Using real Time stretching and pitch shifting

dubcotics · Post by **dubcotics** » Wed Oct 01, 2003 2:49 pm

Hi there,
I've been using real time stretching and pitch shifing for a month, I've had fun with it, but I was rather disappointed by the fact that TS and PS are performed using the host cpu instead of the dsp. I'm using a p3 500 mgz, I know it's a jurassic one I mean in technological terms but works fine for me. I would like to know if those of you with fast computers experience a strange and dreadful metalic sound when reducing the tempo of a sample. I was ordered by a friend who deals with dubbing movies to match the tempo of a sound track to one of a speech, the result was terrible as the experience resulted in a metalic sound like when you add some effect flanger or phaser , don't know if the effectiveness of TS and PS depends on the cpu capabilities, I really bought the sample for that purpose, so if any sts guru can explain this I'd be very grateful...

kensuguro · Post by **kensuguro** » Wed Oct 01, 2003 8:26 pm

I'm no guru, but STS5000 uses stft or some sort of fft algo to do the timestretching and pitch shifts. The trade off is exactly what you are getting. Depends how must of a stretch you're doing, but you'll get that bubbly sound on transients. FFT is a balance between pitch domain accuracy and time domain accuracy(transients). The more pitch accuracy you assign, the more transient you loose, and vice versa. In STS5000, you have presets, like "voice" or "instrument" or whatever. Try doing the analysis with different presets and see if you can get better results. Either way, I don't think it was meant for shifting an entire mix. And entire mix is very hard to because it has a wide spectral content, and also a wide range of dynamics. Also, make sure you have the correct analysis for the file you're using right now. STS5000 will give you VERY strange results if you run a sample through an analysis of an older sample. (sounds like a brokenr radio)

If you want a near flawless pitch shift or time stretch, try cool edit's. It's a very slow algo, but works well on a final mix. Also, native instruments has a new plugin out that uses a strange mix of fft and wav slicing. It differenciates between the attack and the body (sustain, decay) of the sound, and does different fft runs on each of them. So it uses fft, but overcomes the time domain accuracy defficiancy by doing several different runs. Pretty smart approach if you ask me.

[ This Message was edited by: kensuguro on 2003-10-01 21:30 ]

samplaire · Post by **samplaire** » Thu Oct 02, 2003 3:33 am

Try ProTools free found on http://www.digidesign.com. It features a good timestretching. And it's free

In my case I was dissappointed with the PT timestretching because it didn't do the flange effect and I wanted it

_________________
Sir Sam Plaire Scopernicus

[ This Message was edited by: samplaire on 2003-10-02 04:34 ]

braincell · Post by **braincell** » Thu Oct 02, 2003 10:49 am

On 2003-10-01 21:26, kensuguro wrote:
I'm no guru, but STS5000 uses stft or some sort of fft algo to do the timestretching and pitch shifts. [ This Message was edited by: kensuguro on 2003-10-01 21:30 ]

Not a guru? but you are a guro!

kensuguro · Post by **kensuguro** » Thu Oct 02, 2003 11:35 am

good one! LOL
2 points for braincell

[ This Message was edited by: kensuguro on 2003-10-02 12:36 ]

dubcotics · Post by **dubcotics** » Thu Oct 02, 2003 6:48 pm

Well it's a shame to have spent so much money cause I could've spent that money on something else, and it makes one frustrated to know that they are free softwares available on the net that do exactly the same
or at least to mimic TS and Ps..

kensuguro · Post by **kensuguro** » Thu Oct 02, 2003 10:36 pm

dubcotics.. well, you really haven't spent it on a bad deal tho. I mean, sts5000's TS and PS is meant specifically for monophonic samples. It works great when used correctly. (especially with vocals) Anyhow, don't feel down about it. I'm sure sts5000 with become useful in its own right sooner or later.

braincell · Post by **braincell** » Fri Oct 03, 2003 1:54 pm

The Free ProTools will not work under Windows XP.

On 2003-10-02 04:33, samplaire wrote:
Try ProTools free found on http://www.digidesign.com. It features a good timestretching. And it's free In my case I was dissappointed with the PT timestretching because it didn't do the flange effect and I wanted it

_________________
Sir Sam Plaire Scopernicus

[ This Message was edited by: samplaire on 2003-10-02 04:34 ]