Frequency Crossfader / general Xfader question

Nov 1, 2011 at 9:40pm

Frequency Crossfader / general Xfader question

Hi guys,
I’m trying to make a patch that would allow me to crossfade different frequency bands between two or more sources of audio. In hardware, this has been done in the Pioneer DJM-2000 (, with an excessive 7 bands, and the Behringer DDM-4000 (

However, I’m having problems even figuring out basic crossfading, and I’m surprised there isn’t just a simple object for it like there is in Jitter.

How can I achieve this? All help is very much appreciated!
Thank you,

Nov 1, 2011 at 10:33pm

I had a couple minutes spare and made a video on how to do this with fft:
To cross-fade between 3 sources you could make 0.5 the “on” value for the third source. The other stuff involved in this would be math.
Maybe this isn’t your preferred method (you could just use filters), but it is kind of a cool idea.

Nov 2, 2011 at 2:44pm

Hi Baz,
thank you, that’s a fantastic video.
eventually, what I’m trying to get out of it is 3 sliders that each fade between one frequency band on two or more audio sources. maybe this is just a question of attaching sliders to the axes of that graph or so, but it’s probably not that simple.

since I’m still new to this, could you help me figure that out? and what is the advantage of your method over using filters (which I’m also not sure how to do)?

thanks again!

Nov 2, 2011 at 3:40pm

simple abstraction for crossfading are [M4L.bal1~] for mono xfade and [M4L.bal2~] for stereo.

An easy (non fft) way to do what you want would be to use the [fffb~] object and then the xfades above. I’m gonna try it out later.

Baz another cool tutorial – very good of you to answer with a video. I am struggling with the fft stuff but looking at your video’s I am much more comfortable with the language and objects used and the kind of thing you do – so thanks :)

Nov 2, 2011 at 6:16pm

hi Grizzle,
that sounds exactly like what’ I’m trying to do – could you elaborate on that, or maybe show me a simplified patch?
thanks so much!

Nov 3, 2011 at 5:39pm

I really shouldn’t be encouraged. Anyway, here’s a video using moving windows to crossfade between multiple sources:

I tried using fffb~, but I think resonance makes the filters sound a bit rubbish for this application.

I also tried using normalized random values for fft bins, but that didn’t sound very interesting. There is a gen~ thing at the end of the video that shows what I was trying to do with that.



Nov 4, 2011 at 3:02am

I gave it a go… it’s not so bad if the Q is set to 0 – sounds ok to me. unfortunately it is of no real use to me until M4L supports multichannel – does anyone think this will ever happen – could it happen?

– Pasted Max Patch, click to expand. –

Thanks Baz another vid… going to watch it now :)

Nov 4, 2011 at 6:48pm

Hi Grizzle,
I actually ended up coming up with pretty much your exact patch, see attached screenshot. however, I still have to tweak the filter bands a bit, but your version with just the simple division into three equal ones sounds surprisingly good. with the Q at 0, is the whole frequency range being covered? I definitely don’t want any sound coloration.

Baz, great video as usual. could you maybe post the code for that?

thanks so much, guys!

Nov 4, 2011 at 6:49pm

Edit: see attached.


  1. Screenshot20111103at15.40.12.png
Nov 23, 2011 at 4:57am

Sorry for the slow response to the request.

The patch:

– Pasted Max Patch, click to expand. –

The pfft~ jive:

– Pasted Max Patch, click to expand. –

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