On Thursday 17 April 2014 06:09:56 david did opine: > On 04/16/2014 02:54 AM, Gene Heskett wrote: > > On Wednesday 16 April 2014 08:44:15 david did opine: > >> On 04/15/2014 03:17 AM, Len Ovens wrote: > >>> On Tue, 15 Apr 2014, James Mckernon wrote: > >>>> On Mon, Apr 14, 2014 at 2:06 AM, Len Ovens <len@xxxxxxxxxxxxx> wrote: > >>>> I would realy like to stay away from having to use a USB or > >>>> FW audio IF. In fact I would like to be able to continue to > >>>> use my delta 66 for as long as I can before I spend more > >>>> money :) The > >>>> > >>>> Thanks for the useful info in your post. Just to be clear on this > >>>> part: are > >>>> you saying you don't want to switch to USB/FW solely because you > >>>> want to keep using your delta 66, or because you have some > >>>> definite preference for > >>>> PCIe over USB/FW devices? If the latter, I wonder why? > >>> > >>> USB in audio is limited. Getting clear USB ports interrupt wise is > >>> not easy. Audio can not be on a hub or share it's usb with anything > >>> else, but many new MB have no mouse or kb port so the USB is > >>> already being used for that much. The real reason though, is > >>> latency. With the pci the latency can be 1/4 what it can be in USB > >>> or FW. That is the lowest seeting jack for USB or FW is 64/2, but I > >>> can run the d66 at 16/2 with no problem on a well tuned system. > >>> This does make a difference for live work. I know that 64/2 seems > >>> like very good latency (it is) but remember that the card then adds > >>> another ms in each direction as well as the stage distances on top > >>> of that. That is the time it takes the sound to reach my ear after > >>> going through the computer as a processor and then through the air > >>> to my ear. Maybe that is still not worth worrying about... but even > >>> with 30 feet of cord and no digital delay, I can hear the delay > >>> from my playing to the sound reaching my ear. > >> > >> Interesting. What is the difference between speed of sound in air and > >> the speed of electricity through a cable? > > > > Sound is nominally 720 miles per hour. Rather leisurely IOW. > > A perfect cable is C speed, 258 times faster. But cable (coaxial) > > actually range in speeds between 66% of C for home usable cables, to > > around 98% of C for 9" diameter high power broadcast stuff, C being > > 186,272 miles per second in a vacuum. Thats 298,035.2 kilometers per > > second for the metric folks here. > > Then running your sound from stage to backhouse sound board back to > stage and hearing it through headphones would give no latency at all. For an analogue board, small fraction of a millisecond, for a digital board, anybodies guess. A/D and D/A's are essentially pretty quick, but I'd still put most digital boards above a millisecond. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user
