Slow Down Music (Tempo Change) With Audacity Audio Editor

Video demonstrates the use of Audacity to change tempo... which for most people means to slow down a song or music. Tempo change in Audacity is then compared tempo change in Song Surgeon.

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Closed Caption:

I have a copy of audacity opened and you
can see it on my screen here and today
we're going to talk about using audacity
for tempo change that is to slow down a
song or an audio file and to speed it up
a lot of people use audacity for a lot
of different reasons and it is a fairly
decent audio editor but people also use
it and build into it are the abilities
to change pitch and tempo there are some
problems with doing that in audacity
because of the technology that employees
in the fact that is you do it you
introduce audio artifacts IE distortion
let's take a quick look first of all
have this song open it is an organ song
and we're going to listen to this 15
second segment of it here at the normal
temple without changing the speed of the
song it also lets listen
okay you've heard 10 seconds of it you
can hear that it sounds nice as it
should its unmodified the WAV file has
not been changed and therefore there it
should playback well and it does now
let's go ahead and let's apply a change
and we're going to change the temple and
we're going to change it lets say by
four percent and I've got that set up
here so a tiny amount so let's say
you're going to you want to change the
temple slightly because you want to
re-record this or exported and save
those changes so you can use this file
in some type of performance setting so
you're not talking about a huge tempo
change here relatively modest temple
change let's apply it now first of all
this little screen that flashed
something I want to just mention to you
and that is that you can't change tempo
on the fly or real-time with this you've
got essentially stop what you're doing
define the area that you want to change
and then apply the change and then once
you've applied the change and go back
and play it and listen to it and the
ability to do it real time so you can
click around and basically change it
from 52-42 3292 whatever you want real
time is very valuable and you're going
to see another program we're going to
show you in just a minute that is able
to do that so that's one thing that's
somewhat problematic but more
problematic is the fact that here with
just a four percent change in Temple
let's go ahead and listen
but listen for the flatter again we
changes only by four percent but there's
a flutter or a wobble introduced already
after four percent so let me play it
again and listen for that
now to be fair i should point out that
on some songs you can do a four percent
change and you may not hear any
distortion but the point is that on some
songs that you do and clearly on any
song as you change the temple more
drastically you introduce an increasing
amount of distortion to the point that
it becomes something that you can't
really use because you can't hear what's
being played because of all the
distortion with that it's a brief
introduction to audacity and how you can
use it to slow music down or to change
the tempo we're now going to shift gears
let me load another program in my
computer and let's take a look at that
ok and the program we're going to
compare audacity to is called song
surgeon song surgeon has been around for
four years and the original version of
song surgeon used the same exact sound
engine that audacity has but when we
release this newest version version 3 of
song surgeon we did so with one of our
primary development objectives being to
replace that sound engine with something
much better and indeed that's what we
have in this newest version this new
sound engine that we have gives us
nearly flawless audio even when you play
it back at it significantly reduced
temples or change speeds so let's go
ahead and listen first of all here's the
normal speed
yeah
that is the original let's go ahead now
and let's listen to it at a reduced
speed as we listen to it at this reduce
speed watch what I'm going to do I'm
going to change in real-time something
audacity could not do the temple and you
can listen to it at these various
temples in this case we're going to
reduce the speed we're going to slow
down the music but you can hear it as it
does this real-time and you also should
listen for distortion see if you hear
any of the flutter or the wobbling that
you heard when we used audacity
ok as you can see I've slowed it down to
forty percent and there is no distortion
at that level
no fluttering like we heard an audacity
and again to summarize here real quickly
the main to differences are that you
don't have this distortion because we
have a much much better sound engineer
you can do a real-time which is very
important in the last thing which i
haven't mentioned is depending upon what
you're using song surgeon for we have
two different algorithms that we use for
changing temple so if you like what you
see of song surgeon you might consider
going to our website i will post a link
on it here momentarily and from that
link you can download a fully functional
for our working demo in which you can
try the slowdown music function of the
tempo change function yourself
thanks for your time today by