MIDI to USB latency problem - Linux-audio-user

22 May 2013

Hi,

I've not been active here for quite some time. So, I've tried something
simple to get my toe back in, as I need to distribute MIDI files to some
musician colleagues.

So, I've wired an old Yamaha 49-key keyboard into Fluidsynth using a
Textech MIDI to USB cable, and provided the aconnect command.

I have sound, but it's about 300 ms latent--effectively unusable.

Fluid synth did complain: "Failed to pin the sample data to RAM." Could
that possibly explain this much latency?

I'm loading Fluidsynth for alsa_seq because I don't believe I need the
complexity of jack just yet. But, might jack do better?

Any suggestions most appreciated.

Janina

Len Ovens writes:
...

 On Tue, May 21, 2013 11:31 am, Robin Gareus wrote:
  [message re-arrange to avoid top-posting]
 On 05/21/2013 04:52 PM, Axax wrote:
> On 05/21/2013 09:30 AM, Abhayadev S wrote:
>> Hi,
>>
>> Anybody had tried using the Focusrite Scarllet 8i6 on Ubuntu Studio 
13.04?
 >>
>> So far it was not supported under ALSA but from 13.04 it seems it is  been
detected and the JACK is able to list out couple of I/Os.
 >>
>> Last day i just booted up a live version of the 13.04 and was bale to  do
couple of i/o routing. Jack lists 8 inputs and 12 outputs. It seems
 the Inputs 1 to 4 (analog mic/line-ins) are listed as Inpiuts 1 to 4
 and 2 SPDIF are 5 and 6. But i am not sure about the 7 and 8. I am
 getting the same SPDIF signal on these inputs too !
 >> The output 1 to 4 are Monitors output
(1&2) and extra outputs (3&4) on  the backside of the box. And 5&6 seems
to be SPDIF outputs. Still have
 6 more outputs to be listed/clarified.
 >>
>> Just going ahead with further analysis and if anybody out there has  any
thing to add on please do so..
  >
> Regards,
> Abhayadev S
> http://sites.google.com/site/abhayadevs
> http://sites.google.com/site/astudioindia
> 
> Hi,
>
> I've the same audio card. It's working as you described, but I can't
 figure out hot to change the input mode for the channels 1-2 from MIC
 to LINE/instr!
 > Anybody have a clue?  
 Just a quick addition. The below describes how to change the
 line/instrument inputs back and forth. Mic to line is automatic. If you
 plug into the XLR it is mic mode and into the 1/4inch TRS (or TS) it is
 line/instrument mode.

 A.

 see

https://focusritedevelopmentteam.wordpress.com/2012/04/23/linux-and-focusri…

 https://github.com/x42/alsa-driver/tree/s18i6  adds full mixer support  for the
18i6. According to Focusrite the same will also work for the 8i6
 -- but I lost interest in Focusrite devices for various reasons.

 Short of patching the alsa kernel driver or using another OS to change  device
config, you can use https://github.com/x42/scarlettmixer to
 change the config on GNU/Linux. It's not a ready-to-use app, however:

 1) rmmod snd_usb_audio  # so that python script can access the device 2)  change
the python script line 31 to detect the 8i6
  3) tweak the "example code" line 492..
   the "line/inst" switch is there as sw_impedance()
 4) modprobe snd_usb_audio # ...

 best,
 robin
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 -- 
 Len Ovens
 www.OvenWerks.net

 -- 
 Len Ovens
 www.OvenWerks.net

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Janina Sajka,	Phone:	+1.443.300.2200
			sip:janina@asterisk.rednote.net
		Email:	janina(a)rednote.net

Linux Foundation Fellow
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