Jun
13
Written by:
masterblogger
6/13/2011 6:12 AM
Enabling Warp allows stretching clips in Ableton Live; you can choose from various algorithms (Beats, Tones, Texture, etc.) that are optimized for different types of audio.
I’ve recently discovered the
benefits of audio files that can
stretch to match a project’s
tempo changes, but I’m trying to
sort out the different stretching
technologies—REX, Acid, Apple
Loops, DSP-based, and so on.
Which gives the best stretch
quality over the widest range?
KEN HENDERSON, JUPITER, FLORIDA
VIA E-MAIL
It depends on the
source material. REX
files “slice” percussive
parts into individual
hits, so they work well
with drums (which
have short, discrete
hits), and can speed
up over a wide range.
However, slowing down
creates gaps between
slices. With short
percussive sounds
this isn’t a problem,
but if something like a
cymbal sustains over
multiple slices, there
will be gaps in the
cymbal sustain. Making
your own REX files
requires Propellerhead
Software’s program
ReCycle.
Acidization usually
speeds up well, but
slowing down more
than 10 to 20% can
give a grainy, echo-ey
sound quality. Editing
the Acidization markers
applied to files may
improve stretching
for specific tempos,
but this process can
be done only in Sony
Acid or Cakewalk Sonar
(both of which can
also create Acidized
files). Apple Loops use
a process similar to
Acidization; Logic Pro
includes a utility that
simplifies creating your
own Apple Loops. (The
June 2008 “Power App
Alley” in EQ magazine
shows how to do this;
visit emusician.com
for more information.)
Note, however, that
creating stretchable
files of any type is an
art that takes practice
to master.
Doing “offline”
stretching with DSP
can give surprisingly
good sound quality
with modern algorithms
like those from iZotope
and zplane, but unlike
REX, Apple Loops, and
Acidized files, they
won’t adapt to realtime
tempo changes in
your host.
Finally, some
programs have
proprietary ways to
stretch files (Pro
Tools’ Elastic Audio,
Cubase’s Hit Points,
Ableton Live’s various
internal stretching
algorithms, etc.).
However, most sample
library files provide
REX, Acidized, and/or
Apple Loops formats;
use whichever your
host can import.
THE EDITORS