(Question) Jack as an option on Fluidsynth audio.driver - RPi 3, Headphones

[elbolutony]

Hi, first, thanks for you work on this. (En is not my native language, sorry in advance) I've found/feel that the "real" latency is much less noticeable using jack as an audio driver than alsa. Thing is that using jack won't autostart fluidsynth on boot. It's possible? Secondary question: I'm unable to effectively modify the period one ./jackrc; (or whatever i do on fluidsettings.xml) "fluidsynth warning requested a period size of 64 got 444 instead" but i'll keep tinkering this,

Thanks!

[albedozero]

JACK should be started automatically by FluidSynth on boot. It seems the headphone jack cannot be used with a period size of less than 444, for technical reasons I don't completely understand. You can get lower with a USB sound card or sound card that connects to the GPIO.

Can you share the contents of your /home/pi/.jackdrc file and your /home/pi/SquishBox/squishboxconf.yaml file? That might help to figure out the issue.

[elbolutony]

Hi! Thanks for your reply. Sure, attached you'll find the files.

jackdrc (i'm aware of the 512 period, i'm testing)

/usr/bin/jackd --silent --realtime -d alsa --softmode --playback -S -i 0 -o 2 \ --device hw:Headphones --period 512 --nperiods 3 --rate 48000

squishboxconf.yaml

`# config file used by squishbox.py and headlesspi.py soundfontdir: SquishBox/sf2 bankdir: SquishBox/banks mfilesdir: SquishBox/midi plugindir: /usr/lib/ladspa currentbank: bank1.yaml

fluidsettings: # http://www.fluidsynth.org/api/fluidsettings.xml
audio.driver: jack audio.jack.autoconnect: 1 audio.jack.multi: 1 midi.autoconnect: 1 player.reset-synth: 0 synth.audio-channels: 16 synth.audio-groups: 16 synth.cpu-cores: 4 synth.ladspa.active: 1 synth.polyphony: 128 synth.sample-rate: 48000

fluidsettings-alsa: audio.period-size: 256 audio.periods: 4 midi.autoconnect: 1 player.reset-synth: 0 synth.cpu-cores: 4 synth.ladspa.active: 1 synth.polyphony: 128`

And: pi@raspberrypi:~ $ python3 headlesspi.py fluidsynth: error: Unknown integer parameter 'synth.sample-rate' Cannot connect to server socket err = No such file or directory Cannot connect to server request channel jackdmp 1.9.17 Copyright 2001-2005 Paul Davis and others. Copyright 2004-2016 Grame. Copyright 2016-2021 Filipe Coelho. jackdmp comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK server starting in realtime mode with priority 10 self-connect-mode is "Don't restrict self connect requests" creating alsa driver ... hw:Headphones|-|512|3|48000|0|2|nomon|swmeter|soft-mode|16bit configuring for 48000Hz, period = 512 frames (10.7 ms), buffer = 3 periods ALSA: final selected sample format for playback: 16bit little-endian ALSA: use 3 periods for playback fluidsynth: Jack sample rate mismatch, adjusting. (synth.sample-rate=44100, jackd=48000) fluidsynth: Connection of Midi Through Port-0 succeeded fluidsynth: Connection of K61P MIDI 1 succeeded Connection is already subscribed Connection is already subscribed Loading bank 'bank1.yaml' .. fluidsynth: error: Unknown integer parameter 'synth.sample-rate' fluidsynth: warning: Sample 'SineWave': ROM sample ignored Bank loaded. Selected patch 1/26: Piano fluidsynth: Connection of K61P MIDI 1 succeeded

That will be all.

[albedozero]

The lines

JACK server starting in realtime mode with priority 10
creating alsa driver ... hw:Headphones|-|512|3|48000|0|2|nomon|swmeter|soft-mode|16bit

show that the JACK server is indeed being started by FluidSynth. JACK uses ALSA as a back-end driver, but it is running and enforcing lower-latency audio. Are you getting sound output?

The fluidsynth warnings about Unknown integer parameter 'synth.sample-rate' are because the sample rate should be a float: 48000.0 for example. This isn't breaking anything - fluidsynth adjusts its sample rate to match the 48000 you requested from JACK.

[elbolutony]

It runs ok, sounds ok, but not autostarting on boot, i have to run it manually. Running it with alsa instead of jack leads to a bigger latency, i've couldn't keep playing with some songs. Cheers

[elbolutony]

Ok, i took your comment;

This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details JACK server starting in realtime mode with priority 10 self-connect-mode is "Don't restrict self connect requests" creating alsa driver ... hw:Headphones|-|480|2|48000|0|2|nomon|swmeter|soft-mode|16bit configuring for 48000Hz, period = 480 frames (10.0 ms), buffer = 2 periods ALSA: final selected sample format for playback: 16bit little-endian ALSA: use 2 periods for playback fluidsynth: Connection of Midi Through Port-0 succeeded fluidsynth: Connection of K61P MIDI 1 succeeded Connection is already subscribed Connection is already subscribed Loading bank 'bank1.yaml' .. fluidsynth: warning: Sample 'SineWave': ROM sample ignored Bank loaded. Selected patch 1/26: Piano

i managed to get this without noticeable xruns (except on the start).

[albedozero]

Did you install using curl -L git.io/squishbox | bash? What happens when you enter

sudo systemctl status squishbox.service

[albedozero]

You can get fewer xruns by dropping the sample rate in .jackdrc to 22050 - you're not really losing anything since the headphone jack can't reproduce the high frequencies that well anyway.

[elbolutony]

pi@raspberrypi:~ $ sudo systemctl status squishbox.service ● squishbox.service - Headless Pi Synth Loaded: loaded (/etc/systemd/system/squishbox.service; enabled; vendor preset: enabled) Active: active (running) since Sat 2022-02-19 03:05:20 GMT; 9min ago Main PID: 394 (python3) Tasks: 8 (limit: 1597) CPU: 4.624s CGroup: /system.slice/squishbox.service └─394 python3 /home/pi/headlesspi.py

Feb 19 03:12:49 raspberrypi sudo[906]: pam_unix(sudo:session): session closed for user root Feb 19 03:12:50 raspberrypi sudo[909]: pi : PWD=/home/pi ; USER=root ; COMMAND=/usr/bin/tee /sys/class/leds/led0/brightness Feb 19 03:12:50 raspberrypi sudo[909]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=1000) Feb 19 03:12:50 raspberrypi sudo[909]: pam_unix(sudo:session): session closed for user root Feb 19 03:12:50 raspberrypi sudo[912]: pi : PWD=/home/pi ; USER=root ; COMMAND=/usr/bin/tee /sys/class/leds/led0/brightness Feb 19 03:12:50 raspberrypi sudo[912]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=1000) Feb 19 03:12:50 raspberrypi sudo[912]: pam_unix(sudo:session): session closed for user root Feb 19 03:12:50 raspberrypi sudo[915]: pi : PWD=/home/pi ; USER=root ; COMMAND=/usr/bin/tee /sys/class/leds/led0/brightness Feb 19 03:12:50 raspberrypi sudo[915]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=1000) Feb 19 03:12:50 raspberrypi sudo[915]: pam_unix(sudo:session): session closed for user root

Not sound whatsoever.

[albedozero]

Aha - it was a bug. This line missing from the install script meant that JACK could not be started automatically. You should be able to fix this by running the install script again

curl -L git.io/squishbox | bash

Answer no/no change to all options except for "What script should be run on startup?" - answer headlesspi.py and it will overwrite the unit file and should work when you restart!

[elbolutony]

Cool, now it's starting on boot! Magnificent. Thanks again, i'm closing the issue.