Change speed of entire file using a small part

I've got a unique issue I hope someone can help with. Using LPX 10.0.7.

 

I am restoring a bunch of cassette dubs of a friend's college radio show. The cassettes were recorded on decks that weren't maintained very well, and the drive motor speed is a little different over the span of time that the tapes were recorded (there are no wow/flutter issues, all of them are just recorded at slightly the wrong speed). I have one file for each show, regardless of length (the shows are typically between 60 minutes and 3 hours in length).

 

The shows have music played from CD, so if I have a copy of a song that was played on CD, I have a reference for speed, and also for Match EQ (which is a great trick to restore attenuated frequencies). What I wish to do is use a rip of the reference song on CD to match the speed. So I put the ripped song in a second lane next to where it appears on the show. I would like to use FlexTime on the Speed algorithm to adjust the length (therefore changing the pitch and speed) of the show recording to match the reference song, which is close enough to "restore" these recordings as my friend wishes.

 

Here's what I can't figure out. I did it a few times but I can't remember anything I've done differently compared to what I'm doing now. I want to trim the show recording down to just the reference song, and resize the show recording region by Option-clicking and dragging the edges so that the two waveforms line up properly, then drag out both sides of the show recording region to bring the rest of the show back onto the timeline.

 

I did this a few times months ago when I was starting to play with these files, and I thought it worked. After awhile, if I'd switch into Flex View, I notice that there are Flex markers at the places I originally Option-dragged the edges, and the rest of the file is not retimed.

 

When a file is three hours long and you're trying to match a three-minute segment to a reference, it's an endless, maddening loop of zooming out to find the end of the file, Option-dragging the region in or out just a little, zooming back into the song area, moving the reference song to match (because the point in time where the song occurs in the show has moved), noting that it needs to be further adjusted, zooming back out to find the end of the file, and so on.

 

I guess I just wasn't noticing that I was only time-correcting the one song when I started out, but I totally thought this worked back then, maybe it never did. Is there any way at all to adjust a small portion of a larger file to the correct speed and apply that rate of correction to the rest of the region?

 

FYI: I can't break the shows into smaller files, because the same issue applies - when one segment is properly timed, how do I tell exactly how much it's been corrected and apply the same correction? I also can't use Varispeed because I understand the algorithm isn't as good as FlexTime, plus the reference file would also be sped up with Varispeed as it affects all lanes at once. I am doing this in Logic because I am also doing other types of restoration - noise reduction, compression, EQ matching, etc., that I prefer to do non-destructively and have the horsepower to do in realtime.

 

This is driving me nuts. I hope someone can help.

Does Varispeed also affect SMPTE locked region (reference CD audio) ?

I don't know, but I was hoping for a way to do it visually. I'm assuming there's no way to re-time a portion of a file and then pull the sides out to put more of the file in the lane and have the time correction apply to all of it?

In other words: have you tried using Varispeed after SMPTE locking the reference CD audio region ?

I haven't but I will and report back. Is there any truth to the rumor that Varispeed is lower quality than Flex?

Both Varispeed and Flex are lower quality (they use same algorhythms afaik) compared to i.e. iZotope Radius or stretching in RX.

 

you can create a short reference, calculate the difference in length in %, and then go to isotope RX and stretch for the said %.

If "money is no object", Celemony offers very high quality (professional) results in that domain.

I can confirm that "Locking SMTPE position" of the reference track does not prevent it from being affected by Varispeed.

 

I was hoping not to have to use an external program to re-time it, even though with a little math it's possible, as I was hoping to have to store only one copy of the original file, not the original and a retimed one in addition to the final render.

 

I'll monitor this thread for any other ideas, but it looks like I have to retime in a separate app. I wish Logic had the "warp from here at x%" functionality that Ableton Live has, where you set up a couple of bars to be a specific tempo and it changes the rest of the file to match.

 

Thanks.

I can also confirm from looking at iZotope RX documentation that RX/Radius will not do syncrhonous resampling, just changing the speed while keeping the pitch normal. I have an older app that uses DIRAC for this sort of work, and you can make it just speed up or slow down the audio, taking pitch with it, so I guess I'll have to use that.

 

I assume the Celemony product you're speaking of is the $49,000 Capstan, which is made for wow and flutter repair, not constant slow/fast tape drive speed. And I don't think I could use Varispeed in Logic anyway, because it's only got two decimal places of precision, and on the first recording I'm looking at, it appears to be 2.118711291911% slower than the reference audio.

 

I know Logic isn't designed for this, but for Pete's sake it could be, and I don't know where people get off thinking I can buy a new $200-500 app for every different audio project I need to do. Apparently not even the $1,200 RX3 Advanced can do this simple thing.