Hi Rui :) thank you. Since I retrieved and wrote emails 2 weeks ago, I made music using Qtractor.
Rui Nuno Capela wrote: > [snip] > > can't say anything really useful atm. > > i think the issue is due on jitter wrt. internal vs. external midi. i > mean, internal midi is what triggers midi intrument plugins (eg. dssi), > external midi is what goes through alsa-seq output queue then to outboard > synths. it is a fact that this latter kind of midi flow is subject to > jitter which may vary environmentally (eg. timer used by alsa-seq, kernel > scheduler and system workload, midi output device throughput, usb or plain > old current-loop midi cables? add all that to fixed latency of midi > triggered synths and audio turn-around, which you're probably recording > and/or rendering in real-time. depending on all of this accumulated > amount, phasing or delay effect should be audibly expected on the > monitors. > > you see, there's too may variables involved on this out-of-sync issue, > when dealing with external midi stuff. most probably you cannot get rid of > the latency. you should take jitter to a minimum though. that's the one > and real problem. > The external MIDI and audio equipment is well cultivated partway self-made home recording equipment (as I often wrote, I was working for a well known manufacture for studio equipment at development and manufacturing), no problem is caused by this. Using the Atari ST and analogue tape, there is no jitter and no sync problem, and no means no. I still didn't test the mobo so hard whit Windows. I only installed Windows because of the rt-audio troubles I've got when running Linux. At the moment I still have to join to older reports I made. 1. I needed to increase jackd's 'p' option to 512, to be able to go on working. For the mastering I'll increase 'p' again, because there are still xrun like sound effects. 2. An easy and modest test song that still isn't finished, nearly needs 100% CPU, while the sound quality of the mixing still isn't professional. A heavy mixed Windows test-song needs less than 80% CPU and the mixing (nearly) has professional sound quality. 3. I recorded electric guitar and external MIDI equipment at lower 'p' than 512, but I needed to manually fix the timing by editing note for note, something that for most recorded material isn't possible. Resume for the moment: Usage of Qtractor with DSSI and LADSPA cause no jitter and no problems with sync, but until now I wasn't able to finish and mix a song, there is trouble because of the CPU load and still the mixing quality is bad. Recording external equipment not only MIDI, but also guitar, vocals etc. isn't possible because of bad sync and jitter. Just to check if my computer hardware is fine, I compare Linux with Windows! (I'm not dissing Linux and I never came from Windows) On Windows latency on heavey usage of VST and VSTi is lower than it is for DSSI and LADSPA on Linux for minimal usage. On Windows CPU load at heavy usage of VST and VSTi is lower than it is for DSSI and LADSPA on Linux for minimal usage. On Windows the sound quality of the mixing by using VST and VSTi is (nearly) professional, but bad when using Linux with DSSI and LADSPA. It might be possible to get a good sound quality using Linux on my machine too, but it has to be said, I run Windows for days testing rt-audio productions and Linux for years testing rt-audio productions. I never heard a Linux production made by someone else, that was a mix of DSSI, LADSPA and external equipment, but all mixed in the box, that had a professional sound quality (links to music done in such a way are welcome and hints which LADSPAs are fine and which have a bad quality etc. are also welcome). I still will try to remix the unfinished test-song and try to get a good sound quality. I don't think I'm the only one having trouble with sound quality, someone from the 64 Studio list made a mixing that is very well done, but anyhow it sounds like a 4-track tape recording and not professional. He decided to master his recordings at a professional mastering studio. My involuntary choice would be Windows :(, instead of a professional mastering studio. I don't know if Windows is fine with sync and jitter for external equipment or if it will be the same like it is for Linux, but even if it should be like it's for Linux, it's still possible to keep the latency lower with Windows and I guess a lower latency on Windows will have the same positive effect on jitter and sync, it has got for Linux. >> By the way, here is the output of rcirq: >> >> http://lists.64studio.com/pipermail/64studio-users/2009-June/003054.html >> >> > > if your primary audio interface is the "usb" one, try to put it ahead of > the "snd" in the priority sequence--see your rtirq.conf, like this > > # IRQ thread service names > # (space separated list, from higher to lower priority). > RTIRQ_NAME_LIST="rtc snd usb i8042" > > change that to: > > RTIRQ_NAME_LIST="rtc usb snd i8042" > > and restart. > > byee No, my primary sound device is an Envy24 based PCI card. The USB device is for MIDI only. I guess once upon a time I got better sync and/ or less jitter when not using RTC or what clock ever, but sync to PCM output or what it is called for Rosegarden's sequencer clock. Cheers, Ralf _______________________________________________ 64studio-devel mailing list [email protected] http://lists.64studio.com/mailman/listinfo/64studio-devel
