Need help with pitch or freq shifting an acoustic signal

Acoustic Interloper

After getting MAX/MSP to generate some tones to the dac with no problem, I tried inputting a mic through pfft~ through gizmo~ to so a simple pitch shift as outlined in the msp manual, then out to the dac. There is no discernable pitch shift -- it sounds like the original signal. If I break any of the connections along the signal path, the signal stops, so it appears to be flowing through my patch, but there is no pitch shifting.

I tried replacing the pfft~ -> fftin~ -> gizmo~ -> fftout~ subpatch with a simple freqshift~ up at the top level beteen the adc and dac, and this likewise has no discernable effect.

On the other hand, if I insert a lores~ filter, it definitely filters according to the cutoff freq. So, my signal path is being used, but it seems like no pitch shifting or frequencey shifting works. I checked the DSP IO settings, they seem OK. Any suggestions for a newbie to MAX/MSP? This is MAX/MSP 4.6. Thanks.

EdisonRex · Posted: Mon Jan 21, 2008 1:04 am Post subject:

want to post the patch? It's probably your arguments but I can't tell without looking at the patch.

Acoustic Interloper · Posted: Mon Jan 21, 2008 10:36 am Post subject:

EdisonRex · Posted: Tue Jan 22, 2008 4:35 pm Post subject:

I haven't forgotten about this. I made your patch but I need to mess around a bit with sources. Just trying to avoid firing up the whole studio over it. Soundflower isn't helping.

Acoustic Interloper · Posted: Tue Jan 22, 2008 5:16 pm Post subject:

Thanks. Job hunting and my wife's newly herniated disk have been keeping me busy, but my plan is to dig through the manuals and figure out how to dump the frequency domain info for a window, and then do a "before" and "after" on the gizmo~. Any day now.

Take care.

cbm · Joined: Oct 25, 2005 Posts: 381 Location: San Francisco

Doesn't the gizmo~ help file illustrate exactly what you are trying to do?

Acoustic Interloper · Posted: Wed Jan 23, 2008 10:12 am Post subject:

cbm · Joined: Oct 25, 2005 Posts: 381 Location: San Francisco

I patched up your patch (more or less), and it worked as expected. Here it is in two parts. First the pfft part. It should be called GizmoShift.pat

Acoustic Interloper · Posted: Wed Jan 23, 2008 12:26 pm Post subject:

cbm · Joined: Oct 25, 2005 Posts: 381 Location: San Francisco

Max has a "New from Clipboard" command that will work with these snippets. Copy one of them, then go to Max, and select "New From Clipboard". This will create a new patcher.

Acoustic Interloper · Posted: Wed Jan 23, 2008 4:48 pm Post subject:

Adding a "loadbang" to my original patch did the trick. Thanks again! It looks like I'd better start reading those manuals.

This was my second patch. I drove the first from a Python program, and started out by figuring out MAX's packet protocol for numeric lists across UDP. No problems with that one Exclamation

Five string banjo across this patch sounds like playing bed springs Shocked

EdisonRex · Posted: Thu Jan 24, 2008 2:11 pm Post subject:

OK, I've learned something too.

Interesting. I had it right two nights ago, but my audio path (outside of Max) was very silly. Now i have this patch playing. Interesting.

By the way, thanks Chris.

cbm · Joined: Oct 25, 2005 Posts: 381 Location: San Francisco

My pleasure.

By the way, the official Max forum has a lot of good discussions, although it can resemble a fire hose at times. http://www.cycling74.com/forums/

-C

EdisonRex · Posted: Sat Jan 26, 2008 10:49 am Post subject:

The problem with the official MAX/MSP forum (or the mail list, which I am subscribed to) is that it is somewhat uncompromising. I do not find it to be a particularly friendly place.

That said, it is a good resource, if you can master the search function.

cbm · Joined: Oct 25, 2005 Posts: 381 Location: San Francisco

If, by "uncompromising", you mean that it's not such a good place for beginner's questions, then yeah, it can be a little rough.

All you really have to do there, though, is show that you've done some homework, before asking questions. In particular, one thing that sets the list off is the flurry of "please do my assignment for me" questions that show up at the end of the semester.