How to fix rushing / stabilize tempo?

[austinjb555]

Hi, I have 2 marching band recordings I would like to play together- a drum cadence over a chorale.

However, the band rushes in the choral and I'd like to make the tempo stay the same throughout (~133BPM), and also edit the drum cadence to play at around 133. The chorale starts slow and speeds up, and the cadence is fast, and possibly changes tempo a little, but drumline is good at keeping tempo.

How can I align the tempos to the same tempo and so that the beats are aligned throughout the whole song?


Thanks,
Austinjb555

[steve]

It's quite tricky to get it right, but the tools for the job are either "Change Tempo" or "Sliding Time Scale / Pitch Shift"
The latter effect works very slowly.

The first thing to do is to find the points where the tempo changes, and work out exactly how much the it needs slowing down at various point.
As the change is likely to be only a few %, the easiest way will probably be to split the track into sections and make changes to the tempo in each section. This will create a gradually "stepped" tempo effect, but as long as the steps are only about 1 or 2 % it will probably sound smooth enough.

For example, if you have a one minute section that gradually speeds up by 4%, then split it into 4 seconds and adjust each 15 second section so that they all have the same tempo (you would probably only adjust three sections and adjust them to match the fourth).

[austinjb555]

Ok, well it just doesn't seem to want to work for me. Can you maybe give it a try?
This video will show when the drums come in:
http://lehsbands.smugmug.com/Marching-T ... h2uFG-A-LB

These are the mp3 files:
http://www.2shared.com/audio/bBzjl2HI/10_Track_102.html
http://www.2shared.com/audio/7OOM_jPF/1 ... ated2.html

[steve]

The drums need to speed up by an average of about 3%.
Because the drums are not "pitched" instruments, you can use the "Change Speed" effect. (with pitched instruments you would notice the pitch change when using the "Change Speed" effect, but for non-pitched percussion this effect is not really noticeable.

Even though the drums are keeping a more strict tempo than the melody, the sound quality is better if using the change speed effect on the drums than using the change tempo effect on the melody. I think it also give a more convincing "performance" as the tempo changes in the melody are expressive changes rather than bad timing.

I'm not sure exactly where the drums and melody are supposed to line up (the melody is longer than the drum track) so I started near the beginning.
1) Line up the start of the drumming with the place in the melody that it should start.
2) Apply 3% "Change Speed" effect to the entire drum track - this will bring it close to the correct speed.
3) Play both tracks until you hear the drums and melody drifting apart, then stop the recording with "Shift + A" (this will keep the playback cursor at the position where it stopped.
4) On the drum track (only the drum track), use "Shift + left mouse button" to drag a selection from the current cursor position back to the last place where it sounded synchronised with the melody (to the left). If the drums need to play faster in this selection, use Change Speed with a positive value of about 1%. If they need to play slower, use a negative value.
5) Continue from where you have got up to until they drift apart again. Continue in like fashion until you reach the end.


Here is the first part of the piece that I have adjusted in this way:

Salvation is Created mix.flac

(1.7 MiB) Downloaded 111 times

[austinjb555]

Thanks, I got it pretty close, here it is:
http://www.youtube.com/watch?v=CI5qjKZjtRQ

[steve]

Excellent
It gets a bit tricky around 43 seconds and there's a noticeable pitch shift at about 1 minute, but that's pretty close, and what excellent stirring music.