Download link: http://www.singularsoftware.com/levelator.html
From their website:
What is The Levelator?
Do you believe in magic? You will after using The Levelator to
enhance your podcast. And you'll be amazed that it's free, now even for
So what is The Levelator? It's software that runs on Windows, OS X
(universal binary), or Linux (Ubuntu) that adjusts the audio levels within
your podcast or other audio file for variations from one speaker to the
next, for example. It's not a compressor, normalizer or limiter
although it contains all three. It's much more than those tools, and
it's much simpler to use. The UI is dirt-simple: Drag-and-drop any WAV
or AIFF file onto The Leveler's application window, and a few moments
later you'll find a new version which just sounds better.
Have you ever recorded an interview in which you and your guest ended
up at different volumes? How about a panel discussion where some people
were close to microphones and others were not? These are the problems
the post-production engineers of Team ITC
here at The Conversations Network solve every day, and it used to take
them hours of painstaking work with expensive and complex tools like
SoundTrack Pro, Audacity, Sound Forge or Audition to solve them. Now it
takes mere seconds. Seriously. The Levelator is unlike any other audio
tool you've ever seen, heard or used. It's magic. And it's free.
When we developed the IT Conversations component-based show-assembly
system, we realized all the components had to be of the same loudness or
the results would sound awful. We limped along for many months using
the RMS normalization functions in various applications, but the results
weren't satisfactory and it required tools and skillsets that some of
our post-production audio engineers didn't have. One of our best
engineers, Bruce Sharpe, offered to write a standalone software RMS
normalization utility, which we've been using as part of our production
system CNUploader since 2005.
The CNUploader's normalizer acts similar to an intelligent RMS-based
compressor/limiter combination, and it therefore affects primarily the
short-term (transient) sounds and the long-term overall loudness of the
file. It doesn't make the kind of adjustments that a skilled audio
engineer can perform in software or at a mixing console, riding the levels up and down to compensate for medium-term variations.
There are some hardware devices such as various AGC (automatic-gain
control) components that can do moderate leveling, but since they have
to operate in real time (i.e., without look-ahead), they can't
do much. And they aren't cheap, let alone free. Even a skilled human can
only react to changes unless s/he is lucky enough to be present during a
recording session and can use visual cues to anticipate coming
variations. Software can do better by performing multiple passes over the audio, generating a loudness map of where the volume changes. (It's not actually that simple, but the metaphor is helpful.)
Bruce, with help from his son, Malcolm, had proven that he knew how
to tackle these problems in ways that no one else anywhere in the
audio/software industry has done to date. So we asked him, "Bruce, do
you you think you can write a leveler that corrects for
medium-term variations in loudness instead of the short-term and
long-term variatons processed by compressor/limiters and normalizers,
respectively?" Bruce and Malcolm took on the challenge, and eight months
later we began testing The Levelator.
You'll believe in magic.