New prospective user with some questions

I don’t have a Zynthian yet but I am excited about the possibilities. I have some questions though:

The big one is how good is convolution reverb performance? I see that KlangFalter is listed as being compatible, but how does it perform on Raspberry Pi 4 based Zynthian? What’s the reasonable limit on the IR length?

I’m hoping to use Zynthian for processing of external audio so the latency matters. I have some instrument body IRs that I’d like to be able to load in KlangFalter and use live which means I’d be using it wet only. Because of this the latency of KlangFalter is much more important than if it was being used for reverb (where a bit of plugin latency just increases the pre-delay of your reverb).

Even if it’s not so good for these things, I’ll still want a Zynthian but it won’t be quite so urgent.


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These are difficult questions to answer directly.
It really is a matter of personal assessment. The appraisal could be made with a USB audio interface and a Pi4B but if latency is an issue I would suggest using a hifiberry card.

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I’m thinking of getting the official kit, so that would be using a hifiberry card, right?
But my question about performance isn’t about latency, it’s more about whether the Pi4 has enough horsepower to do realtime convolution and what sort of IR lengths I could expect it to cope with?

Hi @SirPrimalform. Welcome to the Zynthian community.

If you have a Raspberry Pi you can try this out yourself by installing the Zynthian image and using webconf to configure it to use non-standard configuration.

Are you already familiar with KlangFalter? If so then post up some settings and maybe someone can try them out for you.

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Only a Raspberry Pi 2, which is significantly weaker than the 4. I’d only be buying a 4 to make a Zynthian box.

That’s a good idea. I’m not familiar with KlangFalter yet, I only found out about it by googling “Zynthian convolution reverb”. My normal way of loading IRs is ReaVerb in Reaper.
I need to learn more about LV2 plugins, but maybe I can find a way to load it on Windows so I can post some settings to try.
I have one impulse response which is 20 seconds long! It’s the impulse response from an old piano with the dampers off. That’s the extreme end of things though.

I am doing a quick check now. The LV2 loads without any impulse loaded. Need to access its GUI, e.g. via VNC to select an impulse wave file. I downloaded a free pack from Free Reverb Impulse Responses | Voxengo and tried to load the largest, St Nicolaes Church.wav. The UI locked up and the CPU shot up to 100%. I removed and reloaded the plugin and added a small impulse, Deep Space.wav which is 0.16s. This seemed to load but I had an issue with monitoring. Subsequent attempts to load the same file gave 100% CPU so I am not confident that it will work well.

I wonder if anyone else has used this on the Zynthian?

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Thanks for trying, I really appreciate it!
When I made the thread I was just hoping to catch the attention of someone who’d already tried it (successfully or not). I had a feeling that convolution might be a bit too heavy even for a RPi4 but I thought I’d ask since it was on this list which I took to imply someone had had some success with it at some point.

This is an area we are looking at. We have started some benchmarking but have not validate all applications yet.

Oh well, this hasn’t dampened my enthusiasm very much. I still want one for all the stuff I know it can do!

Although it would be an essential purchase with the convolution reverb, it’d just be a fun thing to have without so it falls down my list of priorities somewhat.

Ah! Finished work and plugged in my guitar. Stopped Zynthain and tested the LV2 directly and it works really well. CPU is low for all the impulses I tried and sounds good. (So good that my musical son came running down the stairs to compliment me on the sound - praise indeed!) I then restarted Zynthian and it woks just as well. I am not sure what the issue was earlier but it works fine now. It could do with some consideration of how we load impulses. Currently you seem to need to do so manually from the GUI. I haven’t figured out how to make the presets work but nothing is beyond this excellent development team.

I am really glad you pointed this out to me. It sounds great. (My guitar is driving the Hiiberry into analogue distortion which is not ideal but it sounds nice!) I might just spend some time figuring out how to enable presets.

If you have an impulse you want me to test then send it over and I will let you know how it performs.

[Edit] I can see why presets aren’t working fully. The impulse file path is not quite right. That can be fixed. Next is to find some freely redistributable impulse files that we can package as a set of presets…

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Come on this has got to be worth a :face_with_monocle:

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And don’t think I haven’t got my eye on you too @SirPrimalform for a :face_with_monocle:

Oh, that’s great news!

I can upload the aforementioned piano IR (which is about 19 seconds long and works as a low level wash reverb) as well as some instrument body IRs (upright bass, acoustic guitars). For the instrument body ones you’re using it more like an IR based cabsim, so it’s 100% wet and needs to be as low latency as possible.
The piano IR I recorded myself and would happily allow it to be included in a preset if you wanted it. The others I’m not sure about - they were free to download but I can’t remember where I got them and therefore who you’d need to ask about including them.
I’ll upload them when I get back to my computer.

A whowhatnow?

Give the man a chance. He’s not even got a Zynthian yet!


I’ you I’m after first @riban, stop dodging the issue

. . . .

@SirPrimalform just press on the frown icon to get the story. . .

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I spent some time trying to get presets working in KlangFalter but it is bust. The LV2 dates from 2016. I added to an issue at DISTRHO but not sure if anyone is going to do much. I can’t get it to reload impulse files from the preset and switching preset crashes the LV2. Looks rather flakey. Note that this is not a Zynthian limitation but the LV2 implementation of KlangFalter.

Sorry @wyleu but this renders the plugin rather ineffectual. I have spent too long trying to get this to work and lost my musical mojo so no :face_with_monocle: for you today.

AAh shucks, I’ll have to go and hunt in interplanetary space then . . .

Most extraordinary

I never realised that was a cover . . .

The original… which I have to say I prefer but the cover is extraordinarily accurate . . .

I wonder, was it the band or the record company insisting …?

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