On Thu, 19 Dec 2013 11:15:06 -0200 Gianfranco Ceccolini <gianfranco(a)portalmod.com.br> wrote: I'm using a Komplete Audio 6 which seems to work out of the box. Level is maybe slightly on the low side but is very clean and not a hint of noise or distortion, so appears to have plenty of headroom. -- Will J Godfrey http://www.musically.me.uk Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song.

El 19/12/13 20:51, Jeremy Jongepier escribió: Yes, of course. This is what I've got now: /usr/bin/jackd -dalsa -dhw:0 -r44100 -p1024 -n2 This is without using the UCG-102 yet (which would be using hw:1), because I'm having a few issues with Pulseaudio, but it was the last working configuration. I confess I don't have much idea about finetuning Jack: I was usually happy just making it work. So, if you see something obviously stupid in this configuration, assume ignorance as first option :-) Thanks, -- Roberto Suarez Soto I need a hurricane To wash my sins away

On Thu, 2013-12-19 at 23:45 -1000, david wrote: -n3 should only be used, if -n2 shouldn't work. AFAIK -n3 will increase jitter, so the sound could become muddy.

On Fri, 2013-12-20 at 11:22 +0000, Fons Adriaensen wrote: I never tested it myself, however, I remember that it often is mentioned not to use -n >2. Is there a reason to avoid -n >2 or is t juts a myth? Regards, Ralf

On Fri, 2013-12-20 at 12:50 +0100, Jeremy Jongepier wrote: This doesn't answer my question [1], resp. IIUC there is _no_ drawback when using -n >2, if there would be a drawback, it would have been mentioned in the man page?! OTOH the default rate is 48000 Hz and for good reasons it definitive is the rate used for studio productions, but there's no hint not to use rates < 48000 Hz ;). It would be nice if you would share information, I guess this is what lists are for, it's not a battle ;). Unlikely that the Arch jackd manual page is incomplete, but I can't find further info there. [1] ALSA BACKEND OPTIONS -n, --nperiods int Specify the number of periods of playback latency. In seconds, this corresponds to --nperiods times --period divided by --rate. The default is 2, the minimum allowable. For most devices, there is no need for any other value with the --realtime option. Without realtime privileges or with boards providing unreliable interrupts (like ymfpci), a larger value may yield fewer xruns. This can also help if the system is not tuned for reliable realtime scheduling. For most ALSA devices, the hardware buffer has exactly --period times --nperiods frames. Some devices demand a larger buffer. If so, JACK will use the smallest possible buffer containing at least --nperiods, but the playback latency does not increase. For USB audio devices it is recommended to use -n 3. Firewire devices supported by FFADO (for‐ merly Freebob) are configured with -n 3 by default.

On Fri, 2013-12-20 at 13:35 +0100, Jeremy Jongepier wrote: Thank you, so my remembrance confused it with another sync issue. Regards, Ralf

Ralf Mardorf wrote: The buffer size is the product of the period size (-p) and the number of periods (-n). A larger buffer size increases latency, but reduces the risk of underruns. A smaller period size _slightly_ increases CPU usage because of the overhead needed for handling a period. Therefore, when optimizing for low latency, one typcially uses two periods and makes -p as small as possible. With USB devices, the period boundaries (where interrupts are supposed to happen) are not necessarily coincident with the USB frame boundaries (where interrupts actually happen). This results in delays (jitter) of up to 1 ms in the timing of period interrupts; with very small buffer sizes, this increases the risk of underruns greatly. So if, e.g., the machine is not able to handle "-p 64 -n 2" reliably, increasing the number of periods to 3 results in lower latency (3*64=192) than increasing the period size (2*128=256). (Using "-p 96 -n 2" would have the same latency, but works only if that particular Jack version allows period sizes that are not a power of two.) Regards, Clemens

On Fri, 2013-12-20 at 15:04 +0100, Clemens Ladisch wrote: Thank you too. Jeremy already posted a link to a thread where _you_ explained it :) (less detailed than now). Résumé: As Fons pointed out, the sound quality isn't affected by the -n size. I assume even sync between audio and MIDI, between several devices isn't affected by the -n size, but just some prosumer USB devices could cause less good sync between audio and MIDI, irrelevant for this thread. Regards, Ralf

On Fri, 2013-12-20 at 12:17 -0500, Egor Sanin wrote: _The OP asked about the used jackd settings, this implies that the OP want's to know if he/she is missing something._ So it wasn't me who captured this thread for something that is OT. You still could be right, OTOH you never know. A user reading this thread or even the OP might not think about such related things. Users might buy an interface for audio, to connect a guitar and another for MIDI. The thread _is_ only about connecting a guitar by audio, but somebody might read the thread in the archive, got all the information about audio interfaces for guitars and then is surprised when syncing a drum computer or similar isn't that good synced as expected. Regards, Ralf -- Windows 8 Pro floppy disk 1 http://lists.freebsd.org/pipermail/freebsd-questions/2013-December/255074.h…