[Steve[_3_]]

Hi all;

During the last few songs I have been tracking I have been running into sync
problems. Here are the devices I use:

Interface - Tascam FW-1804
Focusrite Twintrak Pro - SPDIF -- FW-1804
Behringer ADA-8000 - ADAT -- FW1804

These problems seem to come and go. The 1804 seems to have a clock source
hirerachy to sync properly. If you are using ADAT and SPDIF you have to use
ADAT as the clock source. If you aren't using ADAT then the SPDIF has to be
clock source, then internal. It would be nice to have all my external
devices set to the proper sample rate depending on the project I am tracking
and not have to mess around with flipping sample rate switches on the back
of my rack. Most of them are 48,000 but some source material is in 44,000
and rarely at 96,000. Both the Twintrak and ADA have a word clock in. I
usually playback through my Twintrak's SPDIF and DEQ2496 which also have
word clock ins.

My questions a
1. Will word clock achieve my goal outlined above?
2. What type of cable do I use (RG59, RG6?).
3. Do I need to terminate any or both ends of the wordclock segment, if so
what terminator do I use?
4. Is there a limit to the number of devices I can have connected?
5. Are there any additional benefits by controlling my equipment by
wordclock?

Thanks in advance for the help!
Steve

[Mike Rivers]

Steve wrote:

During the last few songs I have been tracking I have been running into sync
problems. Here are the devices I use:

Interface - Tascam FW-1804
Focusrite Twintrak Pro - SPDIF -- FW-1804
Behringer ADA-8000 - ADAT -- FW1804

First principle: Everything needs to see the same word clock.

Second principle: Daisy-chaining word clocks is something that you can
occasionally get away with, but it doesn't really work very well.

Third principle: If you have more than two digital audio devices
connected together, you really need to understand what you have and what
possibilities you have for synchronizing them. Some combinations are
impossible to do correctly due to a lack of the proper connections.

The 1804 seems to have a clock source
hirerachy to sync properly. If you are using ADAT and SPDIF you have to use
ADAT as the clock source. If you aren't using ADAT then the SPDIF has to be
clock source, then internal.

It's not a matter of priority. It apparently can be set to use either an
incoming S/PDIF or incoming ADAT optical data stream as the word clock
synchronization source. If you're feeding both S/PDIF and ADAT streams
to the 1804, then those two streams must be synchronized so that all
three devices are synchronized.

It would be nice to have all my external
devices set to the proper sample rate depending on the project

Not only would it be nice, it is necessary. The proper way to do this is
to only use devices with word clock inputs, set each device to use
external word clock, and feed all of the word clock inputs from the same
source - either an external word clock generator with multiple outputs
or by using one device's word clock output (this device will be running
on its internal clock) connected to the word clock inputs of the others.
But if you do this, you need to understand loading and terminations, and
again, lack of certain capabilities make make this impossible.

My questions a
1. Will word clock achieve my goal outlined above?

Yes.

2. What type of cable do I use (RG59, RG6?).

RG-59 (75 ohm), but for rack-length cables (less than 10 feet or so) you
can get away with almost any kind of coax. Best to use the right thing,
though.

3. Do I need to terminate any or both ends of the wordclock segment, if so
what terminator do I use?

Here's the rule. You need to terminate the end (and only the end) of a
chain. Some (most, actually) word clock inputs have a built-in
terminator, so you don't have to worry about using another part. But
most don't give you a choice of a terminated or unterminated input. If
you use a T adapter on Device 2's word clock input and then connect that
on to Device 3, you need Device 3 to be terminated and Device 2
unterminated. If nothing has an internal terminator (unusual) then you
need to put a T on the input, plug the word clock cable into one side of
the T and plug a 75 ohm terminator into the other side of the T. If both
devices have internal termination and no switch to unterminate the
input, then you can't feed both from the same source and rely on it
working.

4. Is there a limit to the number of devices I can have connected?

I'm sure there's a practical limit, but if you pay attention to
termination or feed each word clock input from its own (synchronized)
output, you can connect as many devices as you want in a system.

5. Are there any additional benefits by controlling my equipment by
wordclock?

Additional to working correctly? How much more can you expect? g

You'll find a brief writeup with some diagrams he
http://lib.store.yahoo.net/lib/yhst-.../clocksync.pdf



--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Steve[_3_]]

Thanks Mike. Got it all linked together today and it seems to be working
fine (all for about 15 bucks in parts...priceless). My Focusrite ADC card
has a terminator built in (it's selectable internally by jumper), but the
ADA8000 does not. I simply kept the Focusrite at the end of the chain.

In addition to everything being synced it sounds 100% better now. I am
hearing sounds I could never hear before! (kidding.....)

Cheers;
Steve

"Mike Rivers" wrote in message
news:K3Rtk.920$482.781@trnddc06...
Steve wrote:

During the last few songs I have been tracking I have been running into
sync problems. Here are the devices I use:

Interface - Tascam FW-1804
Focusrite Twintrak Pro - SPDIF -- FW-1804
Behringer ADA-8000 - ADAT -- FW1804

First principle: Everything needs to see the same word clock.

Second principle: Daisy-chaining word clocks is something that you can
occasionally get away with, but it doesn't really work very well.

Third principle: If you have more than two digital audio devices connected
together, you really need to understand what you have and what
possibilities you have for synchronizing them. Some combinations are
impossible to do correctly due to a lack of the proper connections.

The 1804 seems to have a clock source hirerachy to sync properly. If you
are using ADAT and SPDIF you have to use ADAT as the clock source. If
you aren't using ADAT then the SPDIF has to be clock source, then
internal.

It's not a matter of priority. It apparently can be set to use either an
incoming S/PDIF or incoming ADAT optical data stream as the word clock
synchronization source. If you're feeding both S/PDIF and ADAT streams to
the 1804, then those two streams must be synchronized so that all three
devices are synchronized.

It would be nice to have all my external
devices set to the proper sample rate depending on the project

Not only would it be nice, it is necessary. The proper way to do this is
to only use devices with word clock inputs, set each device to use
external word clock, and feed all of the word clock inputs from the same
source - either an external word clock generator with multiple outputs or
by using one device's word clock output (this device will be running on
its internal clock) connected to the word clock inputs of the others. But
if you do this, you need to understand loading and terminations, and
again, lack of certain capabilities make make this impossible.

My questions a
1. Will word clock achieve my goal outlined above?

Yes.

2. What type of cable do I use (RG59, RG6?).

RG-59 (75 ohm), but for rack-length cables (less than 10 feet or so) you
can get away with almost any kind of coax. Best to use the right thing,
though.

3. Do I need to terminate any or both ends of the wordclock segment, if
so what terminator do I use?

Here's the rule. You need to terminate the end (and only the end) of a
chain. Some (most, actually) word clock inputs have a built-in terminator,
so you don't have to worry about using another part. But most don't give
you a choice of a terminated or unterminated input. If you use a T adapter
on Device 2's word clock input and then connect that on to Device 3, you
need Device 3 to be terminated and Device 2 unterminated. If nothing has
an internal terminator (unusual) then you need to put a T on the input,
plug the word clock cable into one side of the T and plug a 75 ohm
terminator into the other side of the T. If both devices have internal
termination and no switch to unterminate the input, then you can't feed
both from the same source and rely on it working.

4. Is there a limit to the number of devices I can have connected?

I'm sure there's a practical limit, but if you pay attention to
termination or feed each word clock input from its own (synchronized)
output, you can connect as many devices as you want in a system.

5. Are there any additional benefits by controlling my equipment by
wordclock?

Additional to working correctly? How much more can you expect? g

You'll find a brief writeup with some diagrams he
http://lib.store.yahoo.net/lib/yhst-.../clocksync.pdf



--
If you e-mail me and it bounces, use your secret decoder ring and reach me
he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)

[Mike Rivers]

Steve wrote:
Thanks Mike. Got it all linked together today and it seems to be working
fine (all for about 15 bucks in parts...priceless).

Nothing like doing something right. Glad you got it sorted out.


--
If you e-mail me and it bounces, use your secret decoder ring and reach
me he
double-m-eleven-double-zero at yahoo -- I'm really Mike Rivers
)