Missing Chorus FX

[emlyn]

It looks like there are traces of a chorus effect in the code, but it's commented out here.
What's the reason for that, and what would it take to add it back in? I think it would be quite a nice effect to have available.

[ethancrawford]

I don't remember exactly, but I think there was no technical reason it couldn't now be included. @xavriley may be able to remind me 😉

[xavriley]

Yes! Chorus is a delay effect so it needs a buffer (a small space in memory to hold the delayed samples). At the time it was written, Sonic Pi didn’t have much in the way of buffer management. I remember that if you tried to allocate local buffers within the supercollider synth e.g. in a tight loop, it could lead to crashes. The better option would be to allocate the buffer beforehand and then pass the buf_id to the synth. I’m not sure but we might have some other synths that do that now On 25 Nov 2020, at 00:22, ethancrawford <[email protected]> wrote:  I don't remember exactly, but I think there was no technical reason it couldn't now be included. @xavriley<https://github.com/xavriley> may be able to remind me 😉 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#2557 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AAC2G574NBMEHTJ5ZLXW6FLSRRE4DANCNFSM4UBM7VKQ>.

[ethancrawford]

I’m not sure but we might have some other synths that do that now

I can't remember off the top of my head... but it's certainly not hard. In my emergent behaviour synths, I pass in the buffer id of the random number buffer that Sonic Pi pre-allocates for rand etc...

[emlyn]

Presumably echo, reverb and gverb are also delay effects? I don't see any buffer being passed into any of them though, so it's not really clear to me how that should be done. Also, does that mean that these fx could be made more efficient by creating the buffer outside and passing in the id?

[ethancrawford]

I don't see any buffer being passed into any of them though, so it's not really clear to me how that should be done.

Here is a link to the code where I do this for my emergent behaviour synths:
https://github.com/sonic-pi-net/sonic-pi/pull/2518/files#diff-cbd476b53987e2b30ecbc3bdf15ba74b631d4e1f57e00bf0ba44e129e5de19d6R3392-R3394

Also, does that mean that these fx could be made more efficient by creating the buffer outside and passing in the id?

@emlyn - for echo at least, as you may have seen, it is based on the CombN UGen:
https://doc.sccode.org/Classes/CombN.html
(There is alternatively a BufCombN UGen which does use a buffer for internal memory).
Whether either is more efficient though - I have no idea 🙂

https://github.com/sonic-pi-net/sonic-pi/pull/2518/files#diff-cbd476b53987e2b30ecbc3bdf15ba74b631d4e1f57e00bf0ba44e129e5de19d6R3392-R3394