Yes, and it's not recaller, though it does help a little. It does this with every OS release, every carrier, regardless of installed apps. It's just the people notice when something is affecting audio.

If you find this at an annoying level, try to switch to WAV, which puts a lot less stress on the CPU. Drawback being, files are huge. I transfer and encode up to 700M a week.

There's a reason Phone app locks CPU at 600 MHz for the duration. Also, I understand it has all kinds of priorities. Still fails, it sometimes takes seconds for it to die down from the choppiness and buzzing. Overclock doesn't help much. I did notice, however, that at 900 MHz it tends to only do this when answering, rather than in the middle of calls too.