to it/them.

Simply mult the noise, one goes direct to the daw and one through the unit then back to the daw.

Voxengo's gliss eq has a function where you can run a number of inputs to the visual graphic display and compare them. So the untouched noise is one line, the piece of gear is the other. I can check my 4 track tape machine the same way in and out of repro and all kinds of other gear.

This is great way to see if gear is running full bandwidth and a great way to calibrate converters etc too.

 

If you have a plug like Voxengo'sCurve eq or harbal you can take a sample of pink noise and use it to test the flatness of a mix.

 

 

White noise:

-Great for triggering with a kik or snare etc for some added grit

(play with the crest factor for harsh or smoothness).

 

-As Craig pointed out, it is good to run while listening to a mix as it masks and lets you know if some levels are out of whack.

 

-Great for calming a baby(again, paly with the crest factor)

 

-Apparently good for helping distract from tinnitus

 

 

Brown noise:

I have no ideas or uses on this one, looking forward to reading some.

 

 

 

Btw....Here is the unit i use for my software noise and signal generator, it's cheap and very easy to use;

http://www.esseraudio.com/en/test-tone-generator-windows-software-generate-test-signal-sine-pink-noise-crest-factor.html

[WRGKMC]

I used to use it all the time as a tech for testing gear. You'd pass pink noise through a circuit and signal trace the signal till you found the problems.

You'd use test tone generator too for plotting the frequency responce, matching caps and transistors etc. Sometimes you'd get distortion in a circuit

at a specific frequency and gain and all those tools were employed to isolate and correct the problems.

I still use it for setting up a live PA occasionally along with a DB meter to balance the horns mids and woofers when using s three way crossover.

For recording, I have less use for it besides setting up the playback amps or for tuning a room.

 

You can download a trial copy of RAL (Realtime analizer) which is a professional grade testing system. It generates the test tones and measures them accurately.

Its only designed for a stereo system though. (I bought a paid version and its is a great program but its best used on a laptop or system with a stereo interface only.

It lockeds out all but two channels of a multichannel DAW. Getting it off the computer was a bitch too because you got to dig into the register,

then if you want to use it again you need to request a new code)

 

You do need good quality reference mics to use it but It will allow you to test room acoustics and such.

Knowing how to use it is of course a profession unto itself, but it may help to isolate some issues that can be corrected with bass traps.

I used it after building my studio and was able to correct some major problems I was having.

 

I suppose if you're into speaker cabinet building it would be good to use or anwheres where you need to test or calibrate a full frequency range.

Some home EQ's for HiFi have a built in mic and test mode that pumps pink noise through the speakers. Then you adjust the EQ bands to match the actual room responce.

I suppose its better than nothing in getting a HiFi playback system set up.

[roomjello]

There is a cool bit in 'mixing with your mind' about putting noise through the gtr amp and using headphones to monitor while you place the mic in the sweet spot. It works really well.

[WRGKMC]

I dont know. I get enough noise from my drummer to last me a lifetime.

My battel is minimizing it to make music transparent.

If theres no silence between the beats theres no contrast between the two.

I do understand it though. A crecendo of a loud rock band is a maximum dynamic thrust

much like pink noise in both sound and energy. I just dont connect pink noise with energy.

Guess its more of a disturbance any more, like waking up in front of the TV in the old days

when the channels went off the air and the pink noise would wake you up. They used that to good effect

in the poltergeist movie.

 

A simular thing is used in painting. Some use a white background

to lighten the other colors of the paint. Another method is to use a black background to

darken the colors applied. Since white consists of all colors in the spectrum and black is an absence of color

(or white reflects all colors and black absorbs them all)

You learn to use both contrast extremes of light in painting ans you should learn to use both

noise and silence in recording where its useful artistically to do so.

[gubu]

A question or 2:-

 

 

White noise: -Great for triggering with a kik or snare etc for some added grit (play with the crest factor for harsh or smoothness).

 

 

How do you play with the crest factor of white noise?

 

The crest factor relates to the ratio between average and peak levels, is that correct? So you would be compresing/limiting in order to 'play with the crest factor'?

 

I'm just trying to learn. Call me a student and educate me please!!

[gubu]

 

The attached Multi-Sine with a high crest factor can be used to test meters. The meter must read 0 dBFS. Most Peak or RMS level meters will fail reading the right level.

 

 

So the meter should be reading 0dBFS peak?

 

And I can calculate the crest factor of this Multi Sine by taking the RMS value on my meter and dividing into my peak value?

 

That seems clear so far.

 

The big question is, how does one 'play with the crest factor', as suggested by Roomjello above. With compression/limiting, or by other means?

[gubu]

 

Almost all digital sound processing will change the crest factor, i.e. EQ-ing, Compressing, De-esser and so on. Only decimating with the fader doesn't change the ratio between Peak and RMS. Ratio = the difference between Peak and RMS

 

 

That all makes sense. So you'd need a lower crest factor for 'smoother' white noise in Roomjello's example, and a higher one for 'harsher' white noise.

[MikeRivers]

How do you play with the crest factor of white noise?

 

Why in the world would you want to do that?

 

The crest factor relates to the ratio between average and peak levels, is that correct? So you would be compresing/limiting in order to 'play with the crest factor'?

 

Why compress? You can measure the RMS and peak of white noise, so you can determine the crest factor. Because it's random, short term measurements won't be alike, but if you live long enough you'll get a good average measurement of something useless.

 

Curiosity is a good thing, though. More interesting to measure the crest factor of the recording of a song.

[gubu]

Why compress? You can measure the RMS and peak of white noise, so you can determine the crest factor. Because it's random, short term measurements won't be alike, but if you live long enough you'll get a good average measurement of something useless. Curiosity is a good thing, though. More interesting to measure the crest factor of the recording of a song.

 

Well, yes, that's kind of my question.

[gubu]

 

Not really, no. Nobody thinks in crest factors when we produces music. I don't even think there are any PAR meters in any DAWs.

 

 

Mastering engineers might refer to it or be aware of it? But if you're aiming for peaking at -.1FS and RMS at -10ish, then there's your crest factor right there I suppose.

 

I hope Roomjello gets back soon and explains himself!

[MikeRivers]

 

Nobody thinks in crest factors when we produces music. I don't even think there are any PAR meters in any DAWs.

 

Perhaps nobody thinks of the numbers, but mixing engineers, and particularly mastering engineers are aware of it. Music with its natural (uncompressed) dynamic range typically has a crest factor of around 20 dB. Reducing it to around 10 dB gives the typical "hot" sound of modern recorded music.

 

There aren't crest factor meters because you have to measure the RMS level over a long period, 15 seconds to a couple of minutes. But there are a number of DAW programs and plug-ins that will measure RMS and peak levels over a selected time or the entire file. Sound Forge is one. You can calculate the ratio yourself.

[roomjello]

You guys are deep muthafaka's.

If you get the software i linked to it has a crest factor slider for both oink and white noise, 1-10, yes 10 is harsher or more diffuse sounding.

 

Albert is trying hard to appear smart, but is failing miserably.

[rasputin1963]

I once had a set of ear-training tapes for the aspiring audio guy. It included a number of "aural illusions" to marvel at.

 

The illusion that really blew me away, was:

 

A brown noise tone was played in the right channel (of your headphones). The recording then removed a notch of about 20Hz in the signal, then swept that (silent) notch slowly up-and-down the brown noise frequencies.

 

The result? It sounded astonishingly like the brown noise tone was migrating spatially from the ceiling to the floor and back up again. And this was happening ALL IN THE RIGHT CHANNEL ONLY. In other words, audio experts have reason to believe that the human ear hears azimuth (up and down the Y-axis of imagined Euclidian space) sourcing PER EACH EAR ONLY. Thus, our two ears and their "stereophonic" response is NOT THE ONLY 3D AURAL CUES WE HUMANS RECEIVE.

 

Pretty kewl, huh? It's believed that your pinnae (your external ear skin + cartilaginous structure) create that "notch" naturally in the audio each ear perceives.

 

I think they used a brown noise signal because it was rich in frequencies, but had nothing figurative about it to distract from the 3D effect.

 

I keep waiting for the day a record engineer says he used azimuth tweaking deliberately to achieve apparent 3D sourcing along the Y-axis.

[techristian]

Remember the PAiA Chord Egg KIT. It played different types of white, brown and pink noise for relaxation. Other than that, I only used noise to synthesize cymbal sounds and snare drum sounds. Feed noise into a VCA controlled by an ADSR.

 

Dan

[roomjello]

 

I once had a set of ear-training tapes for the aspiring audio guy. It included a number of "aural illusions" to marvel at. The illusion that really blew me away, was: A brown noise tone was played in the right channel (of your headphones). The recording then removed a notch of about 20Hz in the signal, then swept that (silent) notch slowly up-and-down the brown noise frequencies. The result? It sounded astonishingly like the brown noise tone was migrating spatially from the ceiling to the floor and back up again. And this was happening ALL IN THE RIGHT CHANNEL ONLY. In other words, audio experts have reason to believe that the human ear hears azimuth (up and down the Y-axis of imagined Euclidian space) sourcing PER EACH EAR ONLY. Thus, our two ears and their "stereophonic" response is NOT THE ONLY 3D AURAL CUES WE HUMANS RECEIVE. Pretty kewl, huh? It's believed that your pinnae (your external ear skin + cartilaginous structure) create that "notch" naturally in the audio each ear perceives. I think they used a brown noise signal because it was rich in frequencies, but had nothing figurative about it to distract from the 3D effect. I keep waiting for the day a record engineer says he used azimuth tweaking deliberately to achieve apparent 3D sourcing along the Y-axis.

 

 

I have done some reading on this, there is something in "the new stereo soundbook" where they use a 1 octave band of noise centered at 8k and then take notches out.

If you notch 8khz, that gives the illusion of sound coming from above the head at a 45 degree angle or so.

Not sure if 2 ears are required, although they are listening in stereo headphones. Moving the notch to 7.2 k makes the sound come from in front on the horizontal plane and moving it to 6.3k makes it sound like it comes from below.

Very interesting stuff.

What was the tape set you had called Rasputin?

[rasputin1963]

 

What was the tape set you had called Rasputin?

 

 

 

I can't remember the title of the series. It was about 4 cassettes. I bought it in 1990 at the old bricks-n-mortar store in Emeryville, CA, when the publishers of ELECTRONIC MUSICIAN and KEYBOARD had a fantastic assortment of audio books available.

[Huh?]

Hey, where'd all those A.Einstein quotes come from?

[elsongs]

 

I thought this might be an interesting discussion. What are ways you know of to use noise, all types? White noise: -Great for triggering with a kik or snare etc for some added grit (play with the crest factor for harsh or smoothness). -As Craig pointed out, it is good to run while listening to a mix as it masks and lets you know if some levels are out of whack. -Great for calming a baby(again, paly with the crest factor) -Apparently good for helping distract from tinnitus

 

 

I like to sleep with an electric fan or an air purifier on in the room, for the sole reason that they generate white noise, and help me fall sleep.

[rasputin1963]

 

I like to sleep with an electric fan or an air purifier on in the room, for the sole reason that they generate white noise, and help me fall sleep.

 

 

Ditto. Especially useful if there is some car noise outside. Of course psychotherapists have those little noisemakers outside their consulting rooms, so patients in the waiting room can't hear the geshrei that's going down in the shrink's office.

[Raymar]

I actually used some white noise in a tune called Viewing the Cosmos as sort of a cosmic dust sound that drifts in and out at times.

[roomjello]

 

I like to sleep with an electric fan or an air purifier on in the room, for the sole reason that they generate white noise, and help me fall sleep.

 

 

Same for my lady. Me, i like pure silence so so much for sleeping. Ear plugs make for nice sleepy time.

[elsongs]

Same for my lady. Me, i like pure silence so so much for sleeping. Ear plugs make for nice sleepy time.

 

Yeah it's hard for me to sleep with total silence. I can hear myself think.

[roomjello]

Yeah it's hard for me to sleep with total silence. I can hear myself think.

Right.

[philbo]

I have to wonder if you mean Brownian Noise (i.e., discovered by Robert Brown) or the Brown Note (the legendary magic bass note that causes involuntary bowel movement to commence).

 

discuss...

 

By the way, here are a few other colors of noise:

http://en.wikipedia.org/wiki/Colors_of_noise

[A. Einstein]

Brown noise is exactly in the MIDDLE of pink and white

 

 

 

 

Sleep well.