Tempo map

[norfolkmastering]

2 hours ago, David Baay said:

That's exactly what Set Measure/Beat At Now (Shift+M) does as mentioned in the last post. And you can Tab to transients to assist in locating the Set points. You can set as many or as few points as needed to align the timeline to the performance with tempo changes calculated automatically by Sonar.

That is great news!

How does Sonar know how many beats to put between the points I add?  Let’s say I add a point then another point 5 beats later, then another point 7 beats later, basically wherever I see a clear beat in the audio waveform.

Thats the bit I don’t understand.

[David Baay]

34 minutes ago, norfolkmastering said:

How does Sonar know how many beats to put between the points I add?

You specify the measure and beat (or fraction of a beat where needed) that you want to correspond to a certain absolute Now time in the audio, and Sonar calculates the number of beats since the last set point (or 1:01:000 if nothing has been set yet) divided by the absolute fraction of a minute to that point in the audio, and that gives bpm for that interval. It shifts the timeline accordingly around both audio and MIDI without changing the absolute playback timing of either.  It's magic.  ;^)

If you find later that the tempo for a four-bar (for example) segment that you set is letting the audio drift away from the timeline in between, you can set intermediate points as needed to dial it in; you don't have to do everything in order from start to finish. One caveat: Never delete a tempo change that SM/BAN has made; always Undo back to the point just before you picked the wrong beat or transient to set, and re-do it. Actually this isn't so critical for pure audio projects but is for MIDI or projects with clips that don't all start at 1:01:000.

Edited 18 hours ago by David Baay

[norfolkmastering]

I will give it a try tomorrow.  Thanks so much for the explanations.

[msmcleod]

14 hours ago, norfolkmastering said:

That is great news!

How does Sonar know how many beats to put between the points I add?  Let’s say I add a point then another point 5 beats later, then another point 7 beats later, basically wherever I see a clear beat in the audio waveform.

Thats the bit I don’t understand.

The way Set-Beat-At-Now (SBAN) works, is you set the now time at, say, measure 2 then tell Sonar that is measure 2.  It takes the time in seconds/fractions of a second, and works out what tempo the song needs to be prior to that point (but only from the previous tempo change if there is one) to make measure 2 land at exactly that point in time.  As you keep doing that throughout the song, the tempo map is built up.   

You can do this at whatever granularity you need - either by beat, measure or even every "n" measures.  If the tempo of the audio is fairly consistent, you may get away with using SBAN every 4 bars or so;  if it's varying wildly, you may need to do it every bar or even every beat.

In saying that, even if the tempo on the performance does vary wildly, if you only ever need the bars lining up rather than each beat, you could get away with just doing it on a per bar basis - it would just mean that some 1/4 notes may not line up exactly on the timeline.

 

[msmcleod]

I think it's worth mentioning that unless you're adding MIDI parts or need a Sonar-generated click-track, it's not always necessary to have a tempo map.  Even if you're adding MIDI parts, it doesn't really matter unless you need to edit them.

You can have tempo set at 120bpm for the whole song, and the audio going between 85bpm and 90bpm, and it won't make a blind bit of difference. The only thing is that the time-ruler in M:B:T won't match the material.

If I've got a live band recording with only audio tracks, for the most part I don't care about beats/measures.  I'll just set the time ruler to H:M:S:F and mark out verses/choruses with arranger sections (with the arranger track in absolute time).  That way I can easily navigate throughout the song and never need to worry about bars & beats.

Where it does get useful is if you want to vary / correct timing.  But there's nothing stopping you doing the tempo map later only if you actually need it.

What I would recommend though, is if you are correcting timing by nudging the odd snare beat around, do all of your timing tweaks before you define the tempo map.

[norfolkmastering]

I had a first try this morning and it seems to work really well.  It's smart enough to know which measure I've clicked close to, even if that measure is not exactly aligned to the beat in the audio waveform.  My method at the moment is to keep an eye visually where the measure (n the timeline) starts to wander away from the visual beat on the audio waveform, then pop a 'Set-Beat-At-Now' there.  It will take a while to do the whole song but it's very stress free!

I worked out what the initial tempo was and put a bar of silence in before the start of the audio.

I need a tempo map for this particular song as we're doing a cover of a classic 70's song and want to match the original tempo.  This makes it easy to programme a temporary drum track (and of course a click track) for the band to build up the parts from and also makes referencing to the original track easy as it sits in its own track on Sonar.

[norfolkmastering]

I had a little challenge when there was a slower bridge in the middle of the song which I didn't do a very good job at the first attempt.  By that time I had done the rest of the song!  Ooops!

So I had my first experience of having to edit tempo points in situ!

I put SMPTE locked time markers at a few point along the slower bridge audio to mark where I was sure there should be tempo points and then played around with the tempos between these points until it was sorted, taking care to ensure that the tempo points I added/edited time ended up aligned with the audio markers.  Not too difficult after some practice and it worked a treat.

'Set-Beat-At-Now' is a GREAT TOOL!!