How do I slow down a recorded session ("rallentando")?

Getting Stuff Done How do I .... ?
#1

Hi all!

I need to change the tempo metering while playing a recorded session with 23 (!) tracks.

The tempo started with 95 bpm and should go down to 60 or less (I have to check the final effect).

It seems there’s no way to accomplish this or it is not so intuitive (for me, at least).

I can change the tempo in the said measures, but while listening nothing happens.

Could please somebody help me?

TIA,
Ric

#2

But… wouldn’t Alsaplayer also change the pitch of the sound while slowing down the tempo?

#3

Would the pitch remain unaltered?

The problem is I have 23 (!) tracks (a big band recording) so maybe I should first mix them up in a stereo track then try and do the trick, isn’t it?

#4

It will change (lower) the pitch.

#5

the “tempo” in ardour is the tempo of the click track. Just a convenient / conventional way to measure time in music.
To accurately slow down a performance that is already recorded, you would have to use the “time stretch” tool on lots of short regions and stretch them increasingly, to get the “rall” effect. Sounds a tedious thing to do and will probably sound crap if not done with extreme precision.

#6

@ric0751: i am not 100% sure precisely what operation you want to perform, but if you really are trying to manipulate existing audio as if was MIDI data - stretching and shrinking it in arbitrary ways along both time & pitch axes, then ardour is not the tool for you, and for now, linux is not the platform either.

#7

We do not have any applications on Linux that I am aware of that can do “elastic time” in the way that Live and several recent releases of other DAWs can do. Ardour and other Linux apps can certainly do time-stretching, but this is very different from the kind of audio-as-putty approach now possible in those other tools. Its not that we don’t know how to do this, but as far as I know, there are no applications that include it right now.

#8

Alsaplayer might be what you’re looking for.
Export your song to a wav, load it in Alsaplayer and connect the outputs to the input of an Ardour stereo track. Then use Alsaplayer’s speed control to manually decrease it (click on it and use the scroll wheel) while recording.
The problem might be finding the exact tempo as the speed control works as a percentage of the original speed. It’ll also affect the quality of the sound for obvious reasons.

#9

Sorry, how do you mean ¨linux is not the platform either (at the moment)¨? Because of the tools/applications available at the moment? Or platform-specific?

Roald