How can I change the number of samples that I want played from a table while the table is continuously looping?
I can use messages like |0 44100( to play that many samples, but can I change this amount that is being looped while it is looping?

[tabplay~] is really better suited for oneshots at normal speed. It's not so hot for looping. For this, you'll want a [phasor~] and [tabread~] combo. Take a look at the attached patch. I didn't have time to test it, but it should work.

http://www.pdpatchrepo.info/hurleur/loopsection.mmb.pd

thanks a lot
this is very helpful