Speed and pitch correction

Discussion in 'Audio Hardware' started by Patrick M, Mar 18, 2002.

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  1. Patrick M

    Patrick M Subgenius Thread Starter

    Location:
    US
    I'm curious -- to those of you who play around with speed and pitch correction in digital audio software, how do you figure out what to do to make things right? Meaning, is there a "scientific" way to get pitch and speed correct on, e.g., a live recording? I don't have perfect pitch, so I'm pretty sure I couldn't fix everything "by ear."

    I have a live show from webcast I'm playing with, and it sounds slow and flat to me. I'd like to "prove" this, but I don't know how to do so, or what to use for reference. Any ideas?
     
  2. Sckott

    Sckott Hand Tighten Only.

    Location:
    South Plymouth, Ma
    Someone came to me to have a bunch of commercials on reel transferred to CDR. I noticed one of them, recorded 3% slow, needed some help, but what helped was, they used Dave Brubeck's "Take Five" for background. So, I used Cool Edit for Transform/Time-Pitch/Stretch. Since I've heard "Take Five" about a gazillion times, yes, the commercial sounded normal finally, and less like the script readers were still in puberty (although I think they might 'ave been).

    When the Bob Dylan "Royal Albert Hall" Columbia bootleg came out, the 3 track tapes weren't in perfect pitch, but Bob's harp always was. They used that to get the speed correction right.

    What you might want to do, is play with that until you can get the sound that sounds normal. Use a vocalists key or maybe the bass guitar. Not everything had to be in tune that night, but most musicians strive for psydo-perfection. A couple of things a little out of whack and the vocals will sound horrible. The creative balance of teamwork crumbles.

    You can test the track before you finalize it. If doubtful, keep your original copy from the evil trading circle. Ya never know when you might need it. (Mark: Master-do not use)
     
  3. Grant

    Grant Life is a rock, but the radio rolled me!

    Patrick, i'd love to help ya, but, while I can also tell when something's off, I can't identify a middle C that well.

    When presented with cases like this, I use my best judgement. I try to use vocal cues to get in the ballpark. One of the problems are that you can't be certain that the instruments are tuned to western pitch or if the misic is played that way.

    Say I had to pitch correct a live Rush concert. There would be no way of knowing how to get Geddy Lee's vocal right without a reference because I am not too familliar with their music.

    Try finding a recording of the band, if they have vocals, and go from there.
     
  4. Paul L.

    Paul L. New Member

    Location:
    Earth
    Patrick,

    If you need something "scientific," you could use an electronic tuner in front of the speaker. But you'd have to have one instrument steady on a note for a while for that to work.

    You don't need perfect pitch at all. Perfect pitch is when you can identify a note is an "A" for instance, and that it is slightly flat, for instance, without comparing it to anything else for a reference. The reference is solely in the brain for someone with perfect pitch. Studies indicate people with perfect pitch lock onto it while babies, and that there are different ranges that constitute perfect for different people. In other words, one guy might feel anything +/- 0.1% is perfect, and someone else might think something +/- 0.3% is perfect. A lot of time perfect pitch people are very disturbed listening to music that is off pitch.

    Better actually is to have excellent relative pitch. That's where if you have something to compare it to, you can tell whether yours is flat or sharp, and how much to adjust.

    Something like a song flute is good to use. If you compare to a piano or a guitar, you have to make sure it is tuned right first.

    As the other guys said, this can all be problematic, especially with bands at live shows. Sometimes one musician can be out of tune with another, or they can all be out of tune compared to a perfect reference. Or a guitar can go out of tune before a guitar tech fixes it. Or dozens of other things.

    If you make a 6% change in a sound editing program, you're changing something a semitone, which is huge. But lots of times one official release will be off compared to another official release by 1%, for example. And while just about anyone could tell if you switched from one of these official releases to the other, most people don't notice it just hearing one by itself.

    Someone that's good has to really strain to get it very close, like 0.1%. Look at it like you're breaking that semitone span down into sixty increments. Some people are going to say anything that falls into that span is okay. But most people when you get closer to one end or the other are going to notice that it's pushing it, that a note's getting flat or sharp. Fine tuning to the 0.2% or 0.3% is quite realistic for somebody really good though.

    Let's take a 4 minute song. That's 240 seconds. 1% change is 2.4 seconds, either shorter or longer. But a 0.1% change is going to be just a quarter of a second shorter or longer. That's the time it takes to sing maybe a word or a syllable.

    To get back to your original question (!), if in doubt, find a musician friend who can tell what key the band is playing in, and have the musician listen to a short segment of the show in your editing program while playing along on an instrument that's in tune, and make the necessary adjustments.

    Also, always use the best quality setting (which takes the longest to process). The lesser quality settings can supposedly give you ringing and other bad things.
     
  5. Patrick M

    Patrick M Subgenius Thread Starter

    Location:
    US
    Thanks for the responses so far.

    Now, anyone up for some hands-on fun? :p

    I took the live version of "What is This" and collapsed it to mono, then isolated the first chorus. I did the same thing for the original studio version, then put the live version in the right channel and the studio version in the left channel. It's available as a 3.8 MB download.

    You won't need a boatload of bandwidth, so if anyone wants to check that out and let me know what you think, please do!
     
  6. Holy Zoo

    Holy Zoo Gort (Retired) :-)

    Location:
    Santa Cruz
    I just listened to the clip - and yeah, it sounds like it's running slow (or the recorder was running fast... who knows).

    One way to check is whip out the guitar and learn the lick at the right speed, then see how far low it is on the live version. That'll tell you how far off it is.

    Or, just wing it... raise it a couple percent until it sounds right. :)

    I'll give it a try and see what I come up with.
     
  7. Holy Zoo

    Holy Zoo Gort (Retired) :-)

    Location:
    Santa Cruz
    Here's what my brother (a producer/recording engineer who has an amazing ear) has to say:

    "200 cents higher would make it in key with the studio recording.

    His voice sounds pretty strange in either case though. The clip is short so
    maybe it's just this small section where he sounds this way."
     
  8. Grant

    Grant Life is a rock, but the radio rolled me!

    I tried downloading it on my wife's Compaq but had trouble. It defaults to the stupid Windows media Player and takes forever to download. Was it in WMA format or mp3? I would have used my main music production PC but I had it busy running scripts.
     
  9. Paul L.

    Paul L. New Member

    Location:
    Earth
    Speaking of cents, I should have emphasized in my post above that I was talking %, which is totally different than cents as used on editing programs.

    Cents has to do with semitones. There are about 100 cents in a semitone. To change something a semitone, you change it about 6% or 100 cents. If you're changing something 1%, you're changing something about 16.7 cents.

    So if your tape is indeed off 200 cents, that means it would be off two semi-tones (one full-tone), which would be an awful lot.

    I wasn't able to listen to your sample because my computer froze up when I tried. But keep in mind they might not be playing it in the same key live as they did in the studio.
     
  10. Patrick M

    Patrick M Subgenius Thread Starter

    Location:
    US
    That's a .wav file. You should be able to right-click on it and save it without going through Media Player or whatever.

    Zoo man --> yeeeeouch! 1 full tone off??? Would a 160 kbps mp3 of this track help?

    Thanks all!
     
  11. ferric

    ferric Iron Dino In Memoriam

    Location:
    NC
    that is one wierd sound clip. It drags, plus there is a bizarre lag between the left and right channel; like it's out of sync. of course this is low grade computer sound at my house.

    FM
     
  12. Holy Zoo

    Holy Zoo Gort (Retired) :-)

    Location:
    Santa Cruz
    As Patrick said, that was intentional: one track is the studio cut, the other is the live (messed up) version of the same song.

    What we're trying to figure out is if:

    1) the singer was having a bad night, and the band played slow to boot

    or

    2) somehow the song was recorded too slow (*)

    Patrick, does that sum things up? :)


    (*) actually, the song would be recorded with the tape player running fast, and then the playback machine - when run at the proper speed - makes things sound slow.
     
  13. Patrick M

    Patrick M Subgenius Thread Starter

    Location:
    US
    It should be a weird sound clip. One channel is the original studio version, collapsed to mono, and one is the live version, also collapsed to mono, that I'm trying to "fix." They should start very close to the same point, but one is going to lag. I included the original version so interested parties could see how the live version compared.

    It gets worse -- I'm pretty sure the live version actually changes speed within the song (and the whole show, for that matter). There are also weird phasing problems, but I'm now wondering if they are partially side-effects of the speed problems.
     
  14. Patrick M

    Patrick M Subgenius Thread Starter

    Location:
    US
    Pretty much. The other big issue is the phasing problems, but I'm not sure how much can be done to fix them. :eek:
     
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