Syncing MIDI to .wav?

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Post by Guest » Tue Sep 28, 2004 11:37 pm

I'm an old-school MIDI just starting to dig in to analog audio... and importing .wav files. I've tried through all the "help" functions and searching here. Please help me figure this out. It's kind of azz-backwards from how most do it. On some things, I don't want to record MIDI first to give me sync-time for my audio to be imported over. I want to import .wav files from my harddrive and get timing from those .wav files, and THEN sync MIDI up to that. I've done it in real time, but then I pay no attention to measure lines or ticks and just play midi info on my synth to the audio file already imported.... I want to be able to sync everything up so both .wav. and midi fall right on measure lines, but I want to import my .wav first.
I have Pro Audio 9.3, and I want to learn how to:
1. After I import .wav files,
2. How can I sync the tempo of the .wav file to line up with measure lines (I need to "rip" timing from the .wav file, and then slide the .wav file to match beat 1 with beat one of a measure.... most of what I'm doing is constant timing so I don't need ritards or accells)

Thanks in advance... I'm learning as I go but am sure I'm going about some things the "long way". And I can't for the life of me figure this out.


Randy G
Posts: 3
Joined: Sun Jan 08, 2006 12:13 am

Post by Randy G » Wed Jan 18, 2006 8:36 am

Man this brings memories from 1988 of trying to manually lay down a MIDI sync track from a Roland TR-707 onto a song already recorded on 24 track analog, and riding the tempo wheel to try to sync up the beats.

Allan Green
Posts: 1
Joined: Mon Mar 06, 2006 1:58 pm
Location: Birmingham, England

Post by Allan Green » Mon Mar 06, 2006 2:35 pm

Hi,

I was hoping to solve this exact same problem, so I just joined this forum...and found that someone else had already asked! I often want to transcribe my fave guitar stuff, and now use Sonar 5PE to do so. (Quite honestly the jump from my previous version Sonar 2 (?) doesn't seem to have made life easier but then maybe I haven't read enough of the manual yet.)

Here's the way (probably rather horrid) I currently tackle this problem...I'll assume here that we'll be using 4:4 timing - not difficult to recalculate though i guess.

First step is to move your wave file away from the 0:00 postion by half a second. This lets you have a few bytes worth of midi data which might be needed to initialise your midi gear. (I'm not certain exactly how important this is... I've never actually done anything with it yet but it doesn't hurt and I'd rather do it before actually adding any notes!)

Create a midi track. Set the tempo initially to be 120bpm and you'll find that the first "dummy" bar ends exactly at the start of your wave file. If the audio begins after the start of the wave file (very likely) you can afford to raise the tempo of this bar accordingly.

Now, set the cursor to the point in the audio where the audio begins (turn off snap to grid or it just won't go there!) Play the tune while watching the audio waveform graph to spot the point in the tune where the second bar begins. Halt the play. Now here the fun starts... insert a new tempo at the cursor position (i.e. beginning of midi bar 2/audio bar 1) and adjust the tempo value using up and down arrows until the peaks align with the bar lines drawn across the audio waveforms by Sonar. This can be fiddly, but I usually don't bother to go for greater accuracy than 1bpm. Unless you listen to music produced against a click track then the tempo will change anyway. For most rock you'll be starting off at about 90bpm but I guess this varies hugely in other genres! (I should also add that not all music starts on the first beat of the first bar. I could try to explain this but it would take me about a million years.)

Ok, now play again, and after a few bars you'll notice that the midi and wav begin to slip away from synchronisation. Reposition the cursor, and again insert a new tempo. (If you try to adjust the existing one you'll just screw up the work you've already done.) And so it goes on, repeating every five bars or so.

Although this method is not utterly accurate (unless you bother to reset the tempo every bar!) it seems close enough to me. Although not exactly an automated feature, you can set up the tempo map for a typical 3 or 4 minute song in about 10 minutes, which is generally a very small proportion of your total project budget!

I do worry about the fact that the tempo changes in a discrete step-wise fashion rather than smoothly. However, I cannot honestly hear it in the stuff I listen to. Most of the adjustments are in the 1-2 bpm range so the errors are actually quite small in ms per beat reckoning. Probably much smaller than my keyboard playing timing errors anyway.

There may be much better ways than this! If so, do please post them!

What we really need is a feature which justs lets you "put barline here" against the wave file graph. But I don't know whether there would be enough demand for it...

Regards,

Allan.

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