I agree that JACK doesn&#39;t seem to add any latency. The thing is, if Pd alone and Pd + JACK end up having the same latency, I don&#39;t see why i should bother running two programs. <br>Yet, I&#39;m not sure about Pd&#39;s latency. I know that the &quot;Delay&quot; in Audio settings doesn&#39;t seem to mean anything realistic at all (correct me if i&#39;m wrong). I can&#39;t push it below 8 ms without running into intolerable audio drop-outs, even though JACK is able to run at a latency below 5 ms. As I said, my ear isn&#39;t fast enough to detect any difference between both setups. So i guess I&#39;ll just try the program that was mentioned in one of the previous messages. <br>
<br>I also have another question. For now only pd vanilla is installed on my laptop, because ubuntu studio packages don&#39;t include pd-extended (which by the way is difficult to understand, given all the kind of useless and sometimes redundant apps they do provide). So, say I installed pd-extended, do you think i&#39;ll have to tweak something in order to get the same performances as with vanilla (stuff like adding it to the audio group, changing the rt, buffersize, etc...)?<br>
<br>Incidentally, Ubuntu 10.04 LTS installed very quickly and without any particular issues. It also starts and stops in no time. The only drawback is (as usual) that the wireless card doesn&#39;t work properly out of the box.<br>
<br>Thank you all for your help and advice!<br><br>Pierre  <br><br><div class="gmail_quote">2010/11/17 Raphael Raccuia <span dir="ltr">&lt;<a href="mailto:rafael.raccuia@blindekinder.com">rafael.raccuia@blindekinder.com</a>&gt;</span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">

  
    
  
  <div bgcolor="#ffffff" text="#000000">
    <br>
    <br>
    Le 17. 11. 10 03:36, Martin Schied a écrit :
    <div class="im"><blockquote type="cite">
      
      
      On 15.11.2010 23:06, Raphael Raccuia wrote:
      <blockquote type="cite">
        
        <br>
        <br>
        Le 15. 11. 10 22:21, Pierre Massat a écrit :
        <blockquote type="cite">Hi,<br>
          I have installed Ubuntu 10.04 LTS, plus some ubuntu studio
          stuff (the audio packages and the plugins). I also tried the
          rt-kernel. It didn&#39;t work.<br>
          But i am amazed, blown away, baffled, etc. Because the generic
          kernel does have some crazy rt capabilities indeed. I guess
          the ubuntu studio packages must have created the audio group
          and jack must have written the proper things in the limit
          file, but still, it works surprisingly well. Jack can run in
          rt with a latency as low 4 ms without any xruns, although it
          crashes.It works just fine at 5.33 ms. Even pd itself work
          with an extremely low latency (I&#39;d say below 7 ms), I&#39;m
          assuming that&#39;s because it was configured to run in rt during
          the install. <br>
          I don&#39;t even know if i need JACK anymore.</blockquote>
        jack don&#39;t add latency, and it&#39;s a powerfull sound server... you
        can connect pd to the outputs of your sound device and/or other
        sound/midi softwares, then you can save a patchbay to recover
        your patch... it&#39;s one of the most interesting stuffs on linux.<br>
        <br>
      </blockquote>
      it does add latency in most cases. you specify the amount of
      latency by using different period sizes and numbers of periods
      settings. But you can use very small buffers on some systems with
      good audio hardware, so they have the same size you would use
      inside pd in standalone (64samples). In this case you will not
      have more latency using jack than using pd standalone. (I&#39;m also
      only 99.9% sure about this, beware.).<br>
    </blockquote></div>
    From <a href="http://jack-audio.org" target="_blank">jack-audio.org</a><br>
    <h2>&quot;Doesn&#39;t use JACK add latency?</h2>
    <p>
      There is <i>NO</i> extra latency caused by using JACK for audio
      input and output. When we say none, we mean absolutely zero. The
      only
      impact of using JACK is a slight increase in the amount of work
      done
      by the CPU to process a given chunk of audio, which means that in
      theory you could not get 100% of the processing power that you
      might
      get it if your application(s) used ALSA or CoreAudio
      directly. However, given that the difference is less than 1%, and
      that your system will be unstable before you get close to 80% of
      the
      theoretical processing power, the effect is completely
      disregardable.&quot;<br>
    </p>
    <p>but of course, if you just run pd, you don&#39;t need it and you can
      set latency into pd, I forgot that. I mostly interface pd with
      other soft ( ardour or any recorder, midi sequencer, some plugin
      via jack-rack or calf etc...), and I plug midi controllers, but
      you can do it in qjackctl without running jack (alsa tab in
      connection window)...<br>
    </p><div class="im">
    <blockquote type="cite"> <br>
      Practically speaking - on systems I used until now I could always
      achieve lower buffer sizes using pd standalone and thus get lower
      round trip delays too.<br>
      <blockquote type="cite">
        <blockquote type="cite"> I couldn&#39;t tell by ear which config was faster,
          Pd alone or Pd plus JACK. <br>
        </blockquote>
        maybe I&#39;m wrong, but I thing only jack can provide rt...<br>
      </blockquote>
      you can run pd with the -rt flag, without jack. fo me it has
      proven to be far more stable at the lowest possible latencies than
      using jack. but this depends on your setup too. I don&#39;t use jack
      when I don&#39;t need it.<br>
      <br>
      Martin<br>
    </blockquote>
  </div></div>

</blockquote></div><br>