Matching time in an audio file to bars in sheet music

Question

I apologize in advance if this is the wrong type of forum to post this question on. Also, I have very little knowledge of music theory so please bare with me.

I have a pdf of some sheet music, and the actual audio file of someone playing the sheet music (with drums in the background as well). I need to add in specific parts of another instrument to this audio file at certain times. These times were given to me as bar numbers from the sheet music.

I have both FL Studio and Ableton Live and am unfortunately having issues translating sheet music bars into "bars" in both DAWs. The sheet music states that it has a 4/4 time signature and is 110 bpm. I put the audio clip into both Ableton and FL Studio and adjusted the settings of the project to match 110bpm and 4/4. The numbered bars that appear in both programs don't match with the bars that appear in the sheet music. Mainly, both programs show around 70-75 bars for the audio file while the sheet music has 121 bars in total.

From what I've read, both Ableton and FL Studio don't necessarily match the bottom part of the time signature for sheet music, so the bars won't always be accurate.

My question is, is there a way to fix this in either program? If not, is there a program where I can set the time signature and BPM and just overlay the actual audio file on the sheet music so I can see what the time is on the bars I need to change?

Alternatively I'm open to other suggestions on how to know where to start on an audio file when only bars from the sheet music are given.

Answer 1

Depending on how the audio file was recorded it may have time deviations from the 100 bpm steady beat you'd need. If it was recorded without a click track, electronic drum, or some other fixed tempo reference, there will surely be jitters that may make it very difficult (or at least demand a lot of work) to perfectly align with a new steady time reference.

The large difference in number of bars is probably due to a different time signature. With the same time signature and if the track is recorded at approximately 110 bpm, the number of bars resulting in the DAW should be approximately the same. But you will still be left with the problem of getting the precise time alignment that you need.

That could be done by manually by error and trial, bit by bit, by time stretching segments of the audio track to fit the fixed tempo, or by adjusting (again, bit by bit) the tempo marking in the DAW. It's a painstaking and difficult work. I think there are some advanced tools used in professional studios that can automatically align a track with a new tempo reference, but I'm not familiar with them nor do I think they would be available for more low budget tools like Abbleton or FL Studio.

An alternative approach would be just to forget about trying to align the bars in the DAW with those in the score and use markers ("locators" in Abbleton) to mark the places where you need to punch in additional content.

Listen to the track carefully while following the score and manually insert markers in the locations where you to need to punch in, giving the markers significant labels (like the bar number in the score or the section name or something like that). Then you can record your inserts while listening to the original track and ignoring the DAW's tempo marking and bar division.