adding snare drum starting with one beat

Using Audacity 2.0.5 in Windows 7 Ultimate.
I have an audio track that’s missing a snare drum on the off-beat. I downloaded a sample snare hit, imported it into Audacity and lined it up to it’s first occurrence by ear.
Then I Duplicated the snare sound and pasted it onto the end of the original one giving me two snare hits.
Next I repeated the above procedure pasting 4 then 8 then 16 beats and so on until I’d covered the entire length of the track.
Then I spent ages tweaking the tempo until I felt the snare track was synchronised. This wasn’t easy due to several minute timing differences in the original music track. So I spent another hour or two playing both tracks together and inserting or deleting a few millisecond’s silence here and there to drag the snare track back into sync.
By now I expect several Audacity aficionados are shaking their heads in sorrow. Yes, I know there has to be an easier way than this. Can anyone show me that way?

I was sure you were going to complain that you exported the work and all the timing controls vanished.

No, that’s pretty much it. Particularly in a long piece with manual timing from live performers, the rhythm is going to wander and you just have to follow it, just like a real drummer – except in reality, the rest of the performers are following him.

Sometimes you can put groups of snares on their own track one above the other. That will avoid them interfering with each other – like change the spacing between the first two hits and the entire rest of the song changes. WIth separate groups, it will only change up to the first track break.

I’m assuming you did this on separate tracks, right? You don’t have to surgically Generate > Silence to get the spacing. You can use the Time Shift Tool to push audio sooner and later on a timeline. The downside of that is the spacing is “magic” and the only way to get a final show is to Export one or Save a Project. You can’t Export the drum track by itself.

Projects, of course, don’t play anywhere but in Audacity, but it is a good way to save the show in pieces so you can move it around later if you want. Audacity Projects do not save UNDO.


By now I expect several Audacity aficionados are shaking their heads in sorrow.

Only that if you spent enough weeks on it, you could have hired/found a drummer and reshot it.

If the music was made with real instruments played by real people, then this is tricky because the tempo, hence the spaces between beats will vary to some extent during the course of the music.

If the music was “sequenced” in software, then it can be somewhat easier because the timing is likely to be consistent.
If the exact tempo is known, then easier still.

The first task is to determine the tempo.
Actually we want this a the length of one bar (in seconds).

The best way to do this is to select a number of bars, look up the duration in the Selection Toolbar (Audacity Manual) and divide the duration by the number of bars selected.
For example, if (exactly) 16 complete bars are selected and the duration is 31.22 seconds, then the length of one bar is 31.22/16 = 1.951 seconds.

For greatest precision you can measure the length in “samples”.

Create one bar with the snare drum as accurately as possible.
Select the snare drum and, use the Selection Toolbar to extend the selection to 1 full bar duration (as previously calculated).

Then use the Repeat effect (Audacity Manual) to create the additional bars.

Depending on accuracy when calculating the bar length, the beat may gradually drift out of sync. If it does, then find the last bar where the synchronisation is acceptable and delete all the subsequent bars. Then past the first bar as the next bar and align it carefully with the music track. Repeat that bar as necessary.

Some good responses here. I’ll follow those links, Steve, next time I need to fabricate a drum track. Hopefully they’ll make things a bit easier.

In one sense I’m disappointed to find there’s no easy, mechanical way to do this. But then the very fact that real musicians will tend to drift, tempo-wise, is what makes live music great compared to the plastic feel of some synthesised stuff. Thanks for your submissions, guys.