On 3/14/19 7:25 AM, Sami Jumppanen wrote:
1) Two days ago: MIDI sequencer tempo went up during play, and it's not
a tiny increase, I'm guessing +10% or more.
So this points to ALSA / kernel? What should I try next?
I have clean Ubuntu Studio 18.04 install...
I just went through that whole reinstall debacle myself. This is
Kubuntu with a few ubuntustudio- packages installed, including the
kernel. When I start Rosegarden and start piddling with it, timing
seems fine. If the open Rosegarden sits around for a few hours, timing
just goes completely to hell. It's also pretty common for it to report
the message about the audio server stopped it processing audio, even
though jackd is still running, and isn't reporting xruns. This message
from Rosegarden used to occur when I shut down jackd while Rosegarden
was running. I have no idea why it's occurring now.
One time, I had to kill the jackdbus process after it started eating 60%
of CPU at idle, and everything short of -9 failed.
It's worth noting that this is a stock install with all the consumer
stuff still running, like some the bridge between pulseaudio and jackd.
That's how I had been running for the past several years, since it's the
only way to get audio out of online videos, and this box is my browsing
and surfing machine more than my music production machine these days.
Reading what I type: I have to double check the second Delta 1010LT, if
it's really synced to the first card. Both of the cards are used for
MIDI, and sync out from RG is connected to both. I would be happy to use
soundcard timer in my system all the time, if it just is reasonable option.
On a different machine, I have a Focusrite 18i20 synced to a Focusrite
Octopre via SP/DIF. My recordings from the Octopre had a strange noise
in the signal. It was part of the signal, it made its way into
recordings, and it was a very regular low frequency pulse. It was
subtle enough that I managed to filter it out. Later, I finally
realized that the two units were NOT in sync, and that weird artifact
was the result.
I have no idea if that's universally applicable or not, but my
experience would suggest that if all your recordings are clean of any
such regular pulsating noise, your two interfaces are probably synced
successfully. When I experienced this, I could hear the pulse in my
monitors while singing a note into any of the microphones that were
plugged into the slave unit.
2) Using RG to send MIDI clock with start/stop/continue, I noticed Korg
Volca Bass rush a few 16th in start, thus playing in advance (out of
sync wrt RG sequence). I don't know if this is anyway related, so I
though I will mention anyway. On other squencers I've used I guess they
send MIDI clock all the time, and add PLAY/STOP when needed, so there
was no rushing. Need to capture MIDI clocks or verify with other
MIDI-syncable systems.
I haven't tested MIDI sync at all.
--
D. Michael McIntyre
_______________________________________________
Rosegarden-devel mailing list
Rosegarden-devel@lists.sourceforge.net - use the link below to unsubscribe
https://lists.sourceforge.net/lists/listinfo/rosegarden-devel
