Hi there,

I am trying to reasonably emulate a bitcrushing/downsampling/waveshaping guitar pedal. After having put together those three functions, I realised (looking at videos on the net - I don't actually owe the pedal) that when bit depth/samplerate are set to maximum (best sound 'quality') and a 'unitary' wavetable is used (doesn't modify anything in the sound), the actual pedal still provides a broad "distortion/fuzz" sound. (of course the video provides clean and effected sound, ensuring comprehension)

As the sound I actually get with my patch is deceiving yet logical, I came to the conclusion that the clipping stage has to be 'upgraded'. I replaced the previous [clip~ -1 1] with a [tanh~], and I found it interesting but still far from satisfactory.

Googling about analog fuzz/distortion/overdrive gave some hints, but I'm still far from being able to put together a 'simplified physical model' of such a fuzz/distortion.
So I will try to start with a good transistor electronics book, to see what is the difference between germanium and silicium devices, and see if I could use some caracteristic curves to build a [diode~] and a [transitor_amplifier~] objects.

Any help appreciated !

Thanks,

Nau

bt is a good artist but I don't follow him he is the one who made the shutter edit vst(load of crap) and always dose alot of exponential thing with metter and fx with c sound ok so he already come out with its called trash. http://www.izotope.com/products/audio/trash/

I edited your post because I don't think this is the appropriate place to be bashing people's religious views. Please try to be more considerate. -Maelstorm

Trash has been around for several years. I doubt BT had much to do with it. Anyway, the only part of that link that says anything about "non-standard" distortion is the multi-band distortion part. That could be done with just band-pass filtering different frequencies into different types of distortion.

may be its some thing else that he was saying I know he did some thing micro with every sample point thinking its may know of like the gormeter vst where you cam delete wave points and picks to give you some thing new

Gosh ! Very rude.

I edited the sendspace link since I realized my lastly posted archive was not actually a folder but a bunch of files (sorry for the mess). fixed.

Is there anyone here that owns or knows well the TubeScreamer pedal to give me some comments about the quality of the model ?

I noticed the tone parameter is rather subtle, certainly not as the one implemented in the DS-1 model.

Thanx,

Nau

@Maelstorm said:

I would recommend using [lp10_cheb~] for this as it has a very steep roll-off. You could probably set it to about 18kHz without aliasing.

Ok. And as I'd like to take account for other sampling rates than 44.1kHz, is it "correct" to calculate the cutoff freq. of this cheby with a simple "fc=(SR/2)-4kHz" ?
This would give approx. 20kHz for a 48kHz SR example.

Thanx,

Nau

Hi,

as I was 'porting' my disto patch to Max/msp, I had to figure out what permutation and sign rules could change Puredata biquad filter coefficients into Max/msp [biquad~] coefficients. I found these rules comparing coeffcients given by the excellent [filtercoeff.mmb] made by Maelstorm to those calculated by a 'classic' [filtergraph~] in Max/Msp.

Here are two patches allowing to make this conversion in one direction or the other.

Nau

http://www.pdpatchrepo.info/hurleur/msp2pd_filtercoeffs.pd

Hi,

as I was 'porting' my disto patch to Max/msp, I had to figure out what permutation and sign rules could change Puredata biquad filter coefficients into Max/msp [biquad~] coefficients. I found these rules comparing coeffcients given by the excellent [filtercoeff.mmb] made by Maelstorm to those calculated by a 'classic' [filtergraph~] in Max/Msp.

Here are two patches allowing to make this conversion in one direction or the other.

Nau

http://www.pdpatchrepo.info/hurleur/msp2pd_filtercoeffs.pd

@nau said:

Ok. And as I'd like to take account for other sampling rates than 44.1kHz, is it "correct" to calculate the cutoff freq. of this cheby with a simple "fc=(SR/2)-4kHz" ?

It's better to use (SR/2)*0.8, or something like that. They roll off at dB per octave, not per kHz.

I realised (looking at videos on the net - I don't actually owe the pedal) that when bit depth/samplerate are set to maximum (best sound 'quality') and a 'unitary' wavetable is used (doesn't modify anything in the sound), the actual pedal still provides a broad "distortion/fuzz" sound. (of course the video provides clean and effected sound, ensuring comprehension)

@acreil said:

@nau said:

Ok. And as I'd like to take account for other sampling rates than 44.1kHz, is it "correct" to calculate the cutoff freq. of this cheby with a simple "fc=(SR/2)-4kHz" ?

It's better to use (SR/2)*0.8, or something like that. They roll off at dB per octave, not per kHz.

Logical, indeed. Thanks

Just re-uploading the project, DistOdrive.pd is the main patch.

http://www.sendspace.com/file/phvsjt

Hi there Nau! I know this is an old thread, last post was 2 years ago! But do you still by any chance have your patch?

Hi SockPuppet,

here is the archive I think is "the one". I won't have much time to check it before next week, but if you encounter problems I'll do it.

https://www.sendspace.com/file/1tn9zk

Nau

@nau Awesome! Thank you so much!

On first glance I can see that the audio files are not working within the patch. I'm also getting the "divided by zero" error. I'll dig around and see if I can get it working!

Got it working

Cheers !

Sorry to bother you again, @nau, but, if you still have it could you please post your patch here, the sendspace link is dead

Try this, it should be one of the latest versions of it ... sorry for being a bit late.
The file to load is distodrive.pd, it's a kind of workbench allowing to compare the DS-1 and Tubescreamer sims.
Just had a quick try and got two "divide by zero" errors and crappy sound when distortion was engaged (click on pedal to toggle effect on/off), but I'm shure it's easy to fix, as it was a working version, normally
AQf-1.zip
Nau

Great, thanks a lot!