Can I connect four DACs to the same source and expect them to play in phase?

[goldistan]

Application: LX512 speaker (4-way stereo crossover)
Source: miniDSP DDRC-88D
Potential DAC: four units of Topping E30 or SMSL 10th MKii

Will they work in phase? theoretically they should since clock comes from the SPDIF.
Other than measuring the speakers at the crossover point, how can I verify?

 

[dasdoing]

you need DACs that can be configured as master/slave, else they get out of sync. check the manuals. I guess you will need professional audio devices for that, but not sure

 

[dasdoing]

could be that the miniDSP will automaticly be master. I am realizing I can't realy help, other than the info that everything has to be in digital sync

 

[voodooless]

Since the DAC's will use SPDIF/AES they will just follow the DDRC. Should be no issue.

 

[tvrgeek]

I kind of doubt it as using 4 ports and the processor has to talk to each in turn. Plus, most "better" DACs have their own clock.
So, as mentioned, this puts you into the pro tools range.

What are you trying to achieve? You can buy multi-channel DACs from places like Sweetwater.

 

[voodooless]

I kind of doubt it as using 4 ports and the processor has to talk to each in turn.

What does that have to do with anything? There are all kinds of peripherals involved to mitigate these kinds of issues. It's not as if the CPU is bit-banging the SPDIF protocol times 4... And even it if would, it only needs 4 bits, so can actually be done at once, even an 8-bit CPU.

Plus, most "better" DACs have their own clock.
So, as mentioned, this puts you into the pro tools range.

With SPDIF the clock is encoded in the data, so the DAC derived that from it. If a DAC does ASRC, that is fine. It doesn't impact phase behaviour.

 

[dasdoing]

why use 4 DACs anyways? get a 8 channel interface

 

[tvrgeek]

Windows is not an RTA operating system. Might look at the protocol some more.

USB Operation: Protocol, Data Transfer & Packets » Electronics Notes

USB, Universal Serial Bus has a defined protocol for the data transfer using a variety of specific types of data packets for its operation.

www.electronics-notes.com

Our friend from Brazil has the most appropriate answer. Google "8 channel DAC" I think several folks have used the MiniDsp boards.
There are similar threads on this subject.

 

[voodooless]

Windows is not an RTA operating system. Might look at the protocol some more.

USB Operation: Protocol, Data Transfer & Packets » Electronics Notes

USB, Universal Serial Bus has a defined protocol for the data transfer using a variety of specific types of data packets for its operation.

www.electronics-notes.com

Windows was not brought up anywhere, so why bring it up at all? Neither has USB been brought to the table. Nor is having a real-time operating system relevant to the question. None of this is remotely relevant.

Our friend from Brazil has the most appropriate answer. Google "8 channel DAC" I think several folks have used the MiniDsp boards.
There are similar threads on this subject.

Nonsense, the proposed setup of the OP will work just fine.

 

[KMO]

In a simple SPDIF (or I2S) DAC, there's no way it can get significantly out of sync. If any DAC was able to get more than 1 sample away from any other DAC receiving the same signal, then the "slow" one would have to be buffering up data for later playback. And these devices do not have anything more than 1 or 2 sample's worth of buffer. So they have to output data as soon as they get it, they can't possibly introduce significant delay.

So maybe the DACs might be able to get of sync by a maximum of a few 10s of microseconds, equivalent to a fraction of a millimetre of distance.

If this was like an HDMI or USB input, you'd have more scope for getting out of sync, as there is a more complex data path. (Even aside from the fact that you wouldn't all be receiving one output link, which is what would really complicate that).

 

[Trell]

why use 4 DACs anyways? get a 8 channel interface

If the miniDSP DDRC-88D had ADAT he would have a much larger selection of (at least cheaper) 8 channel DACs (pro audio interfaces) than AES-EBU that miniDSP DDRC-88D can be configured with.

Personally I would look at pro audio with AES input for 8 channels and that would be a simpler setup as well.

 

[voodooless]

Personally I would look at pro audio with AES input for 8 channels and that would be a simpler setup as well.

How would that be a simpler setup? You'd need a PC handling the DSP processing and also need to buy a Dirac license for it as well.

 

[KSTR]

Will they work in phase? theoretically they should since clock comes from the SPDIF.

Yes.
Using multiple DACs this way is a completely viable solution and will work as expected, no need for specific checks.

 

[Juhazi]

I'm a happy user of Minidsp 4x10HD, and Tom Christiansen thinks it OK as well. As well recommended by late SL himself.

Review: MiniDSP 4x10HD

In-depth review and performance measurements of the MiniDSP 4x10HD.

neurochrome.com

Yes this lacks Dirac, but is it really needed? My guess is that user is capable of making room measurements and EQ settings "manually"
DDRC-88A with BM plug-in would be my choice if I wanted Dirac.

 

[KSTR]

@goldistan
But big gotcha: You already need 4 AES outputs on your host system and the XO must be done there. The miniDSP DDRC-88D does not buy you anything for splitting and XO... it would if it had multichannel USB input...

 

[Trell]

How would that be a simpler setup? You'd need a PC handling the DSP processing and also need to buy a Dirac license for it as well.

I was thinking of the miniDSP DDRC-88D digtal output to a DAC which he will need in any case: No need for extra DSP or Dirac license.

 

[voodooless]

I was thinking of the miniDSP DDRC-88D digtal output to a DAC which he will need in any case: No need for extra DSP or Dirac license.

Ah, but then one would need a device with ADAT and DIRAC... Good luck finding that (and not being a PC)!

 

[voodooless]

@goldistan
But big gotcha: You already need 4 AES outputs on your host system and the XO must be done there. The miniDSP DDRC-88D does not buy you anything for splitting and XO... it would if it had multichannel USB input...

What is this then: https://www.minidsp.com/products/dirac-series/ddrc-88bm

 

[KSTR]

What is this then: https://www.minidsp.com/products/dirac-series/ddrc-88bm

With this Plugin, yes, splitting and XO is possible.

 

[mansr]

Since the DAC's will use SPDIF/AES they will just follow the DDRC. Should be no issue.

It will be fine provided the DACs are identical. With different DACs, their latencies can vary, though the relative offsets will if course remain constant. Whether this is a problem depends on the application.