On Sun, Oct 25, 2009 at 11:37:43PM +1300, Chris Edwards wrote: > fons@xxxxxxxxxxxxxxx wrote: > > The dynamic behaviour of jkmeters (and also of the VU and > > PPM meters in jmeters) is very strictly defined. The values > > that are displayed are calculated in a way that does not > > depend on the display update rate, and (within reasonable > > limits) also not on the Jack period size. A level meter > > would just be useless eye-candy otherwise. [...] > > > Ah, thank you - very illuminating (and reassuring) answers. You > certainly see meters around (in consumer hardware, as well as software) > that you just know are really nothing but eye-candy! ;) Yes. In many cases they just serve to indicate the presence of a signal, so it doesn't matter much. It does for mixing, live recording and mastering. > The VU meter is I think another interesting example of the > cheap-and-easy in the analog domain Real VUs were not cheap, as the meter movement had to be designed to have the right ballistics which also made it more delicate than most plain Volt or Ampere meters. In the analog days all consumer tape recorders had 'VU' meters but almost none of them were anything close to the real thing. > being quite different from the > cheap-and-easy in digital. I've personally never used a hardware VU > meter in recording, so to me, DPMs seem like the traditional meter type, > and the averaging ones are the new-fangled ones. :) I've also not used them very much. Again back in the analog days in the US everyone used VUs. In Europe 'official' broad- cast organistations (under the influence of the BBC which was setting technical standards at the time) used mostly pseudo-peak meters, while private music studios mainly had VUs. British mixing desk manufacturers always offered the choice between VU and PPM. For a sound engineer switching between the two could be hard, as many (at least in the 'pop' music scene) where using 'tape compression' on some tracks as part of their technique. > As for meter refresh rates, I always appreciate a user setting for this > - though theoretically I guess you could do things like determining the > display hardware's refresh rate and varying the refresh rate depending > on reserve CPU capacity. Jkmeters has the -rate option. The default is 30, not 25 as I wrote before. Don't worry too much about CPU use. Only the part of the coloured bar that changes gets redrawn, this means less at higher update rates, and even that operation is just a copy from a precomputed image. Update rate could matter for a remote X connection via wireless. Ciao, -- FA _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
