Digidesign Sync IO cable question

Archived from groups: rec.audio.pro (More info?)

In article <020220050028337227%jtREMOVETHIS@tydirium.net> jtREMOVETHIS@tydirium.net writes:

> Is there a cable length limit on the BNC cables that connect to the
> Word Clock and/or video blackburst inputs on a Sync IO (or, for that
> matter, any other sync device)?
>
> I may be doing a gig where I have some potential long cable runs
> (hundreds of feet).

Video studios wire black burst through the building, and yes, they
usually use a video distribution amplifier for this.

> Also, if I have multiple devices requiring word clock from the master,
> is it better to daisy chain the word clock ins/outs, or to get some
> sort of distribution hub device, and send the clock to them all in
> paralell?

Send each one its own word clock. Daisy-chaining is an invitation to
clock problems when audio is interconnected.



--
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Archived from groups: rec.audio.pro (More info?)

In article <020220051050327455%jtREMOVETHIS@tydirium.net> jtREMOVETHIS@tydirium.net writes:

> So any idea at what length the DA becomes needed?

Generally a distribution amplifier has multiple outputs so you can
send one source to several destinations without worrying about
terminating impedances. Generally long runs go out separate outputs to
each room, and things are daisy-chained within a rack. You can usuall
make that work with video gear because it's designed with the idea in
mind that that you might actually have more than one piece in a system
that needs to be synchronized - most units that have facilities for
video syn have both an input and output connector and a termination
switch. Of course you have to be smart enough to know to terminate
only the end of the chain.

As far as how long you can run without using an amplifier, well that
depends on the source (voltage), the destination (sensitivity), and
the type of cable, as well as the length. In other words, you can run
as long a cable as you can get away with that gets you enough signal
to synchronize what's at the end of the cable. With pretty normal
stuff, I'd say you'd be safe with a 50 foot run. Beyond that, I'd
probably want to drive the cable with something I know is designed for
the purpose of driving a long cable.


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

Archived from groups: rec.audio.pro (More info?)

Cool.

I'll go with a rule of thumb that over 50 feet needs a DA and work from
there.

thanks for the tips.

JT




n article <cts5k2$a2c$1@panix2.panix.com>, Scott Dorsey
<kludge@panix.com> wrote:

> In article <znr1107365218k@trad>, Mike Rivers <mrivers@d-and-d.com> wrote:
> >
> >As far as how long you can run without using an amplifier, well that
> >depends on the source (voltage), the destination (sensitivity), and
> >the type of cable, as well as the length. In other words, you can run
> >as long a cable as you can get away with that gets you enough signal
> >to synchronize what's at the end of the cable. With pretty normal
> >stuff, I'd say you'd be safe with a 50 foot run. Beyond that, I'd
> >probably want to drive the cable with something I know is designed for
> >the purpose of driving a long cable.
>
> How far you can run basically depends on what cable you are using and
> how much clock error you're willing to tolerate at the other end. Fifty
> feet is no problem, but come a couple thousand feet and you're into
> the range of starting to worry about jitter problems even with good
> foamcore cable.
> --scott