Question regarding speed/pitch correction

[Gordy]

I am a newbie to the world of speed correction, and since there are plenty of great shows out there that simply didn't run correctly, I took it upon myself to try and fix them for public consumption. I used Goldwave recently to slow down a short Mogwai show from 1997, for example, that ran too fast.

I slowed it down to 98.5% (-2.5) on the scale until the pitch of the song, "New Paths to Helicon 1," matched that of the original recording and live shows. I've been told I have perfect pitch; the only problem is my understanding of musical theory is a bit shoddy. I can tell you if a note matches or if it's off, but I couldn't tell you if it's in A sharp or B flat or whatever.

Basically, my first main question is this: once I've corrected the pitch, am I done? Does correcting the pitch automatically adjust the speed to its intended setting; i.e., the way it was played live?

Thanks for taking the time to read this.

[Audioarchivist]

Originally Posted by Gordy

I am a newbie to the world of speed correction, and since there are plenty of great shows out there that simply didn't run correctly, I took it upon myself to try and fix them for public consumption. I used Goldwave recently to slow down a short Mogwai show from 1997, for example, that ran too fast.

I slowed it down to 98.5% (-2.5) on the scale until the pitch of the song, "New Paths to Helicon 1," matched that of the original recording and live shows. I've been told I have perfect pitch; the only problem is my understanding of musical theory is a bit shoddy. I can tell you if a note matches or if it's off, but I couldn't tell you if it's in A sharp or B flat or whatever.

Basically, my first main question is this: once I've corrected the pitch, am I done? Does correcting the pitch automatically adjust the speed to its intended setting; i.e., the way it was played live?

Thanks for taking the time to read this.

These days of digital manipulation of music can get quite confusing...

The answer is : it depends....

Are the files longer, timewise? Then you're done, with speed slower and pitch lower together. There should be a checkbox to change pitch without affecting speed, or vice-versa. You don't want to do that. Changing pitch without speed correction in tandem will stretch the recording, or changing time without simultaneous pitch changes will be wrong, too.

Look at length of file before and after. They should be the 2.5% longer (or was that shorter) ie a 1 hour show should be an hour and a couple minutes now.
One other word of advice for you is to JOIN all the files of the show into one, and apply the speed correction to the entire show, then re-track split. If you don't you'll introduce sector boundary errors on almost every track. Real time lengths and CD frame lengths won't match when you lengthen individual tracks, and new tracks will cut off milliseconds/ add blank bits, creating poppong/clicks/silences between tracks.
Hope that helps...

[Gordy]

First of all, thanks for the detailed response.

What I did, for example, was approach a flac fileset for Peter Gabriel's "Before the Flood" demos. They all ran a bit fast, and I found that when I applied the slowdown to "Here Comes the Flood" and "Excuse Me" (the only tracks I could reference elsewhere, since the others never showed up on any other releases), they match the officially released version: to quote 65daysofstatic, "one time for all time," in a sense.

When I burned them to audio, I actually didn't hear any SBEs. The songs weren't too long, the average length being about 3-4 minutes or so. I just learned that, in Goldwave, there's a box that says Preserve Tempo, to which I assume you're referring. I'm happy to note that it remained unchecked during the process (thank God that's a default setting), so each file was a couple seconds longer than before.

Again, thanks for clarifying things. I believe I got them right, looking in retrospect; with help and information, I hope to be able to fix shows without making any stupid mistakes in the process.

[Audioarchivist]

I was thinking more like a live concert, where tracks run into each other unbroken, as far as doing a join of all tracks before doing the speed adjust, then to re-track...
For those demos, where they're silent between tracks, it's not as crucial to join to prevent sbe's. The quiet will hide any sbe errors.
In the case of a show recording, it will matter more.

Those gabriel demos are cool. Does yours skip a bit in "Excuse Me"? "...I'm looking for lost Aaaaan-gel-es" becomes "..I'm lo-lo-lo eees..." Damn.

Good luck with your future audio projects...

[Gordy]

Yes! It does skip. But I believe the text file pointed out that it was a result of a botched cassette to CD transfer and that it's not an error on our side. Nevertheless, I listen to these demos endlessly. "God Knows" is a gorgeous song.