>>>>Now I'm ""working"" with a Creative Audigy card and I want to buy a new >>>>one basically because Audigy doesn't allow realtime monitoring through >>>>jack (the latency is at least 45ms and for me is too much) and because >>>>I want to have a good dynamic response to record my acoustic guitar >>>>(now it saturates the input or I must record at a low volume with a lot >>>>of noise). >>>> >>>> >>>Very strange that you cannot achieve better performance... I don't know >>>the audigy, but with a crappy sb128 on athlon 800 w 256Mb ram I can get >>>with "reasonably few" xruns to 23 ms and even to 11 (i speak of the >>>values reported by qjackctl) - I suspect that your problem comes from not >>>having an external mixer for conveniently routing of inputs and outputs >>>and for monitoring what you are playing. >>> >>>Could also be a problem of a not enough powerful pc? >>> >>> >>it's not a problem of the pc: 2.6Ghz, 512Mb ram >>it's a problem of *me* configuring it... :( >>as Free knows, I already suspected that I had some problems with my jack >>configuration so this comments are the definite proof of it. >> >>Indeed, I *could* configure qjackctl with a latency of 23ms(periods: 2, >>frames: 512 ): but I when I used Ardour I got some problems like the >>sound getting cut sometimes, it hanged often, strange inicialization >>errors, etc. >> >> > >You may want to use a different configuration for different situations. For >multitrack recording, obviously go as low as poss without xruns (256 >Frames/Period - x2 works for me on a Celeron 600 + 256M). For dsp and mixing >it's worth allowing a longer period (1024 works for me). > > > >>Also I though that I shouldn't allow any "xrun" and I disabled "Soft >>Mode". Now I see I "must" allow "xruns" but what criteria do I follow? >>how much "xruns" can be allowed? >> >> > >It's not really how much xruns, it's more where they occur. Right in the >middle of an important take is bad. If they only happen when you're messing >about onscreen then you just have to discipline yourself to keep your hands >off the mouse. Really you don't want any [ha!], but having Jack exit every >single time you hit an xrun can be equally annoying. > > > I finally realised what was happening. the configuration (periods: 2,frames: 512 -> 23ms) is fine for jackd and I only get a few xruns when I'm under gnome. HOWEVER ARDOUR(I use beta19) does strange things when working under low latency. After some minutes, I begin to hear strange noises (similar vynil at the begining) and then the music totally turns into noise. Experimentally I saw that this effect disappears when I "save" with Ctrl-S!!! And for other usual things ardour also hangs a lot. I don't know if there's other people having the same problems, I'll try on ardour's list... That's why I though it was jack or my sound card which didn't support that latency, but after your comments I gave it a try again and I discovered the "Ctrl-S dirt trick"... >>And finally, to tweak jack configuration, I ignore if it can be useful >>to change other parameters. >>Now I only play with "periods" and "frames", and I don't know the exact >>influence of the parameters: "Start Delay"(why jack has an initial >>delay?) and "Timeout"(of what? it sounds the same than latency...). I >>didn't found docs about jack about these issues... Does anybody know? >>Should I try the jackit user list or it is too technical? >> >> > >I have a start delay of 2 secs and a timeout of 500ms. The former gives Jack >longer to start up - I assume it allows the prefilling of buffers or somesuch >[?]. The latter means it waits longer before giving up. AFIU > > > uhm. I continue to be a little bit confused about "Start Delay" and "Timeout". 1)I don't understand why "Start Delay" is configurable if it only affects the initialization of jack. 2)Timeout refers to what kind of wait? when there is a xrun? By the way, I realised that jack has only a developpers list. Am I going to survive after writting to that list asking for those parameters? >>If there isn't documents on these questions, when I'll finish, I'll try >>to write it down and make a "beginner's" doc. >>Also I think that it should be a place where the people could post their >>experiences in different sound cards in linux and their jack >>configurations under different environments. This should make our life >>easier... >> >> > >I assume you're familiar with: >http://www.agnula.org/download/demudi/1.2.0-FAQ > > >http://wiki.agnula.org/ is a good place to start work on additional >information that is needed. It would be brilliant if more people used it ;) > > great. I didn't know that one. It seems to be quit new. isn't it? >cheers > >tim hall > > thanx!
