# [music-dsp] high & low pass correlated dither noise question

```I read a pretty cool article the other day:
https://www.digido.com/ufaqs/dither-noise-probability-density-explained/```
```
It says that if you have two dice (A and B) that you can roll both dice and
then...
1) Re-roll die A and sum A and B
2) Re-roll die B and sum A and B
3) Re-roll die A and sum A and B
4) repeat to get a low pass filtered triangular noise distribution.

It says that you can modify it for high pass filtered triangle noise by
rolling both dice and then...
1) Re-roll die A and take A - B
2) Re-roll die B and take B - A
3) Re-roll die A and take A - B
4) repeat to get a high pass filtered triangular noise distribution.

What i'm wondering is, what is the right thing to do if you want to do this
with more than 2 dice? (going higher order)

For low pass filtered noise with 3+ more dice (which would be more gaussian
distributed than triangle), would you only re-roll one die each time, or
would you reroll all BUT one die each time.

I have the same question about the high pass filtered noise with 3+ more
dice, but in that case I think i know what to do about the subtraction
order...  I think the right thing to do if you have N dice is to sum them
all up, but after each "roll" you flip the sign of every die.

What do you guys think?
```
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