On 04/17/2014 12:37 PM, Gene Heskett wrote:
On Thursday 17 April 2014 18:18:05 david did opine:
On 04/17/2014 12:13 AM, Gene Heskett wrote:
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.
That's interesting. We're looking into replacing the analog board with a
digital one.
We replaced an old 12 stereo channel 48 input logitek analog board,
couldn't keep ahead of replacing the CDS channel switches in it because it
was full of 5532's and even with added fans, their life in that heat was
about a year, with a 24 input Macky(SP?). Digital, programmable motorized
gain pots, very low noise. But we had to shut the studio monitors off, the
delay had our talent stumbling over their own shoelaces trying to read the
teleprompter.
I didn't have a way to measure it, other than a dual trace scope and hand
claps which said 16 to 17 ms, but I'd have guessed around 20.
How long a delay is there between an organ note and the return echo in a
large cathedral? Much more than the millisecond scale, maybe?
Ages ago, we were at a Day on the Green concert in Oakland Coliseum, a
baseball field in California. Featured 5 big name rock bands. Stage was
set up around and behind home plate. We were on sitting on the grass of
the field, behind us was the 2-3 tiers of concrete seating.
One of the bands that was playing was Heart; at the time, a key element
of their sound was how clean it was. They were the 4th band to play.
They got up and played, and their sound was awful because of the
enormous echo coming off the concrete behind us. It was almost as loud
as they were, but heavily delayed. They went through their show and were
probably relieved. The first three bands were just straight loud rock
bands, they probably didn't even notice the echo, or thought it was cool
because it made things louder. Heart was followed by The Eagles (this
was part of their Hotel California tour) with Joe Walsh at the time.
They very skillfully integrated the echo into their performance, timing
things so the echo sounded like it was part of the music.
Knowing what
to expect, I still couldn't read the opening paragraph of a tv technology
article without stumbling lots of times if the monitor was loud enough to
sound like an echo. The TD can still talk in their ear, but no backfeed
goes out that circuit, its killed when the mics go live.
Hmm, I've never tried reading on TV. Worked on-air in a radio station,
but that was all headphones, and much smaller physical spaces.
We have an even newer board now, 48 stereo wide SMPTE out, and I believe
its considerable faster than the Macky was, but I don't think the studio
monitors are used for anything but talkback during commercials yet. I've
been retired since mid 2002, and haven't really tracked that stuff 100%
since.
Good to leave the work life behind and put your energy into your own
life! I transitioned from IT/IS work through systems analyst/business
analyst to what I do now, which is manage content and work with
enterprise content management systems from the business side. Since we
dropped using Windows in our house about 10 years ago, I'm way behind on
a lot of Windows things!
--
David W. Jones
gnome@xxxxxxxxxxxxx
authenticity, honesty, community
http://dancingtreefrog.com
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