Quality of timestretch

Ok it’s definitely good to have timestretch in renoise . However i see there is something quite wrong with it . As soon as enabling it on a anything it starts to sound different even on the root note of that sample , like if you enable it on vocals they sound different , even played on the root key . It sounds much better if you leave it disabled . So what is the point ? Time stretch is usefull to change tempo without changing pitch and still have reasonable quality .but not losing it at its root note .Am i doing anything wrong here ?


Maybe you use “repitch” algorithm, if yes, try others.

No , not that one . Texture Or percussion . But as soon as being enabled the sound loses it’s character . Sometimes transients and sometimes the whole soubd loses high freq content.

Can’t use it for vocals , if you want to change tempo of the song .time stretch does something to the sound . Percussion mode is a little better sometimes but not flawless .

It’s worth mentioning that the recent time stretch us actually quite good for sound design in my perception but not good if you want the actual quality of your sample( even vocals) to be intact when using time stretch . I’m not expecting it to be great when going very much high or low in pitch or change tempo too much .

Rubberband is not the best. “zplane” is industry standard, as far as i know. Used in Bitwig and FL.

1 Like

so you mean the algorithm is not the best of timestretch in renoise ?
Ok cool anyway .

I’m getting quite lot of crackling noise when using timestretch when used on non-c notes. Non-timestretched samples play fine so I suppose this is a bug in timestretch. Both texture and percussion mode. It makes the whole feature unusable. Anyone else suffering from this?

Running on Ubuntu 19.04 / JACK with realtime threads set up.

I also realized that the sample changes even at root note when enabling timestretching. I think part of it is that both modes reduce the volume of the sample (to different degrees). I have not done any direct testing yet to see if this is the only change (sometimes changes in volume only can results in quite some perceived changes in quality), but I definitely hear a change when just enabling timestretching.

Bear in mind that if there’s a difference between the original length of your sample and the length of time that it takes to play the number of lines you’ve selected for Beatsync, then you’re going to hear a difference. When the times exactly match then there are some minor differences in the waveform that you can see if you render the stretched version out, but nothing audible that I can hear.


Yes i get the noises too specially in percussion mode

It’s not only the volume it changes , it affects the transients too , even when it’s not stretched .

right , but here its not the case

As a test do this:

Take the AmenBreak that comes with Renoise, set the BPM to 140. Enable beat sync and set it to 64. Then enable Timestretch (Texture). It sounds completely different than when you disable beat sync again.

Even weirder, after applying the beat sync settings to the tune and finetune settings, the loop starts correctly, but after 1-2 seconds changes in sound. If you look at the phase meter, you can see that there is a phase issue.

That’s because there’s a difference between the original length of that sample and the length of time that it takes to play 64 lines. It says 140bpm in the sample name, but the real length doesn’t fit exactly into a pattern of 64 lines at 140bpm. Instead, create your own beat in the Pattern Editor and render it, then the times will exactly match.


Such a small change, however, should not lead to such a drastic change in sound. As I said, there is something going on with the phase.

As i assume , time stretch changes the sound noticeably when too much you change pitch and tempo , but not right from the start when such a little change has taken place .

You also don’t hear any of these extreme phase issues in the Rubberband examples: https://breakfastquay.com/rubberband/examples.html

I just hope whatever said here are bugs which could be fixed in an update , otherwise renoise timestretch is not very useable .