Re: [fluid-dev] What is the best way start fluidsynth with zero/low latency?

[Louis B.]

Hi All,

Wow thank you all very much, I have been struggling with this problem
for years now trying to get low latency synth on linux. Poring over
the help and man pages trying to solve this problem many times but
with no luck. I just thought this is was how Linux was, things never
working quite properly.

the line did if for me is <q>you can try "plughw:0"</q>

the full command line that works for me on my net book is

fluidsynth -C0 -R0 -r22050 -l -o midi.alsa_seq.id=fs  -a alsa -o
audio.alsa.device=plughw:0 /usr/share/sounds/sf2/FluidR3_GM.sf2
/usr/share/sounds/sf2/FluidR3_GS.sf2

I have now got some decent sounds that are usable on my Piano (my
piano is not near my main computer hence the netbook.)

The only problem is that now the ubuntu volume controls to do not work
with the fluid synth audio (i have not tried all the things other
people suggested yet). But a least Piano Booster is now usable on
Linux for people who do not have a hardware synth. Brilliant!

I feel that it is important to present this information to non techie
users so that they will have a positive experience of Linux and of
fluid synth. I could put up a page (on the PB site) for getting low
latency for all the different distributions. So does that command line
above work on your distributions. If not please can you all post
__TESTED__ command lines that work for other distributions on the
lowest spec machine you can get your hands on. (I know there is Qsynth
but I had a bad experience of it with it crashing and like most users
I did not post a bug report).

I know there is also jack -- but that also just adds unnecessary
complication. I just want fluidsynth to work with low latency. There
should be a way to start jack automatically (and fluid synth for that
matter) behind the scenes without the user being aware of it. ie it
all just works. I am also not keen in integrating fuildsynth into PB
as i don't want PB to get bloated.

Oh dear, this has just turned into a bit of a rant but hopefully it is
all fairly positive. Thanks again, fluidsynth it is fantastic and I
really do appreciate all your hard work and I can fully recommend it
to others.

Thanks

L o u i s


PianoBooster is a MIDI file player that teaches you how to play the piano. see:

http://pianobooster.sourceforge.net/

On Thu, May 21, 2009 at 5:03 AM, David Henningsson  wrote:
> Louis B. skrev:
>> Hi all,
>>
>> I am the developer of Piano Booster and I have written some
>> instructions on how to start fluidsynth see this link.
>>
>> http://pianobooster.sourceforge.net/faq.html#how-do-i-hear-the-sound-on-linux-ubuntu
>>
>> However I cannot get fluidsynth to run with zero/low latency. I
>> estimated the latency delay  is about 100msec.  I can hear a delay
>> when I play on the Piano which is always a bad sign. I do not get a
>> noticeable delay when I play using an external synth. See this link
>> for more info on my set-up.
>>
>> http://n2.nabble.com/Poll---What-system-are-you-running--td2595879.html
>>
>> Please tell me what I have to do to  get fluidsynth to run as close to
>> real time as possible so that I can improve the instructions on the
>> PianoBooster web site.
>
> The recent Ubuntu versions will try to route things through pulseaudio,
> which introduces some latency. I would suggest you add the following
> options:
>
> -a alsa -o audio.alsa.device=hw:0
>
> Selecting the right alsa device could be a jungle for the novice, but
> shortly: where "hw:0" is the suggested sound output, it is "hw:0" for
> your first soundcard, "hw:1" for your second etc. If that fails with a
> message "could not find a suitable audio format", you can try "plughw:0"
>  instead of "hw:0", although that will increase the CPU consumption a bit.
>
> // David
>