Topic: Syncing a V3 Word Clock output with a DMIC-20 AES REF input

[Chuck]

This from Graham Patten today:

Charles,
 
The clock will be derived from the Ext sync, S/PDIF, input.  Only with no ext.
reference does the DMIC run on the internal 48KHz crystal.  The clock will be
locked to the ext. ref.
 
Where ever you send the output of the DMIC will need to be locked to the same
clock if you want everything sync'd to the same clock.
 
Mike

[Todd R]

Cool, looks like it'll work then.  Looking forward to hearing how your experiments go.

BTW, that last line looks like he is just saying you need to be recording off the DMic with a bit perfect recorder -- obviously can't use a recorder that re-samples in the digital input (like the R4?).

[gratefulphish]

This from Graham Patten today:

Charles,
 
The clock will be derived from the Ext sync, S/PDIF, input.  Only with no ext.
reference does the DMIC run on the internal 48KHz crystal.  The clock will be
locked to the ext. ref.
 
Where ever you send the output of the DMIC will need to be locked to the same
clock if you want everything sync'd to the same clock.
 
Mike

Apparently, I stand corrected, but I am still having trouble understanding why just about no other devices on the market offer this type of simplified wordclock synching.  The last sentence is also unclear.  Does that just mean a bit perfect deck, or a deck that also has a wordclock input?  While the R-4 resamples, the R-4 Pro does not.  In other words, having the V3 synched to the DMIC may be one thing, but having the decks to which the signals are going may be another.  That seems to be why they have these very expensive, multi-channel word clock generators.  Anyone?

[Chuck]

It's going to be a while until I'll be able to properly test all this out. I don't have the DMIC yet and I will have to add an optical output to it before I can record to the iRiver. I do have another iRiver on the way though. I figure I may as well replace the BNC connectors on the DMIC with RCA's as they are much easier to come by and work with.

Who'd have guessed I'd be a gear slut. My wife is going to kill me, and tonight being Valentines Day night and I'm going out to record Particle.    She did take that news well, I think.

[gratefulphish]

It's going to be a while until I'll be able to properly test all this out. I don't have the DMIC yet and I will have to add an optical output to it before I can record to the iRiver. I do have another iRiver on the way though. I figure I may as well replace the BNC connectors on the DMIC with RCA's as they are much easier to come by and work with.

Who'd have guessed I'd be a gear slut. My wife is going to kill me, and tonight being Valentines Day night and I'm going out to record Particle.    She did take that news well, I think.

You won't need to worry about the synching, if you are buried 6' under.  Go get some flowers.  Your testicles depend on it.

[Chuck]

It's going to be a while until I'll be able to properly test all this out. I don't have the DMIC yet and I will have to add an optical output to it before I can record to the iRiver. I do have another iRiver on the way though. I figure I may as well replace the BNC connectors on the DMIC with RCA's as they are much easier to come by and work with.

Who'd have guessed I'd be a gear slut. My wife is going to kill me, and tonight being Valentines Day night and I'm going out to record Particle.    She did take that news well, I think.

You won't need to worry about the synching, if you are buried 6' under.  Go get some flowers.  Your testicles depend on it.

Yeah, it's not as bad as all that, but thanks for the advice. 

[gratefulphish]

See my avatar.  Next to the switch for "Man" it just says "On/Off", the rest is self-explanatory.  Flowers go a long way, chocolate usually doesn't hurt either.

[Chuck]

I had not taken the time to check out that avatar. Yup you've got it right. 

[trajhip2000]

I wonder why resampling of two synced inputs would be a problem - if they are synced when they come in and then both are resampled by a recorder with its own clock, then they should end up synced at the recorder, no?

Stev

[Todd R]

Apparently, I stand corrected, but I am still having trouble understanding why just about no other devices on the market offer this type of simplified wordclock synching.  The last sentence is also unclear.  Does that just mean a bit perfect deck, or a deck that also has a wordclock input?  While the R-4 resamples, the R-4 Pro does not.  In other words, having the V3 synched to the DMIC may be one thing, but having the decks to which the signals are going may be another.  That seems to be why they have these very expensive, multi-channel word clock generators.  Anyone?

I'm pretty positive the last sentence just means you must make sure you're recorder doesn't screw up the syncing that the DMic will provide.  Which means that you must have a bit perfect recorder that does not re-sample on it's digital input.  Re-sampling on the digital input simply means it will use its internal clock, rather than the clock of the DMic (which has been locked to the clock from the AES ref).  They're not saying you'd need a wordclock in on your recorder, if that were the case, it wouldn't matter what clock the DMic was using.

As to why not more companies do it, who knows?  It takes some R&D to do, takes some circuitry to accomplish, and requires another connector on the outside of the box.  I guess most companies don't think it is worth it.

[Todd R]

I wonder why resampling of two synced inputs would be a problem - if they are synced when they come in and then both are resampled by a recorder with its own clock, then they should end up synced at the recorder, no?

Stev

You've lost me here, Steve.  Unless you use the same clock to resample the synced inputs, they will no longer be in sync.  What do you mean by synced when they come in and both resampled by a recorder?

[trajhip2000]

Sorry, I hadn't looked back at the beginning of the thread in a while, and was thinking that Chuck was talking about running into the R4, which does resample inputs (instead I see the R4 was mentioned by gratefulphish) - but since the R4 does that using the same clock on all 4 channels it shouldn't matter and they should still be in sync after resampling (I believe). But certainly if you are running into two diferent recorders and one or both of them resample and they aren't linked by wordclock then the two recordings will not be synced. But that does make me wonder - if you feed two digital sources that aren't synced into something like an R4 that does resample, then I guess they would end up synced?

Steve

[gratefulphish]

Sorry, I hadn't looked back at the beginning of the thread in a while, and was thinking that Chuck was talking about running into the R4, which does resample inputs (instead I see the R4 was mentioned by gratefulphish) - but since the R4 does that using the same clock on all 4 channels it shouldn't matter and they should still be in sync after resampling (I believe). But certainly if you are running into two diferent recorders and one or both of them resample and they aren't linked by wordclock then the two recordings will not be synced. But that does make me wonder - if you feed two digital sources that aren't synced into something like an R4 that does resample, then I guess they would end up synced?

Steve

Yes, I through the R-4 reference in.  But the R-4 only accepts two channels of digital input, same with the R-4 Pro.  The R-4 resamples, the R-4 Pro does not.  Since only two channels are digital on each machine, this discussion is somewhat academic as to them.  Chuck began this thread discussing using the DMIC and the V3 into different decks.  That is where the whole sync issue came up.  That is why I raised the issue of whether the decks themselves had to be synched by wordclock, and not just the pre/ADs.

[trajhip2000]

gotcha. Does the R4 Pro sync its internal clock to the incoming digital stream? if not, it would seem to me the R4 Pro has a significant disadvantage, since w/o resampling I don't see how the digital and analog sources will be in sync.

Steve

[Todd R]

Yeah, that sure is an interesting upshot to the R4 re-sampling.  Since it re-samples the digital input off its internal clock, you're right -- you should be able to feed it a digital signal, say from a V3, and then have 2 analog channels input, and then all 4 channels would be in sync.  Unless the R4 Pro has some way of accepting a wordclock in (don't have any idea if it does), then you wouldn't be able to sync an incoming digital signal with the analog channels.