? Changing Pitch But Not Tempo

[lrossmusic]

(Topic should have read (?Changing Tempo But Not Pitch)Sorry.

 

One of the features of my Cool Edit 2000 program allows me to change the tempo of a recording without changing the pitch. However when I tried this once or twice I was not satisfied with the sound quality of the conversion. I am thinking there must be more professional programs that can accomplish this without sacrificing the original sound quality. Anyone ever done this type of editing before?

 

Anyway specifically this is what I am trying to accomplish.

 

I have a 2" master with a simple backgound vocal part on a few tracks. The tracks are of a group of kids echoing the lead vocal in a call and response type exchange. For example the lead vocal part will be-

 

"say I wish".....and the kids reply .."I wish"

 

What I want to possibly do is use the original kid's background part with a new and slower re-recording on a new master. Since the new track will be slower I want to be able to match the rhythm of the kid's response with the new and slower lead vocal without lowering the pitch of the kid's voices.

 

I figure that I will need to somehow sample the kids part from the original 2" and then punch them in at the desired places on the new master after having slowed the tempo slightly.

 

I don't have much experiece working with samplers or tempo changes but from what I have been reading this type of thing can be done without compromising the sound quality.

 

Am I correct or will this end up being so technically complex and time consuming that I would be better off just re-recording the kids from scratch?

 

Thanks in advance for any suggestions or comments.

[Angelo Clematide]

yes, i do that often, the software i use for that is

 

a) Logic: Time and Pitch Machine

b) Ableton Live4

c) Melodyne

d) Cubase SX, Audio Warp: Realtime Time Stretching and Pitch Shifting

 

for what you descibe, the Audio Warp is a fast way to do it, it happens in realtime.

 

The resulting quality depends on how far you wanna transpose, and how good the original data is...

 

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[Billster]

MOTU Digital Performer offers this function as part of their "Pure DSP" features.

 

I've been experimenting with making "bass" out of guitar, dropping single note lines a whole octave. They sound a little weird, but mostly lack true bass guitar depth, the timbre is not too bad, just thin. But for that particular deal I was going for an unusual sound.

 

I don't know what it would sound like on more harmonically complex material, like the group of voices you describe.

 

I have a lot of confidence in the MOTU stuff - if you are tuning a few half-steps at most, the quality should be acceptable on a blended sound. I don't know if I would use any sort of tuning algorithm on a prominent lead part

[Angelo Clematide]

for vocals, so circa min./max. changes without recognizable reduction are:

 

+ speed change (faster): 20% (i.e. 100 Bpm to 120 Bpm)

 

- speed change (slower): 15%

 

transposition: up/down two halfsteps

 

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[C.Jader]

I've had good luck using Sonar 4's MPEX time compression and expansion for vocals, you need to go in and select the algorithm for Vocals to get the best result.

[lrossmusic]

Thanks gentlemen!

 

So I guess I just need to find the right studio that has some of the programs you mentioned and an engineer familiar with the process.

 

Since my original material is on 2" and recorded at 30 IPS the source material is pretty high quality. Therefore from what you are saying to slow the tempo slightly will not take away from the fidelity too much.

[BOOKUMDANO]

Sound Forge and Wavelab can easily do that type of stuff. Once you know what you're doing, it probably only takes ten minutes or so to get the old vocals copied to the computer, adjusted the way you want for pitch or time and then dumped back to the new slower tape track.

[fantasticsound]

I see a lot of information on this thread, but the bottom line for me has always been that time expansion of a track always introduces artifacts. I have yet to hear a good expansion beyond 2% - 4%. Before you spend a bunch of money on an editor, maybe you should look into the cost of re-recording the kids. If you still have to record the other new tracks, this should cost a pittance unless the kids themselves are to be paid a sizable amount.

 

Anyone care to share a multi-voice, expanded track soundbite and the original it was derived from?

[boosh]

I will do it for ya if you like.....

As long as the change in tempo is not drastic my Wavelab will do a perfect job.,...just PM me if you'd like to try it.

Boosh

[lrossmusic]

Originally posted by fantasticsound:

... Before you spend a bunch of money on an editor, maybe you should look into the cost of re-recording the kids. If you still have to record the other new tracks, this should cost a pittance unless the kids themselves are to be paid a sizable amount.

 

Neil I wasn't going to try to do this myself or buy any program or sampler or anything. What I was thinking is that I could waltz into a studio with my 2" tape once we finished the new slower track and somehow get the parts on the new tape. I was hoping to find a studio that already had some of the stuff mentioned above and an engineer who knew how to work it.

 

I don't expect the tempo to be that much slower (another artist is going to do the tune)and the part itself is not really sung so it might actually work without much tempo adjustment at all. The original tape has 14 kids repeating a spoken word call and response type segment. You can hear what I am talking about at the following link - (click on sound and then track #16)

http://www.lincolnross.com/main.html

 

 

OTOH you might be right. It may be easier to just take a new bunch of kids back to the studio.(The original tracks were done some time ago and those kids have grown up). The cost wasn't so much what I was trying to avoid just the hassle of getting a bunch of knuckle heads to and from a session.

[Angelo Clematide]

Originally posted by fantasticsound:

... but the bottom line for me has always been that time expansion of a track always introduces artifacts. I have yet to hear a good expansion beyond 2% - 4%.

in the true sense of the word "artefact" (a object produced or shaped by human craft), you are right, it is a modification. For a high-class acoustic product, i wouldn't change speed nor pitch, it would sound unnatural for very sensitive listeners...

[Angelo Clematide]

Originally posted by lrossmusic:

The original tape has 14 kids repeating a spoken word call and response type segment.

this may work without tempo change at all...

 

Have the sentences cut into smaller phrases or single words, and move the beginning of the words/phrases to the rhytmic correct start.

 

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