degrade~ bit range

May 31, 2011 at 9:40am

degrade~ bit range

Hello,

I was quite amazed that Max already had built-in beat crusher that sounds pretty decent. The “degrade~” object.

It works fine, but I’m just curious about its rate and bit depth relation.
So far, whatever sample I’ve played through, the bit depth doesn’t do anything significant over the value of 4.00. Somehow in the help file, it says that the range should be 1 to 24. The funny thing is that it seems that the help file’s own “Tone Sweep” sound file itself, does not do anything particular when bit depth over 4.

What is all about between 4 and 24?
What’s the mystery in that range?

Thanks.

#57363
Jun 6, 2011 at 11:04pm

well a sine of 8 khz will still sound the same when the samplingrate is 44100 divided by 4.

#205552
Jun 6, 2011 at 11:57pm

Are we talking bit-reduction or sampling-rate reduction here? Sampling rate is all about Nyquist frequencies innit… Bit reduction however depends on the interpolation change from one sample to the next e.g. a square will sound no different but a sine or saw will sound remarkably different

#205553
Jun 7, 2011 at 1:08pm

I noticed that as well. It’s cool but does not do much till about 6 or so. You could try Soundhacks +Decimate~ object which has a lot more crunch.

http://www.soundhack.com/externs.php

#205555
Jun 7, 2011 at 7:40pm

It is possible to design your own bit depth reducer by multiplying with a certain (high) value, rounding to whole numbers, and dividing again by the same value. The range and curvature of the control of this value is something that can be of your own design. Therefor it can be made more intuitive.

#205557
Jun 7, 2011 at 10:01pm

@jvkr I’ve thought of this too – before I discovered [degrade~] actually – and I mused that since it involves converting data from the MSP to the Max domain and then back again, that the numbers probably wouldn’t tally up that well and you’d probably get more than you bargained for on the audio crunching front!!

As a Windows user I don’t have Soundhack which is very upsetting as it does many wonderful things for me that the Cubase plugins can’t. Trying to reinvent a few within Max but the results are less than acceptable. If anyone knows of a Soundhack equivelent for Windows I’ll be all over it :)

#205559
Jun 7, 2011 at 10:13pm

@ mr_mapes

That link I posted is to free SoundHack externals for Win/Mac/Linux. There are 7 of them +binaural, +morphfilter, +spectralcompand, +spectralgate, +decimate, +chebyshev, +matrix, +compand, +delay, +pitchdelay and +bubbler – good fun.

#205560
Jun 7, 2011 at 11:10pm

A thousand thankyous mr grizzle!

#205561
Jun 8, 2011 at 9:12am

> it involves converting data from the MSP to the Max domain

That’s not correct. Anyway, it can be achieved simpler than what I said before, without multiplication and division.

– Pasted Max Patch, click to expand. –
#205562
Jun 8, 2011 at 10:28am

I’d never heard of or used [round~] before. Nice.

#205563
Jun 9, 2011 at 3:30am

Just to be pedantic…
The sampling rate determines the range of frequencies that can be represented (0 Hz to the Nyquist frequency). Reducing the sampling rate by half, down to 24,000Hz or 22,050Hz, won’t have much audible effect in many cases because some sounds have relatively little energy in the uppermost octave of our hearing range. Reducing the sampling rate much lower will of course produce more noticeable aliasing.
The bit precision determines the signal-to-quantization-noise ratio. Reducing the bit precision to 16 will in most cases be imperceptible because it’s still “CD quality”. Reducing it to 8 will produce a noise level that is clearly audible, but it’s just white noise and thus not very interesting as “distortion”. It’s only when you get down to those ridiculously low bit depths that the artifacts have more character.
See “How Digital Audio Works” in the MSP Documentation (search for ‘Nyquist’ and ‘precision’) for more.

#205564
Jul 23, 2011 at 4:16pm

One gets used to the facebook interface, and finds themself wishing there was a ‘like’ button. Excellent explanation, Mr Dobrian.

#205565
Jul 23, 2011 at 4:27pm

@Orkester

this forum seriously needs a ‘like’ or even ‘prioritize’ button; succinct, concise and vital explanations such as this deserve to be pushed to the front of the forum queue; to prevent n00bs (guilty) of asking questions that have already been answered. Dreaming…

Brendan

#205566

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