Topic: Word clock question...

[Genghis Cougar Mellen Khan]

Theoretical question:

You have a unit that is suppose to be bit-accurate and another that can accept a WC, if you're sending one unit the digital out from a V3 and the other linked to the WC out, the 2 sources should share the same identical clock? 

I guess what I'm wondering is... is the timecode information inherently part of the data stream or does it go beyond that? 

I would like to be able to run 4 channels and not have to deal with sync issues in post, not really interested in an R4 at the moment.

[Brian Skalinder]

You have a unit that is suppose to be bit-accurate and another that can accept a WC, if you're sending one unit the digital out from a V3 and the other linked to the WC out, the 2 sources should share the same identical clock?

That's my understanding.  My ultimate 4-ch goal is a V3 + bit-bucket + 722.  Some day.

Hopefully someone with more knowledge and first-hand experience on this one will chime in.

[Genghis Cougar Mellen Khan]

You have a unit that is suppose to be bit-accurate and another that can accept a WC, if you're sending one unit the digital out from a V3 and the other linked to the WC out, the 2 sources should share the same identical clock?

That's my understanding.  My ultimate 4-ch goal is a V3 + bit-bucket + 722.  Some day.

Hopefully someone with more knowledge and first-hand experience on this one will chime in.

I was thinking of some possibilities...

Getting the ACM mod for my 671 and picking up a stock HD-P2 for the 2nd set of channels.

or

Getting a 722 and leaving my 671 stock and use it as the bit bucket.

[Brian Skalinder]

Getting the ACM mod for my 671 and picking up a stock HD-P2 for the 2nd set of channels.

I see a WC input on the HD-P2, but not an in or out on the 671...not sure how you'd sync the two.  Am I missing something?  Or are you looking at V3 > 671 and V3 WC-out > HD-P2?

Forgot about the P2, I could use that instead of the 722 for a significant chunk less cash.

[Genghis Cougar Mellen Khan]

I see a WC input on the HD-P2, but not an in or out on the 671...not sure how you'd sync the two.  Am I missing something?  Or are you looking at V3 > 671 and V3 WC-out > HD-P2?

I was thinking:

You're correct, the 671 has no WC input, I'd be using the V3 as the master clock (WC to the P2) and the 671 as a bit-bucket.

[BC]

Or are you looking at V3 > 671 and V3 WC-out > HD-P2?

Does that mean you would need to run WC and analog outs from the V3 to P2?

[Brian Skalinder]

Or are you looking at V3 > 671 and V3 WC-out > HD-P2?

Does that mean you would need to run WC and analog outs from the V3 to P2?

For 4-ch, I'd expect to run it like so:

Mics1-2 > V3 > digi-out > bit-bucket
Mics3-4 > HD-P2 + V3 > WC out > HD-P2

[Brian Skalinder]

in the above setup you end up with two separate, two channel recordings that are both synced to the same clock?  then one can blend mics 1/2 with mics 3/4 to taste in post easily and effortlessly since there is no need to sync?

Basically, yes.  There may be need for an initial sync, though.  For example, if one set of mics is on-stage and the other in the AUD, one set of mics will have a delay relative to the other.  Or if 2-ch are AUD and 2-ch are SBD, the AUD mics may have a delay relative to the SBD.  But after performing the initial sync, no further syncing is required because there's no clock drift.  So - align once, and done.  No re-aligning every 2-3-5-however many minutes as the clocks drift.

[TNJazz]

Theoretical question:

You have a unit that is suppose to be bit-accurate and another that can accept a WC, if you're sending one unit the digital out from a V3 and the other linked to the WC out, the 2 sources should share the same identical clock? 

I guess what I'm wondering is... is the timecode information inherently part of the data stream or does it go beyond that? 

I would like to be able to run 4 channels and not have to deal with sync issues in post, not really interested in an R4 at the moment.

In theory, yes they share the same clock.

Unfortunately, the two sources may still not line up properly in post.  There must be other reasons for sync drift.

I know because I tried this recently with my Rosendahl providing clock to 5 different devices (24 ch multitrack and a 4 channel aud/sbd backup).  The clock signal was sent to 3 digital preamps and my Alesis HD24 for the multitrack, and also to a Metric Halo for the 4 channel backup.  In post, I was unable to align the 24 channel mix with the 4 channel backup, even though ALL common clock was generated by the Rosendahl.

You may get lucky; you may not.  I have not tried since then but I will probably do something similar at the next gig I have because this thread has piqued my curiosity again.

Dirk

[Roving Sign]

My experiment using the same clock on two A/Ds also failed...(however there was digi-noise in one recording (cell phone -- I assume))  - not sure if that could have affected the post-sync...

Is it possible the recording device is "re-clocking" the signal as it comes in?

I know high-end audio guys always talk about "re-clocking" - - is there such a thing?

[JasonSobel]

Is it possible the recording device is "re-clocking" the signal as it comes in?

I know high-end audio guys always talk about "re-clocking" - - is there such a thing?

yes, there is such a thing as "re-clocking" and that could be what is going on in both of the examples above.

with the Tascam HD-P2 (for example), there are menu options to specify the audio source (mic in, line in, or S/PDIF), and you also need to specify the clock source (internal, S/PDIF, or Word Clock)... to continue this example, if you send the HD-P2 a S/PDIF signal, but have the clock source set to internal, it'll re-clock the incoming data based on it's internal clock.  so, if using the HD-P2 to sync up with another A/D, it's important to choose the WC option for the clock source.

in both examples above, the actual gear used wasn't specified, so it's hard to know exactly why their was drift between the sources.  if the two recordings were using the same clock, that wouldn't have happened, so my suspicion is that some of the recording gear was re-clocking the signal...

[TNJazz]

if the two recordings were using the same clock, that wouldn't have happened, so my suspicion is that some of the recording gear was re-clocking the signal...

It did happen, unfortunately.  My setup was as follows:

3x digital preamps (Focusrite, Ramsa and Mackie Onyx) all slaved to word clock input
all running ADAT to an Alesis HD24, ALSO slaved to word clock input
plus
Metric Halo 2882 ALSO slaved to word clock input going to a Powerbook G4 via firewire (4ch backup)

All 5 clocked devices were sent clock signal from the Rosendahl (which has 12 WC outputs, so it's not a daisy chain or distribution amp thing)

[Roving Sign]

My set up used a dbx386 (pre/a>d combo) as the master clock...dbx clock out to a Behringer Ultramatch A/D - (via BNC)

The 386 used a CO2 to convert coax to fiber and fed a JB3

The Behringer has optical out - feeding a second JB3

Pretty sure I had all the switches in the proper place...

I was going to do some cassette transfers later today - maybe I'll set up this stuff again - give it another shot...

[terrapinj]

You have a unit that is suppose to be bit-accurate and another that can accept a WC, if you're sending one unit the digital out from a V3 and the other linked to the WC out, the 2 sources should share the same identical clock?

That's my understanding.  My ultimate 4-ch goal is a V3 + bit-bucket + 722.  Some day.

Hopefully someone with more knowledge and first-hand experience on this one will chime in.

why not 744 + pre? seems you'd be close to the same $ by time you figure in the v3 and bit bucket and would be much easier and smaller to run

[ethan]

I've got two working AD1K's now and am planning on doing some 4 channel stuff by syncing them.

-e

[Brian Skalinder]

why not 744 + pre? seems you'd be close to the same $ by time you figure in the v3 and bit bucket and would be much easier and smaller to run

Partly for flexibility's sake - I sometimes prefer the straight V3 pre/ADC sound - but mainly price.  While definitely easier with the 744, it's about a grand more.  If I can come up with the scratch, I'll probably go that route eventually:

$4,000 | 744
$  750 | Preamp of choice (used)
=================================
$4,750

$2,400 | 722
$1,100 | V3 (used)
$  330 | MT2496
$   70 | CF media
=================================
$3,900

[terrapinj]

for some reason i was figuring in the p2 as your bit bucket, not sure where that idea came from though 

im gonna be borrowing Ian's 722 this weekend to sync up the two AUD + SBD - while definitely the most expensive option im curious to see how the C. Link function works

[thegreatgumbino]

why not 744 + pre? seems you'd be close to the same $ by time you figure in the v3 and bit bucket and would be much easier and smaller to run

Partly for flexibility's sake - I sometimes prefer the straight V3 pre/ADC sound - but mainly price.  While definitely easier with the 744, it's about a grand more.  If I can come up with the scratch, I'll probably go that route eventually:

$4,000 | 744
$  750 | Preamp of choice (used)
=================================
$4,750

$2,400 | 722
$1,100 | V3 (used)
$  330 | MT2496
$   70 | CF media
=================================
$3,900

Scenario 3:
722 = $2,400
V3 (used) = $1,100
iRiver H120 or JB3 = $150
Total = $3,650

Going with scenario 3 obviously doesn't allow you to record both sources in 24bit, but it would be $350 less than the 744 alone.

I've been thinking about this lately, and it seems to me you could run SBD > iRiver H120/H140 (analog in) > optical out > Hosa box > spdif in > 722.  This would clock the 722 to the iRiver clock and cut out the V3 or P2 wordclock since you can slave the 722 to a separate digital signal while recording.  This would be more parts & pieces but would save you about $1,400 compared to the 744.

[Brian Skalinder]

Going with scenario 3 obviously doesn't allow you to record both sources in 24bit, but it would be $350 less than the 744 alone.

Actually, $250 less.  (3900-3650=250)  That $250 is well worth it to get to 24-bit, IMO.

[thegreatgumbino]

Going with scenario 3 obviously doesn't allow you to record both sources in 24bit, but it would be $350 less than the 744 alone.

Actually, $250 less.  (3900-3650=250)  That $250 is well worth it to get to 24-bit, IMO.

ACTUALLY, You used $4,000 for the price off the 744.  Therefore, $4,000-$3,650=$350.   

$4,000 | 744

I think you're probably right though.  When you have that much money in your rig, what's another $350 to go full 24 bit?  The only problem I see there is that the MT is the only 24 bit capture device that I can think of for that cheap, and I don't know if I trust it.  I think I'd rather stick to the iRiver or JB3 and save my pennies until another option comes up.

edit: On the other hand, if you don't record 4 mic or 2 mic + SBD sources often is the additional cost worth it?

[Brian Skalinder]

ACTUALLY, You used $4,000 for the price off the 744.  Therefore, $4,000-$3,650=$350.   

Duh...I missed the 744 alone part.  I figured it made more sense to compare your scenario to the 722 scenario.  Shall we recalculate all scenarios  in base 8?

I think you're probably right though.  When you have that much money in your rig, what's another $350 to go full 24 bit?  The only problem I see there is that the MT is the only 24 bit capture device that I can think of for that cheap, and I don't know if I trust it.  I think I'd rather stick to the iRiver or JB3 and save my pennies until another option comes up.

Exactly...what's another $250, or $350, depending on the scenario, to get from 2-ch 16-bit + 2-ch 24-bit to all 4-ch 24-bit.  On the other hand, a difference of $1k on two different 4-ch 24-bit solutions (my original two scenarios) is a bigger deal to me personally.  I have no problem relying on the MT2496 - did it for a while, and I'd be comfortable doing it again.

[TNJazz]

Just buy an R4 and shut the hell up everyone...   

[Shawn]

what about just using two hdp2 units. They can be had for $800 new on ebay.


Scenario 4
$800   | hdp2 (new off ebay)
$800   | hdp2 (new off ebay)
$1,100 | V3 (used)
$1,100 | V3 (used)
=================================
$3,800


That gets you 4 channels of V3 pre/ad, 24/192 capabilites, word clock syncability. all for less than either scenario involving a 7xx box.

[thegreatgumbino]

what about just using two hdp2 units. They can be had for $800 new on ebay.


Scenario 4
$800   | hdp2 (new off ebay)
$800   | hdp2 (new off ebay)
$1,100 | V3 (used)
$1,100 | V3 (used)
=================================
$3,800


That gets you 4 channels of V3 pre/ad, 24/192 capabilites, word clock syncability. all for less than either scenario involving a 7xx box.

Definitely do-able, but it seems like a heck of a lot to schlep around.  Additionally, don't you have to account for CF cards for both of the P2's?  If so, add another couple hundred.

I still like the 722 option though since you can run it as a stand alone all in one box if desired.

[Shawn]

what about just using two hdp2 units. They can be had for $800 new on ebay.


Scenario 4
$800   | hdp2 (new off ebay)
$800   | hdp2 (new off ebay)
$1,100 | V3 (used)
$1,100 | V3 (used)
=================================
$3,800


That gets you 4 channels of V3 pre/ad, 24/192 capabilites, word clock syncability. all for less than either scenario involving a 7xx box.

Definitely do-able, but it seems like a heck of a lot to schlep around.  Additionally, don't you have to account for CF cards for both of the P2's?  If so, add another couple hundred.

I still like the 722 option though since you can run it as a stand alone all in one box if desired.

yeah it would be a hell of a lot to lug around. I forgot CF memory. that would a few hundred more. maybe bring the total up to around $4000.

You can run the hdp2 stand alone if you wanted to carry a light rig. hell... if you wanted you could just bring both p2s and still have 4 channel word clockable 24 bit capabilites. that would be comparable to 744 + pre.

[thegreatgumbino]

yeah it would be a hell of a lot to lug around. I forgot CF memory. that would a few hundred more. maybe bring the total up to around $4000.

You can run the hdp2 stand alone if you wanted to carry a light rig. hell... if you wanted you could just bring both p2s and still have 4 channel word clockable 24 bit capabilites. that would be comparable to 744 + pre.

I agree, but the 722 is smaller than the HDP2, has a better build quality, and sounds better IMO.  Not to mention SD's customer service is top notch.  Just personal preference. 

Definitely a good point though.  For that matter, someone could run two Oade mod P2's & word clock them for a great sounding rig that is about the price of the 722 alone.

Edit:  The P2 doesn't have word clock out, only clock in, so I don't think it's do-able to sync two P2's.

[TNJazz]

yeah it would be a hell of a lot to lug around. I forgot CF memory. that would a few hundred more. maybe bring the total up to around $4000.

You can run the hdp2 stand alone if you wanted to carry a light rig. hell... if you wanted you could just bring both p2s and still have 4 channel word clockable 24 bit capabilites. that would be comparable to 744 + pre.

I agree, but the 722 is smaller than the HDP2, has a better build quality, and sounds better IMO.  Not to mention SD's customer service is top notch.  Just personal preference. 

Definitely a good point though.  For that matter, someone could run two Oade mod P2's & word clock them for a great sounding rig that is about the price of the 722 alone.

Edit:  The P2 doesn't have word clock out, only clock in, so I don't think it's do-able to sync two P2's.

Clock signal is inherent in any digital stream.  You could clock them together via SPDIF.  Can you record analog in if the clock is set to SPDIF though, that's the question.

[pilgrims622]

im curious to see how the C. Link function works

make sure both 7xx series units are on the same version, are set to same bit/khz rate, set to same preroll time and it should work great

[terrapinj]

im curious to see how the C. Link function works

make sure both 7xx series units are on the same version, are set to same bit/khz rate, set to same preroll time and it should work great

sweet, thanks! not sure if they are on the same firmware, definitely have to check that one out

[thepassionofyonder]

edit: On the other hand, if you don't record 4 mic or 2 mic + SBD sources often is the additional cost worth it?

im presently looking into going to 24 bit and im not sure which damn direction to go.
this thread is answering a bunch of the questions im having.
but im still trying to justify spending more money on this hobby,
and how much more i can justify spending without going overboard for my needs.

[JasonSobel]

Clock signal is inherent in any digital stream.  You could clock them together via SPDIF.  Can you record analog in if the clock is set to SPDIF though, that's the question.

on the HD-P2, the clock source is set independently of the signal source.  so, although I have never tried it, I'm pretty sure that you can record via mic-in or line-in, and set the clock to S/PDIF.  so that you send an S/PDIF signal from one HD-P2 to the other, and the one you are sending it to only uses it as a clock source and ignores the audio data.  pretty clever...