Changing audio playback speed


first post here, and I have to say that your project is awesome. With that out of the way, I’ve tried to change the playback speed of an audio file but failed.

It is mentioned in the 2211 release release that

 ... you can use it as a basic sampler, recording and using midi notes to play the recorder audio at different “speeds”.

but I couldn’t find to what it referred exactly. That might be my first miss. If somebody could develop what was meant by this, that would be cool.

Then I tried the “Rate shifter” audio effect and added it to the audio player chain. Problem solved ! But, no, the rate shifter couldn’t keep up with the audio, so the audio had cuts and was not usable. I guess that’s not expected, and maybe something need to be debugged here ?

The context here is “simple” piano practice with pianoteq as the driver and an audio file as a accompaniment. Ideally, I can change the speed of the accompaniment to adjust to my current (low) level.

And because a lot of different questions in the same topic make a lot of sense … I couldn’t find how to trigger the playback while the pianoteq lv2 chain was selected. The learnt midi button I assigned for playback was only available when I switch to the audio player. I guess I miss something here.

Thank you again for this project and let me know if my question needs more details,

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Hi @chemlecouscous

Welcome to our house of games. I don’t think we currently have a method to do what you want. I believe you want to be able to play an audio file, at a different speed but at the same pitch as the original. None of our current modules do that (well). I would recommend you create a copy of the file and time stretch it using an external tool, e.g. Audacity. Then you can play it with the audio player or (with a bit of fiddling) samplv1. (I have used Audacity to create pitch shifted versions of songs to allow a singer to chose which best suited her vocal range before we rehearsed but this is kinda the opposite to what you want.)

You can use MIDI learn to assign a MIDI CC to a control including the player transport but if you are in “Omni-On (Stage)” mode then this only works for the selected chain. Change mode in admin menu to “Multi-timbral” and re-learn the MIDI CC and it should do what you want.

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Hi @riban,

oki, that part I can do, and will be good enough.

That part eludes me totally. I’ve watch the samplv1 tutorial from “unfa” and try to look into it from an zynthian perspective, but that led me nowhere. Is there some other pointer I could look into to better grasp what you meant here ? (“no” being a perfectly reasonable answer)

Ah, that’s it.

Thanks for the reply, appreciated.

I would suggest sticking with Audio Player for now. samplv1 is not well integrated with Zynthian yet. (It is on the todo list…). So you should be able to play your audio that you have created externally using a MIDI CC to start/stop the playback. I feel this is a win!

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But why does the manual page say the audio player has this beat functionality that can change the speed without changing the pitch?

Hi @robert!

I have updated the audio player docs for the new version in oram development branch. It is awkward keeping the docs up to date. I did previously try to implement a dev docs area but that hasn’t happened this time. Sorry!

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