Cycling 74 » Topic: Valve Distortion http://cycling74.com/forums/topic/valve-distortion/feed Wed, 19 Jun 2013 08:38:58 +0000 http://bbpress.org/?v=2.2.4 http://cycling74.com/forums/topic/valve-distortion/#post-61162 <![CDATA[Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-61162 Tue, 10 Jan 2012 19:22:43 +0000 tbland5591 Hi

totally new to max, but im building a guitar processor for a project, im struggling on how to build a distortion effect in max. i would preferably want to create a valve distortion effect using soft clipping. i was wondering if anyone had done this before, please be gentle, like i said im new

thanks

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220398 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220398 Wed, 11 Jan 2012 00:20:17 +0000 leafcutter Welcome, you should really do a search of the form. There are loads of ideas for different distortions.

One of my favourites is the simple tanh~

Check it out

– Pasted Max Patch, click to expand. –

Best,

John.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220399 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220399 Wed, 11 Jan 2012 02:35:00 +0000 Gord Harris http://cycling74.com/2009/01/29/max-5-guitar-processor-part-5/

It is incredible how deep the resources are on this website – check out the community/articles section and keep scrolling and scrolling down and you will find Darwin Gross’s articles on guitar processing. I have not read them all but this would be a darn good starting point!

Good luck! Happy processing in Max!

Gord

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220400 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220400 Wed, 11 Jan 2012 20:10:57 +0000 Peter McCulloch Also, if you go the tanh~ route, consider the following:

- tanh is an expensive calculation. Make a lookup table for x in [-4,4], since it’s -1 / 1 outside that range and you’ll save a ton of CPU. (lookup~) If you have gen~, you might even try doing the lookup with spline interpolation.
- Oversample your lookup inside a poly~ (even if you just use tanh~, do this) to improve the quality and reduce intermodulation distortion.

Good luck!

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220401 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220401 Sun, 15 Jan 2012 04:24:33 +0000 commathe I tried making a lookup table with tanh using a line~ into a tanh~ and then into a record, and it seems to have worked up until I write it to a file. The file it outputs is just 1024 samples of 1.0. Before and after writing it to a table though, the buffer I’m using displays the wave table I’d expect. Can anyone figure out what’s going on?

– Pasted Max Patch, click to expand. –
]]> http://cycling74.com/forums/topic/valve-distortion/#post-220402 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220402 Sun, 15 Jan 2012 19:58:47 +0000 Rodrigo I hadn’t actually tried the distortion in the guitar patch since I’ve used the overdrive~ object before and wasn’t blown away. The usage in that patch is pretty effective (with a filter in between).

I’m surprised we haven’t seen more gen~ stuff for valve distortion, tape saturation and things like that yet.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220403 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220403 Mon, 16 Jan 2012 04:08:10 +0000 Peter McCulloch Here’s the more or less standard approach to generating static functions. You’ll notice that there’s no signal rate stuff going on. (or you could do it with only signal rate functions, but in general, pick one or the other, not a combination of the two because of the potential for timing errors)

– Pasted Max Patch, click to expand. –

@Rodrigo: I think it’s a question of the types of algorithms; static non-linearities are easy enough without gen~, though their quality is not the greatest. The other issue which gen~ doesn’t address explicitly (though Max6 definitely does) is oversampling (via poly~). There’s also a higher learning curve with gen~, since it requires more low-level knowledge of DSP. I’ve been playing around with non-linearities inside traditional filters; tanh works will inside of a reson loop.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220404 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220404 Mon, 16 Jan 2012 08:51:54 +0000 Rodrigo I didn’t realize you couldn’t oversample in gen~. I’ve never really used it as it’s over my head.

That looks great, I’ll have a play with this later when I get home.

edit: sorry for the nooby question here, but how to you implement the lookup table version of tahn? (in terms of adding distortion like the first example posted)

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220405 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220405 Mon, 16 Jan 2012 10:38:25 +0000 commathe Thanks for the annotated touch up Pete! Helped a lot

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220406 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220406 Mon, 16 Jan 2012 13:07:39 +0000 Roman Thilenius “but how to you implement the lookup table version of tahn?”

– use [tanh] and run a series of ascending numbers from 0-1 through it
– use peek~ to write it into a buffer~
– make a buffir~with the same name as the buffer~, see buffir~helpfile.
– like someone said, upsample it in a poly~to reduce the problem between latency and quality.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220407 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220407 Mon, 16 Jan 2012 13:08:38 +0000 Roman Thilenius beg your pardon, buffir~ should read lookup~
^^

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220408 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220408 Mon, 16 Jan 2012 14:41:47 +0000 Rodrigo Ah that’s pretty awesome. I’ve never used lookup~ before.

So at low gain settings this table version of tanh sounds pretty crappy, is that due to the intermodulation/upsample stuff?

Regular tanh seems to fair alright for low gain stuff.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220409 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220409 Mon, 16 Jan 2012 16:43:19 +0000 Peter McCulloch @Rodrigo, you need to build the table with bipolar values; it will sound like crap if you use 0-1 to build your table. (since it’s now bent in a weird way and unipolar. (Use the code that I posted above)

For tanh, use a value from -4,4 to build your table. That’s the point where tanh’s value is asymptotically close enough to -1,1 that you can just clip it to -1,1 after that.

You can scale your input before it hits lookup~ if you like. This will adjust the extremeness of the effect. You should also consider post-gain to adjust for differences in volume. Other typical tricks used are to add a slight DC offset so you get even harmonics as well as odd. You can use a highpass filter to remove the DC afterwards.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220410 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220410 Mon, 16 Jan 2012 17:27:51 +0000 Rodrigo I used your example from above and just added a lookup~

– Pasted Max Patch, click to expand. –

I might just be in over my head code wise, but are you saying to make a -4/4 table, then clip it to -1/1 (literally using clip~)?

I would add a post gain control to bring the volume back in line with whatever the boost was adding.

That’s an interesting trick (adding DC then removing it). So you would just add a [+~] to the audio signal before the lookup~/tanh~ (a little? a lot? or is this a ‘tunable’ thing like gain), then a straight highpass after the lookup~?

Then there’s the upsampled poly trick.

Any other nuggets of distortion creating gold that stops short of gen~ stuff?

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220411 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220411 Mon, 16 Jan 2012 20:56:54 +0000 Wetterberg I think we just need to collectively get one reaaally good gen~ patch with a lot of inlets to tweak stuff and a buffer~ loader thing. That would be an excellent place to start for our own nasty patches as well.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220412 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220412 Mon, 16 Jan 2012 21:39:50 +0000 Rodrigo That would indeed be badass. It’s crazy how complicated tone shaping stuff can be.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220413 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220413 Tue, 17 Jan 2012 01:35:13 +0000 Peter McCulloch Here’s a bit more elaborate of an example:

– Pasted Max Patch, click to expand. –

and TanhVox~:

– Pasted Max Patch, click to expand. –
]]> http://cycling74.com/forums/topic/valve-distortion/#post-220414 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220414 Tue, 17 Jan 2012 10:45:30 +0000 Rodrigo Man there’s a lot to take in in that patch! Thank you!

The start of the signal path confused me until I figured the delay is to probably keep phase alignment with the cross fading input gain (a nice touch!). With regards to that part, wouldn’t running the “dry” signal into normalize flatten it’s dynamic range a bit?
I ran the output of sfplay right into delay and ran the normalized version into the envelope follower and it sonds alright.

The +/- gan thing is really interesting too. I’m wondering if it would be best to control asymmetrically using a couple of scale objects and a single num box.

So much to play with, and this not even into eq/filter territory (I’m tempted to duplicate this whole section and run it in series with a one pole it be middle (like the gtr patch).

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220415 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220415 Tue, 17 Jan 2012 16:07:36 +0000 Peter McCulloch Glad to help. Normalize will normalize it to the highest peak. It’s handy for signals like electric guitar that are pretty stable in terms of dynamic range. It also makes sure that you get some peaks on the envelope follower. You could do this all with gain, but this works much quicker. I like to use asymmetric envelope followers like slide~ after average~ so that you get the decay, but the attack is still crisp.

The reason for the scale with the asymmetry is that I wanted to smooth the discontinuity in gain levels. You can try different crossover ranges (or even no cross-over range) by setting the values for clip~ and scale~’s input range in parallel.

I’d highly recommend the last approach you mentioned. This is the basis of some of the early digital distortion effects. Speaking of which, there was a paper not too long ago (ICMC Proceedings or maybe CMJ?) that summarized a lot of the approaches to digital distortion. It’s totally worth a read. I’d bet some of the early patents have also expired, so Google may be your friend on that.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220416 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220416 Tue, 17 Jan 2012 17:33:18 +0000 Rodrigo Yeah each little section of the patch is a nice little educational resource. I’ll try doing that series/filter thing to get some joy. It’s also more computationally expensive than I had realized, so I might use a more straight ahead version (not unsampled, or smaller table etc..) in my main (already big) patch as I can’t afford to give up 6% just for distortion. Unless I wrap the whole thing up in a poly and mute it when I’m not using it. Hmm.

I’ll have a look around for the paper.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220417 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220417 Tue, 17 Jan 2012 20:11:52 +0000 Rodrigo Here’s the paper:

http://www.mitpressjournals.org/doi/abs/10.1162/comj.2009.33.2.85

And the dude’s thesis:

https://ccrma.stanford.edu/~dtyeh/papers/DavidYehThesissinglesided.pdf

Both waaay too heady for me, and believe it or not, not a single compressed max patch example in either to copy!

Also found this which has more practical info:

http://music.columbia.edu/cmc/music-dsp/FAQs/guitar_distortion_FAQ.html

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220418 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220418 Sat, 18 Feb 2012 22:38:14 +0000 Rodrigo Just bumping this for any new distortion related revelations…

I’ve leaned back towards an overdrive/onepole/overdrive type system since tahn~ distortion seems to have some brittleness to it (or at least how I was implementing it).

Would be amazing to have a convolution-based tape/saturation type effect for more subtle/warming effects. (similar to the tritone digital colortone pro type thing).

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220419 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220419 Sun, 19 Feb 2012 13:44:22 +0000 stkr there are so many ways to approach this, largely depending on your input signal. i have many many of these non-linear saturation type equations stored up over the years – i’ll post some if i get the time.

oversampling is key. and making input / output gains simple eq’s / filters rather than just linear gain controls, and as peter says, including non-linearities in your filters.

the one advantage of using cpu + equations rather than lookup tables is being able to modify them dynamically. attached is a visualisation of this i did this morning, i hope it is interesting. requires max 6.0.4.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220420 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220420 Sun, 19 Feb 2012 16:34:45 +0000 Rodrigo Man that sounds really nice, quite simple too. I’d definitely love to see more of your examples if you wouldn’t mind sharing.

]]> http://cycling74.com/forums/topic/valve-distortion/#post-220421 <![CDATA[Re: Valve Distortion]]> http://cycling74.com/forums/topic/valve-distortion/#post-220421 Sun, 19 Feb 2012 22:37:43 +0000 stkr ok, here are two more.

one is another Tom Szilagyi plugin port, still in progress and needs work. < < single patch

the other is a Julius Smith cubic non-linear saturation curve which Peter McCulloch told me about, so kudos to him. < < .zip folder, abstraction, open the .maxhelp file first

there is no great need for these to be in gen~ – i just happen to be accumulating gen~ things at the moment as i have become obsessed. also, much much easier porting C-code that way. hence, max 6.0.4 required.

also, one more thing – disclaimer: i have no idea what i am doing.

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