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Convolution reverb without externals?

March 27, 2013 | 6:46 am

Im working on a Space Echo like device, and the echo/delay part is done, but I would like to implement a Spring Reverb to the end.
I’ve tried to bild my own, but sounds weak :(

I think the only way is to build a simple convolution reverb, very very simple, with a built-in IR from the Space Echo.

I’ve done one, but I’ve used Alex Harker’s externals to it, and because my emulation could be a commercial product, I wont use other peoples externals on it. (In the other hands, I don’t know how to build externals, so I can’t make my own :( )

Is it possible to create a very simple convolution reverb without externals?


March 27, 2013 | 1:17 pm

…so how would this differ from the convolution reverb that comes with max for live? (Apart from the Harker stuff)

just wondering.


March 27, 2013 | 1:41 pm

The problem with that one :

- to complicated. My device would be an old analog emulation, without any extra features,
- I would like to sell my device, and won’t create a "copy-paste" version of the actual one…


March 27, 2013 | 7:12 pm

i believe you can do convolution with the pfft~ and fft~ objects but i also believe that there’s a reason why Alex Harker built his externals for it.
For a start, check out http://alycjones.files.wordpress.com/2012/04/how-to-convolve-in-max.pdf


March 28, 2013 | 12:18 am

Max can do real-time convolution quite easily with the standard max objects, but the OP wants IR convolution (convolve with a static buffer) to create a reverb, which I think is harder to do in max…

I found some screen shots of a patch:
http://www.pescadoo.net/annexe/max/convolver/pfft-convo-ovad.html
and relevant subpatchers:
http://www.pescadoo.net/annexe/max/convolver/blocks.html

http://www.pescadoo.net/annexe/max/convolver/pfft-convo-unit.html

from back in the days when max had rectangular message boxes

It looks like it would do what you want (reverb times of no more than 65536 samps, about 1.5 seconds)


March 29, 2013 | 9:50 am

just so you know, the 3-clause bsd license of the hisstools does not forbid commercial use. I am not talking about the M4L device, but the objects behind them available on http://eprints.hud.ac.uk/14897/ read the license, as long as you spell our name right, you’re fine. Convo with pfft is very inefficient and highly limited…

p


April 9, 2013 | 11:45 pm

Hi snaper,

As PA says the version of realtime convolution we put in the HISSTools stuff has no limitations for commercial usage. FWIW, the reason for the license on my external set is that various externals there use code that is not mine and has restrictions.

I hope to remove this restriction by replacing the relevant parts of my external set when I have time, but actually there is nothing in the convolution externals of this nature.

The HISSTools multiconvolve~ object adds windows support, however, and is easier to use, so I’d advise you use that.

Alex


May 8, 2013 | 1:00 pm

Dear Alex and Pierre, it would be great if your objects could be part of the standard Max distribution! After all they are already in the m4l standard distribution (inside the convolution reverb devices)
That way we will be sure they’ll be always compatible with future versions of Max.
Would it be possible?

Thank You for considering
Maurizio


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