----- Original Message -----
Sent: Wednesday, September 28, 2011 8:23
Subject: Looper crossfade advice
I've been making some changes to my iOS looper Loopy, to try to make loop
transitions smoother, and I'm hoping to get some advice on crossfading
Before, Loopy would record for the exact duration requested (the "clock"
length), and then microfade to silence at either side of the boundary, over
something like 128 frames. It avoids any click at the boundary, but
doesn't sound particularly smooth - in fact, it introduces a hole at the
So, now, my current strategy is to record for a fraction longer, both
before and after the actual recording starts and ends, so that there's some
extra audio (2048 frames, or 0.046s) at the start and end to overlap and
crossfade (using an equal power x-fade). So, prior to the crossfade, we
have 2048 lead-in frames, then the loop recording, then 2048 lead-out frames.
Then I overlap those frames, like this: http://atastypixel.com/duyoq
This sounds great, and super smooth, but a user was commenting that he
can clearly hear the following downbeat after the recording of a loop.
It seems to me like this might be a necessary evil - we have to have
extra audio to overlap, otherwise there's no other choice than to either have
no crossfade, or to fade to silence, both of which are undesirable.
So, I was wondering - is there an alternative solution, to getting nice
smooth crossfades at a loop boundary, without recording outside the loop?
What do hardware loopers do here?
Thanks heaps =)