Problems Creating Tempo Maps

[bayswater]

I've tried many times in the past to create a tempo map in DP from a recording of a freely first played track, and then use it in a sequence to keep the rhythmic feel of that first recording. It has never worked. I always end up spending a long time with Adjust Beats to get a usable map. From the manual, it seems clear that I should be able to get a usable tempo map without extensive use of Adjust Beats.

I'm hoping if I describe exactly what I'm doing, someone can tell when I'm doing wrong, or whether I'm looking for something DP doesn't do. For simplicity, I did this particular test with a recording of a cowbell freely played at roughly 80 bpm with no click track for about 90 seconds.

Steps:

1. Open the soundbite in the waveform editor, click in the waveform and use the i-beam tool to select the whole soundbite.
2. Select "Beats" and in the beats menu, select "find beats in selection". Beats are added to the display, exactly at the onset of each cowbell hit, as expected. Close the waveform editor.
3. Select the soundbite in the SE and select "set sync point at first beat" in the Audio menu. Drag the soundbite so the sync point lines up at 2,1,1 in the timeline.
4. With the soundbite still selected, go to Audio>Soundbite Tempo>Analyze Soundbite Tempo
5. Set the tempo control to the conductor track.
6. Go to Audio>Adjust Sequence to Soundbite Tempo

A tempo map appears in the tempo track. There are small tempo changes every few bars to the end of the soundbite.

I expect at this point, the cowbell hits should be closely aligned to half notes or quarter notes on the timeline. This is true for the first few bars: in this case they align closely to half notes, but then it starts to drift. After about 30 seconds the drift is significant, in no particular direction, and by the last few bars, there is no apparent alignment between the cowbell hits and the timeline. It never drifts as much as an entire half note, but the tempo map is not usable to record more tracks.

Am I missing some crucial step? Is this function not designed to create tempo maps for more than a few bars? Is it only sensitive to very small tempo variations?

I'd really like to nail this and get a quick repeatable process to create tempo maps.

[FMiguelez]

I never use that method.
Wouldn't you need to quantize them somewhere during the workflow?

Have you tried the Record Beats command instead? As I know you know, this tempo map will only be as accurate as your tapping, but you could use Adjust Beats to correct offenders afterwards.

[bayswater]

I don't understand why you would have to quantize using this method. I thought the point was that DP would use the beats in the Soundbite to figure out where timeline points are supposed to be, and then adjusts the tempo so those points line up.

I have used the tap tempo methods. It does work better, but surprisingly, not as well as I would expect. I'm looking for something that can be done that relies more on DPs internal processing.

[Killahurts]

I have used the tap tempo methods. It does work better, but surprisingly, not as well as I would expect. I'm looking for something that can be done that relies more on DPs internal processing.

+1

I use the Tap Tempo method myself, because of what you describe. I've actually gotten pretty good at it over the years, as it is an acquired skill to do it right. But I do wish I could just hit one damn button.. I mean, it's 2012 already.

[bayswater]

I'll try tap tempo and see if that gets me further faster. Adjust beats eventually works, but it sometimes does some odd things.

If anyone has been able to get good tempo maps from long soundbites using just the tools mentioned above, please let us know how you did it.

[FMiguelez]

It SHOULD definitely work the way you describe, BW.

Same thing happens with the Extract Tempo From MIDI command... It almost works, but not quite...

Maybe it's time to contact MOTU about it? I did alert them about the above command, but never heard back from them...

[bayswater]

Yes, I've tried the "extract tempo from MIDI" using a drum hit I recorded over the soundbite. Result made no sense at all.

I'm finding the most reliable method is brute force: Record a MIDI click manually at the start of every second bar of the soundbite, starting at bar 1, then use Adjust Beats to drag the same bars in the timeline points to the correct position on the soundbites. Then fine tune the positions to avoid any overly abrupt tempo changes. Tedious, but gives a usable result in a predictable amount of time.

I agree a question to MOTU might be in order. When I'm done this song, I'll use the recorded click track to create a tempo map as outlines in the manual, and ask why it doesn't work.

[Booter]

I use the exact technique that you described but I do one more step before adding the file to a track. I always listen to the track in the waveform edit with click turned on. That lets me listen to the tempo with the track and see if there are errors. Once I hear the click drift from the track I instantly stop playback and look for a beat where the tempo is wrong.
I think there's a way to get it to correct the errors using the tempo tab but I've found that it's a lot easier to correct the tempo by just using the mute tool to turn off a beat. Then I re-run the analyze tempo step and repeat the process. There's usually only one or two errors and the tempos are always right on a beat so turning off that beat just makes DP skip the bad tempo.
Once I've corrected any tempo errors then I set the sync point and add the file to my sequence and proceed with the other steps.

[bayswater]

Booter, thank first of all for pointing out that the mute tool can be used on beats. Sometimes the obvious doesn't occur to me. I've been using the beat on/off command in the waveform editor.

Second, your suggested solution works great, so thanks for that too. Having tried your approach, I'll add that with the soundbite window set to Tempo, rather than Beats, it is simple to drag the beats to the timeline positions. Easier than using Adjust Beats in the SE.

Still, I find it odd that in my simple trial, example where the soundbite consists of nothing but cowbell hits, reasonably evenly spaced, that DP didn't use the transient of each hit as a bar or beat position to calculate tempo, and instead usually chose spots just before or after these hits. I can understand that happening with more complex music where there are a lot of other transients.

[Dan Worley]

I've found that DP likes a hand clap better than a cowbell, though adjust beats is always needed at some point.

[bayswater]

Yes, that's right. The Click preset on the K2000 worked better too, but a lot of manual tweaking is still required.

I'm surprised this doesn't work better. A long time back, I had a MIDI only sequencer called Metro (the audio + MIDI version is still around). You could arm a track, play a passage of a few minutes with no tempo or click set, and a few seconds after stopping, it would generate a tempo track, line your music up, and maybe do a little quantizing. It worked out a reasonable tempo and time signature, and I think it guessed a key. The result was almost always immediately usable with no tweaking.