Wednesday, July 1, 2009

Changing Your Sex The Easy Way

As I've mentioned a time or two recently, I'm in the final stretch of production for my next album. Today I was working on one of the final vocal tracks and was getting frustrated. The verses sounded fine, but the vocals on the chorus didn't punch through and 'lift' the way I generally like them to. One of the techniques I use a lot on choruses is to add another layer of vocals sung an octave above the main one. It adds some energy to the track and brings the chorus up a notch nicely. But with this song, the main vocal was already somewhat high, and an octave up was simply out of my vocal range. For the hell of it, I tried using a pitch shifter on a second layer of vocals, but, predictably, this lead to the dreaded "munchinization" effect and it sounded like I was singing a duet with the Chipmunks.

The reason this happens when you use a pitch shifter is because it not only shifts the pitch of the vocal, but also the formant and this doesn't happen in nature. Formants are a function of acoustic resonance. In layman's terms, part of what makes your voice sound the way it does is because your body and throat resonate with the frequencies of your voice, much in the way the body of an acoustic guitar does with the vibration of the string. So whether you sing a low note or a high note, the size of your body and throat remain the same and thus, the formant remains constant. Pitch shifting shifts the formant as well, so as you go higher, it sounds as if the voice is coming from a smaller body, and as it goes lower, it sounds like it's coming from a bigger one. (This is all gross over-simplification, but I'm trying not to put you to sleep...)

Enter Logic's Vocal Transformer effect which allows you to change pitch and formants independently. I pitched the vocals up an octave, which resulted in the expected helium-type effect, but when I also nudged up the formant (I used a value of +4), my vocal track suddenly bore a striking resemblance to a natural female voice singing the part. If I were female (apologies to anyone who just got that image in their head), I might pitch my vocal down an octave and nudge the formant downwards. As it exists now, the Vocal Transformer is not without some pretty significant artifacts that mean you can't use it on an isolated track without being obvious (although some might dig the unnatural timbre), but used as a harmony part, it came out pretty damn convincing. Convincing enough that I sent the track to my bandmates and they couldn't guess the source of the foxy female backing vocals.
(For you non-Logic users, there are undoubtedly other effects out there that do the same thing...)

So if you'd like to hear what you'd sound like as a member of the opposite sex, remember that shifting pitch and formants
both are necessary for convincing results. And that's a lot cheaper than a trip to Thailand.

(The album doesn't come out until October, so I'm not going to post a sample here, but for those curious enough to wait a few months to hear it, just look for the track called "Angels & Demons".)

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