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Tweaking the Tempo (Pitch control)

Posted: Wed Mar 31, 2004 10:45 pm
by Zot
I recently did some investigation into tools for the Mac that can be used to alter song tempos. It's fairly common to find a function called 'pitch control' on many standard DJ consoles, and I know many teachers add a pitch controller to their portable stereos for teaching purposes.

If you're unfamiliar, the idea is that the tempo can be changed (usually with a dial or knob) while the pitch is maintained. Within a certain range (maybe +/- 10%) the result can be a fairly normal sounding song with a varying tempo.

So anyway, I just wanted to find out what people generally use for pitch control in dawning era of digital DJing. I realise it's not a common (nor particularly desirable) feature of a swing DJ's arsenal, but there are undoubtedly times when it's needed... particularly for use in choreographed routines, for training, or for teaching.

The tool I eventually shelled out for is called the "Amazing Slow Downer" (MacOSX). It's pretty slick, and does an excellent job of pitch control on the fly as well as allowing you to save files at altered tempos for playback or CD burning.

Posted: Wed Mar 31, 2004 10:49 pm
by yedancer
I've noticed that changing the song with such a feature immediately catches the attention of most musicians.

Posted: Thu Apr 01, 2004 12:51 am
by Bob the Builder
As a DJ I never use pitch control in regard ton vocal songs. It just sounds terrible.
On instrumentals is kind of works. I you go to -8% it will change the key the song is in, and the song lalso ooses all its energy.
I prefer not to go beyond 4% each side. I have very rarely used it.
My pet hate is when DJ's use it mid song.

Brian

Posted: Thu Apr 01, 2004 11:27 am
by ScottieK
My venue's system is rocks. The system has an option called "Master Tempo" (or something) and it will allow the songs tempo to be changed with out effecting the vocals. I've used it up to 16% (it's max) in both directions simply to test it out.

As far as regular use, eh. I use it on occasion.

Posted: Thu Apr 01, 2004 2:56 pm
by Mr Awesomer
I'm against altering the artists original intent for a recorded piece.

Posted: Thu Apr 01, 2004 3:24 pm
by kitkat
They can do that? I went to a senior computer science presentation last year showing software he'd developed, so I knew the technology was good enough that someone with an expensive program could write a plugin for it with just a B.A. He was even able to play with it as it streamed. However, I didn't know they'd merged it with things besides computers enough that you could do streaming fourier analysis and pitch-preserving alterations with an affordable sound system...

SWEET!

Heh...if I had one on me whenever I wanted, I'd use it for teaching beginners so people could start to feel a song, and then work on increasing tempo using a recording they're used to. I can't imagine spinning swing with it, though--you stop between songs, anyway.

Posted: Thu Apr 01, 2004 4:13 pm
by KevinSchaper
Without actually understanding all the technology underneath, I think there's still an issue of processing power.. my turntable does pitch-corrected tempo changing up to 50%, but it starts sounding like a 50's robot if you low it down too far.. (or maybe that's inevitable)

I wouldn't use it for anything besides goofin off tho...

Posted: Thu Apr 01, 2004 5:25 pm
by Lawrence
Bob the Builder wrote:As a DJ I never use pitch control in regard ton vocal songs. It just sounds terrible.
On instrumentals is kind of works. I you go to -8% it will change the key the song is in, and the song lalso ooses all its energy.
I prefer not to go beyond 4% each side. I have very rarely used it.
There are two types of "pitch" controls: one that somehow electronically maintains the same key while only changing the tempo, and another that changes the key as it changes the tempo. The "pitch" control on my system is the latter; better CD players have the kind that maintains the key while changing the tempo.

I mostly use it for teaching: to slow or speed up the song for instructional purposes.

Posted: Thu Apr 01, 2004 5:50 pm
by yedancer
I forgot to mention that I used to do this a lot, but now I never do it.

Posted: Thu Apr 01, 2004 7:03 pm
by dana
We have a little pitch control slider on the decks we DJ off; I only use it for Bei Mir Bist du Schoen, you know that part near the end where it speeds up? Well I just keep speedin' her up and speedin' her up 'til people are crashin' into each other and spinnin' around inta some kinda like black hole vortex phee-nomenon.

Yeah.

Posted: Thu Apr 01, 2004 9:34 pm
by Bob the Builder
ScottieK wrote:My venue's system is rocks. The system has an option called "Master Tempo" (or something) and it will allow the songs tempo to be changed with out effecting the vocals. I've used it up to 16% (it's max) in both directions simply to test it out.

As far as regular use, eh. I use it on occasion.
Sounds very cool.
But as you say, If I had it, I'd only use it on occasion.

Brian

Posted: Thu Apr 01, 2004 9:59 pm
by Zot
So yeah, I knew it would get some responses about not being cool to use, but really I was posting this in Tech Talk to get a technical answer to a straightforward question. Do you have software you'd like to share knowledge of to the folks here? I guess we're all able to judge for ourselves when or whether it's appropriate to use it.

As a side issue -- most recording systems, including record players, vary a fair amount as far as playback tempo goes. If you haven't ever noticed this, I'm not surprised. It's difficult to pick the difference quite often (just as it's difficult to pick the difference if you use a good pitch control system). So if you're a real purist, you might say that you really only ever want to hear real, unmediated live music.

I'm in the camp that says live music is the ultimate, but I think it's tough to say that recorded music isn't useful as well. So I'll go along with some compromises in terms of quality in order to be able to hear it when & where I want to hear it. (i.e. To my way of thinking, the facility of recorded music is a pretty moot point these days). Like I said in my original post, there are only a very few occasions when I would want to use pitch control, but they do exist. Hence the request to hear from others who've had experience with good software for doing it.

Posted: Fri Apr 02, 2004 12:05 pm
by julius
I use Pro Tools. It only costs $15,000.

(note: i'm kidding. about using pro tools i mean. not the cost.)

Posted: Fri Apr 02, 2004 3:41 pm
by Ron
Matt - I just bought Amazing Slow Downer as well, after I received some cool modified songs. I haven't tried it much. But I was very impressed with the quality of the songs she sent me. Before when I'd tried to edit songs to slow/speed up the song without changing the pitch, I noted that they sounded distorted. It seems to me that Amazing Slow Downer can change a song up to about 20% without distortion. I'm going to have to play with it some more, though, and listen very carefully.

Anyhow, this can turn 110 BPM songs that I would never play into 135 BPM songs that have a nice rhythm. I wouldn't do it to songs that are well-known at any tempo, I don't think.

I'm in the camp that thinks editing songs for dancers is OK. I don't do it often, and I always mark the song title as edited so that it's clear that I've changed the original artist's work.

Just messing with the standard tempo control on the typical DJ setup is silly. When you change the tempo you change the pitch, and when you change the pitch of a song by more than a few % and it's noticeable, and a few % doesn't make much difference, anyway.

Posted: Fri Apr 02, 2004 3:53 pm
by julius
A 10% increase in tempo without keeping pitch constant is about a half step up. So a song in the key of A would become a song in the key of B flat.

i have no real point here.