RE: MAX/msp question

["Jeff Larson" <jeff.larson@sailpoint.com>]

From: Per Boysen [mailto:perboysen@gmail.com] 
> I wonder if it would take a lot of time to make a looper like Mobius  
> in MAX?

I'm certainly not a Max expert but I feel confident in saying that you
cannot duplicate *all* of the Mobius functionality using just Max
built-in components (or the things you're going to find in the
forums), you would have to write most of it in C or C++ as a Max
"external", and at that point you're basically just writing a
VST plugin.

Now, before the Max fans start firing off impassioned responses
claiming MAX CAN DO ANYTHING DAMNIT!!!, take a few cleansing breaths
and go skim the Mobius and EDP manuals.  Trust me it can't be done,
and even if it were theoretically possible it would take more time and
energy than any sane person would want to expend.

A more interesting question is whether Max can do exactly what you
want.  This may be quite possible.  Max is not very good for building
complex general purpose systems that meet many people's needs, but it
is fairly good at building limited systems that work exactly the way
you want them to.  

> I guess it must be possible to set up a loop with overdub layering and
> feedback control in MAX? I've heard normal tape-style delays in MAX so
> it must be possible!

Overdub with feedback alone is relatively easy.  Where tape-style
looping gets hard is when you want to implement multi-layer undo.  At
minimum you have to save copies of each pass of the loop and provide a
UI to select them.  Where it starts to get really fun is supporting
the concept of "seamless overdub over the loop point".

A common technique is to leave overdub on and play a sustained tone
that crosses the loop boundary.  In order to support undo you have to
generate a new layer *however* you must also avoid a fade-to-zero at
the edges of the two layers or else there will be a "bump" at the
start point during playback.  This is difficult for loopers that
implement layers as autonomous tracks that can be mixed independently.

If for example you reduce the volume of the second layer's track to
zero, there will be a click at the end of the first layer's track
because the wave form that was being played immediately after the end
of the first track is now gone.  There are several ways to solve these
problems, but I cannot imagine implementing them by drawing pictures
in Max.  But I look forward to the Max-o-philes telling me I'm wrong :-)

Jeff