White noise is named after white light. In physics white is not a colour so much as all the colours mixed together. This is demonstrated simply by shining white light through a prism, where the light will be split into a rainbow spectrum off all the visible wavelengths. Same applies for sound, white noise is simply all the frequencies mixed together.
White noise as a build up
In dance music, white noise is used a lot. Usually as the track builds up to a drop, there is a rising effect that builds up the tension, this is often white noise with a band-pass or similar filter automated to increase in frequency.
Let me show you how to get this effect.
First of all open your DAW. I shall, as always, be using Reaper. Either add a sample of white noise, or open up a VST instrument with a noise generator. In this case I shall be using a sample I downloaded. If you are adding a sample, hit CTRL+T to add a new track and then hit insert. This will open up your files and you will be able to add the sound you downloaded.
open a new track and hit insert key
Select your sample and click open
Your sample will now have been added to the track. I normalised it because it was very quiet. (right click and go to Item Processing)
Once you have your white noise sample you want to make it to the length needed e.g 16 bars of build up or another time of your choosing. The sample I used was 4 seconds long so I copy and pasted a few together, then selected them all and glued them (right click and select Glue Items). We now have a workable piece of white noise that we can use to our hearts desire. Here is what we have so far...
So, now we want to manipulate the sound to make a rising effect. This can be done very simply by using automation and ReaEQ, Reaper's stock EQ plugin. First you want to open up the effects and select ReaEQ, if you don't know what to do, click here.
You will now have the ReaEQ window.
The picture above demonstrates the next step. It is very simple to do. Delete all but one point by clicking on each and clicking remove band. Then for the remaining point select it and under Type, set it to band pass. This means only that band will be audible. I then reduced the bandwidth so it was narrower and more specific.
If you then play the white noise and move the band across the spectrum, you will hear a rising and falling pitch effect. see below.
Now once you have done your playing, we can automate it how we like. This saves you controlling it yourself, and means you can let the computer do it for you.
To open the automation section look at the track bar and select the button on the bottom left corner
(underlined by the blue)
This takes you to one of Reaper's best features where you can automate pretty much any setting you like. Scroll though if you have to to find the ReaEQ section. With automation you need to know what setting you want to change. In this case it is the band pass frequency so you will check that box.
If you have lots of effects or there is a VST instrument, expect a much bigger box with potentially hundreds of things to automate. This is simple as we only have the one simple effect.
You are left with the track and a line below that can be used to change the value of the setting. It works on a vertical axis so the line will be at minimum at the bottom and maximum at the top. For this automation this means we want the line to rise as time progresses.
We need to add a point with which we can make a change so right click on the line and select Create New Point. This will make a second circle on the line which you can drag about and change. Since we want a rising effect, we shall make this new point at the end of the sample and move it to the top to make a upwards slope.
This is nice. Let's hear how it sounds...
We can go further with this and edit the shape of the slope, I like to make it start with a low gradient and increase the gradient towards the end like an exponential curve. This is simple to do. Just right click on the first point and click Select Point Shape then select Fast End
There are more options to try but this one is being used as it has a cool effect.
This will leave the line looking like this...
...And sounding like this...
So what can be done with this? If we just dump it over a build in a track, it will sound amateur. So we can add a few cool effects to it. One idea would be to sidechain compress it, using the kick to trigger the threshold (if you don't know what this is or how to do it then click here), this will create a bouncing effect that will "slot" it better into the music. Another idea would be to use a rhythmic trance gate on it so it rhythmically plays on and off, this coupled with a beat sync'ed delay and reverb sounds really nice. This effect doesn't even have to be done with white noise, any harmonically rich sound will work although make sure it is in key if it is a chord or note.