Testing input and output

fejngold · 6 September 2022 12:13

Hello,
I’m new to Elk Audio OS and plan to create a simple delay effect for voice input. Therefor, bought a RaspPi4B and a HiFiBerry DAC + ADC Pro. Installing Elk Audio OS was easy, so was setting up Wifi. According to dmesg the Hifiberry hat is running to.

However, I’m struggling to test the SUSHI examples. Eg. I managed to start ** “sushi.testing.passthrough”** but won’t hear any difference when listening to my input on headphones.

Before starting deep diving into further error seeking, a general question:
Is there any way which allows me simply to test audio output (and input)?

Stefano · 7 September 2022 13:59

Hi @fejngold ,
the “passthrough” example does indeed what you mention: you would get on the headphones exactly what you pass as input.

If you want to test a real FX, try to check / adapt one of the example configuration files that use for example the MDA plugins, such as this one:

github.com

elk-audio/elk-examples/blob/master/multi-fx/elk_multi_fx_pi.json

{
    "host_config" : {
        "samplerate" : 48000
    },
    "tracks" : [
        {
            "name" : "main",
            "mode" : "stereo",
            "inputs" : [
                {
                    "engine_bus" : 0,
                    "track_bus" : 0
                }
            ],
            "outputs" : [
                {
                    "engine_bus" : 0,
                    "track_bus" : 0
                }
            ],

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fejngold · 12 September 2022 12:44

Thank you @Stefano, this helped me a lot. Finally, I got a first success by using your example. Also, I added the jumpers to the microphone input.

Now, I’m wondering how I can control length and feedback of the / an delay effect.

fejngold · 12 September 2022 15:17

I’m currently using mdaDelay.so from “plugins/mda-vst2/” as plugin.

Stefano · 13 September 2022 15:09

Hi @fejngold,
have you seen the plugins included in the community pack?

There are several other delay plugins e.g. in the Calf and Airwindows collections that you could try.

fejngold · 13 September 2022 15:29

Thanks @Stefano,
I will give those in AirWindows a try. However, Calf seems “lv2” and I failed running those so far.

fejngold · 13 September 2022 17:09

Okay, just had a second look into the community plugins. However, I’m having issues running lv2 plugins properly. When running the example file “config_play_lv2_jx10.json” I got the following error.

Failed to load tracks from Json config file

Probably something related to the URI.

Ilias · 14 September 2022 12:06

Hi!

Have you come across this (Lv2 plugin config files?) conversation on the forum?

An Elk-user recently also tried the LV2 examples and had some questions which we resolved in that thread - maybe it is useful for you as a starting point.

This reminds me we still haven’t updated the documentation for the plugin pack (GitHub - elk-community/elk-plugins-pack: Meta repository with all the available community plugins built for Elk Audio OS) to reflect that conversation, do keep that in mind.

Best,
Ilias of Elk

Edit: I just updated the documentation on the main plugin pack README.md, let me know if it is clear now.

fejngold · 14 September 2022 15:30

Thank you @Ilias. I followed your updated Readme and it worked like a charm and the lv2 plugins now serve their purpose.

(Might be good to explain the command “lv2info” there too.)

fejngold · 18 September 2022 13:59

Another question related to input / output while using the Hifiberry DAC+ ADC PRO. How could I address settings for gain or mic bias. Hifiberry documents those commands in its technical documentation and suggests to use amixer sset. However this seems not suitable for elk audio. Any suggestion how to solve this?

Stefano · 22 September 2022 12:04

HI @fejngold,
with Elk, the HiFiberry is not accessed through Alsa, so those commands won’t work.

You would need to tweak the driver here:

to apply similar settings.