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RME User Forum → MADI/AES Premium Line → Clocking with MADI HDSPe and ADI-648
I'd appreciate a quick direction for clocking the MADI HDSPe, ADI-648 and on to several ADAT connected devices, i.e, ADi-8 DS, Apogee DA - 16x, Apogee AD - 16x, etc.
Does clock run from the MADI HDSPe to the ADI-648 via the MADI cable and then through the ADI-648 via ADAT out to the devices? Is that all there is to it?
Thanks.
It certainly can work that way if you configure everything that way. I use a combination of MADI/ADAT/BNC for clocking - as long as you configure everything properly there are numerous ways to get things sync'd.
I prefer to use my primary ADC as my system's master wordclock, and work back from there. I'm more partial to BNC Wordclock when possible, but some times it won't make any difference at all (true Digital-to-Digital transfers where AD/DA's aren't involved aren't affected by jitter at all unless severe enough to cause dropouts). RME's Steadyclock also negates a lot of these jitter related clocking concerns.
However, using your RME MADI card as your wordclock master will allow your DAW and/or RME Card to dictate the system's sample rate to your connected devices (S/MUX can get messy IIRC).
RME MADI + ADI-648 - What a flexible system 
Gotta love it!
Thanks!
It certainly can work that way if you configure everything that way. I use a combination of MADI/ADAT/BNC for clocking - as long as you configure everything properly there are numerous ways to get things sync'd.
My problem is I just know enough to be dangerous ... "can work that way" makes me kind of nervous.
I prefer to use my primary ADC as my system's master wordclock, and work back from there. I'm more partial to BNC Wordclock when possible, but some times it won't make any difference at all (true Digital-to-Digital transfers where AD/DA's aren't involved aren't affected by jitter at all unless severe enough to cause dropouts). RME's Steadyclock also negates a lot of these jitter related clocking concerns.
Uh, oh! I'm seeing some heavy BNC cable and T-connector purchasing here. I don't have a clear picture in my mind. Are you clocking the 1st ADC to the ADI 648 and MADI Card and then ADAT out from the ADI 648 to the other devices? Or? Somewhere between preferences and 'best practices' there are some things I need to learn. Your preference is because this makes the system less susceptible to jitter?
However, using your RME MADI card as your wordclock master will allow your DAW and/or RME Card to dictate the system's sample rate to your connected devices (S/MUX can get messy IIRC)..
If I plan to pretty much stick in the 44.1K world, would this be another plus for clocking from the MADI card? And in that case, would you recommend (similar to what I asked above) WC to the ADI 648 and ADAT from there to the ADCs and DACs?
Thanks!
My problem is I just know enough to be dangerous ... "can work that way" makes me kind of nervous.
I live there myself (being dangerous...) - and that's how I learn 
Or? Somewhere between preferences and 'best practices' there are some things I need to learn. Your preference is because this makes the system less susceptible to jitter?
Indeed - Somewhere in-between. The gear itself will dictate a lot of it, and then best practices and personal preference (to ward off the OCD! 
) go into an initial layout. Test the layout and see if it works reliably, and if the workflow meets your needs. Wash, rinse, repeat.
My main AD/DA converter is the system's wordclock master. Its BNC-OUT feeds the ADI648's BNC-IN with a Tee (unterminated), and then feeds the second AD/DA converter's BNC-IN (all using short 1-foot BNC cables). This second converter is terminated internally, so I decided to let that BNC chain end there.
Both converters feed the ADI648 over 12 ADAT I/Os (96 Channels worth).
ADI648 connects to MADIface-XT in my Primary DAW over MADI Optical (MADI port #1). I slave the MADIface-XT to this MADI input.
Then, the remaining 16 channels of ADAT I/O's on the ADI648 feed my V-Drum DAW with a Digiface. I'm only using the ADAT Outs from this V-Drum DAW (my DIY snake has 2x ADAT's, BNC and MIDI), so I slave the Digiface via BNC Coax from the ADI648's BNC-OUT (a re-clocked and buffered output).
Beyond that, I have a second VSTi DAW PC with an HDSPe MADI card connected to the MF-XT's MADI port #2 - This DAW is clocked over MADI Optical. "Steadyclock" cleans it up
Everything is solid while keeping my OCD tendencies in-check (mainly concerned about jitter with the main bank of AD/DA's, and that's covered as well as it can be).
If I plan to pretty much stick in the 44.1K world, would this be another plus for clocking from the MADI card? And in that case, would you recommend (similar to what I asked above) WC to the ADI 648 and ADAT from there to the ADCs and DACs?
I'm also a 44.1 guy. 88/96 is easily possible in my setup, but I'd have to change the way it's configured to get the most access to my analog I/O.
I'd say this is a reason to use your AD converter as your master. It's when you want the DAW to have control over the sample rate that it makes sense to let the DAW (your MADI Card) be the master. Since you stay @ 44.1K, you can let the AD converter be master and won't need to fiddle with changing rates manually at your converter.
I wouldn't sweat this too much - and don't waste cash on esoteric BNC cables and crap. Some descent Belden Video BNC cable is about all you'll need (if you even end up using BNC at all!).
Reliable rock-solid clocking is what you are ultimately after in the end. Set it and forget it. Make some music
Thanks again! Really appreciate your breaking down the routing ... but I want to be crystal clear I understand it.
Final points of clarification:
1) in your described setup, the MADI interface is slaved via MADI cables from the ADI648, yes?
2) the ADAT connected devices (other than the ADCs and DACs) are slaved via ADAT from the ADI648, yes?
Two other questions, if you please (revealing my deep ignorance).
1) Is there a way to take just two channels from an ADAT Toslink out to a XLR AES/ S/DIF in? I've been using a Dangerous Music Source for my monitoring control and that is its digital in, which I've been taking off a Multiface II S/PDIF. If I swap out to the MADI and ADI648 I need to figure out how to send a digital to the Source, which has its own DAC.
2) This is just a curiosity question ... W/C out source. Can it go either way out of a T-connector, or does it have to be at the beginning of a chain?
Thanks.
Thanks again! Really appreciate your breaking down the routing ... but I want to be crystal clear I understand it.
Yes sir. It can get hard to describe w/o a block diagram
Final points of clarification:
1) in your described setup, the MADI interface is slaved via MADI cables from the ADI648, yes?
Correct – My main interface is the MADIface-XT, and it is slaved to the incoming MADI Optical feed from the ADI648.
The slaved MADIface-XT also provides the clock to the 2nd DAW with the HDSPe MADI card over MADI Optical (which is still indirectly slaved to the Alphalink #1 in the end ).
2) the ADAT connected devices (other than the ADCs and DACs) are slaved via ADAT from the ADI648, yes?
The SSL Alphalink AD/DA’s are the primary ADAT Devices, and Alphalink #1 is Master, Alphalink #2 is slaved over BNC.
The Digiface (on the V-Drums PC) connects to the two remaining ADAT inputs on the ADI648, and this Digiface is clocked from the BNC Ouptut of the ADI-648 (a re-clocked and buffered version of the ADI648’s BNC Input in my setup). I terminate the BNC with a tee at the Digiface's BNC Input since it can not self-terminate internally.
If I was feeding the Digiface an ADAT Input from the ADI648 (which I'm not), it would gladly sync over ADAT (and being an all-digital box it's not affected by Jitter at all).
Two other questions, if you please (revealing my deep ignorance).
1) Is there a way to take just two channels from an ADAT Toslink out to a XLR AES/ S/DIF in? I've been using a Dangerous Music Source for my monitoring control and that is its digital in, which I've been taking off a Multiface II S/PDIF. If I swap out to the MADI and ADI648 I need to figure out how to send a digital to the Source, which has its own DAC.
Not without some kind of ADAT-to-SPDIF adaptor. The ADI-648 is a very flexible box, but does not offer any way to produce SPDIF or AES from MADI.
RME’s MADI-FX or MADIface-XT interfaces include an AES I/O and add TotalMix-FX (and has three MADI I/O’s!), so I might suggest you investigate upgrading from your HDSPe MADI card to one of those before dropping a ton of cash on a standalone ADAT-to-SPDIF converter box. The HDSPe PCIe MADI card is still holding its resale pretty well (unlike the PCI version), and then the price difference from selling your HDSPe MADI to a new MADI-FX will likely be cheaper than the cost of the SPDIF converter box IMO (or at least not much more).
2) This is just a curiosity question ... W/C out source. Can it go either way out of a T-connector, or does it have to be at the beginning of a chain?
Thanks.
Any WC Output feed should be the start of a chain (assuming the output is not just a “Loop Thru”, but an actual re-buffered output). Any “tees” should go on intermediary units, or as the final link of the chain with a terminator (if the last unit cannot terminate internally).
Randyman ...
A final thanks! You're help has been much appreciated.
As usual, Randyman's advice is both spot on and eminently practical. Make your primary ADC your clock master (either your ADI-8DS or your Apogee AD-16x) and pass that clock signal via word-clock onto your other ADC (checking that it is terminated correctly. This is often handled via a push-button or dip-switch; beware however, as some WC inputs are internally terminated by design with no switching option. This means that they must be at the end of a WC chain and can not be used in the middle of a WC chain via a T-connector). Your RME gear down the line from these ADC's will have no problem extracting the clocking information from the ADAT signals (or via word-clock if you prefer and your termination is correct). Randyman is also absolutely right about the BNC cables; grab some Belden or Canare 75 Ohm video cable and you're good to go. Word clock is a very simple clocking signal and good quality coaxial cable passes this on perfectly over large distances without a problem. As regards your Dangerous Source DAC requiring a SPDIF/AES signal, the Madiface XT looks like the perfect solution, as it will cover all of your interfacing needs. I am looking at one myself for similar reasons and for access to TotalMix-FX. Good luck and if you have any clocking issues get back to us. I also run mainly at 44.1 KHz and see no reason to jump to a higher sample rate, unless you are doing a lot of further processing down the line and therefore need the higher resolution to aid in further audio manipulation.
RME User Forum → MADI/AES Premium Line → Clocking with MADI HDSPe and ADI-648
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