Mackie d8b/DIO-8 lightpipe to MOTU 2408 (and MOTU Traveler)

[smallisland]

Thanks for any help with this...

For a very long time, I have had intermittent issues using my 2408 Mk1/PCI-424 to transfer 24 channels of digital audio via lightpipe from a Mackie d8b (with 3 x DIO-8 cards) to my Mac DAW (more recently using Logic 9 or Digital Performer 6). I think I have word clock sync configured correctly (d8b as master using an Apogee Card), and the system can be quite stable for a while... BUT THEN, for no apparent reason, it can become a monster ... pops, crackles, thumps etc.

I am not looking for a cure all... (a reset of the system normally relieve the ills for a while.) HOWEVER I would like some specific feedback about one potential issue from anyone who might have this, or a similar set up.

I have just read on the Mackie forum that the DIO-8 cards for the Mackie d8b have had 3 revisions to their EPROMs (see below)... as follows:


• Version 1 (M-108C, V 1.01) –16-bit only, SYNC output is in phase with the word clock (incorrect according to the TASCAM standard).

• Version 2 (Version 2, 127 Ver 2) – 24-bit throughput, SYNC output phase with respect to word clock is still incorrect.

• Version 2.1 (Ver 2.1) – 24-bit throughput, SYNC output phase corrected to work properly with the older DTRS recorders.

THEN THERE IS THIS SNIPPET OF INFORMATION IN THE FORUM AND DATABASE THAT GOT ME THINKING AND A LITTLE CONCERNED:

" Always use version 2.1 EPROM (see the socketed chip on the DIO-8 card) with 24 bit TDIF devices (DA78HR's, DA98HR's, RADAR & MOTU2408). All versions of DIO-8 will function with older Tascam DTRS recorders (DA38's, DA88's & DA98's). The TDIF interfaces on these devices require the clock signal from the DIO-8 card's BNC sync output, with the exception of the MX2424 - which can also be clocked from the Word Clock output of the Apogee Clock I/O card.
Note: When connecting DIO-8 cards together, be sure they are all running the same EPROM version."


I happen to have 3 x DIO-8 with the Version 2, 127 EPROM... BUT I AM NOT USING TDIF OR ANY TASCAM DEVICES, just the ADAT Lightpipe to transfer audio via the 2408 directly to the DAW.

Could someone please tell me if it is necessary for me to update the EPROMS to 2.1 ONLY when using TDIF and/or Tascam equipment with the MOTU 2408... or if indeed I must do the same in order to use Lightpipe correctly. (Unfortunately the EPROMS are now almost impossible to find so "upgrading" would require buying newer second-hand DIO-8 or OPT-8 cards. (Of course, I'd prefer not to do this... but would if it was a guarantee of properly operating system)

Also... would the same information apply to using a MOTU Traveler Mk 1 over lightpipe, as well.

Thank you again for any help on this. I truly appreciate it!!!!!

[FrankH]

You shouldn't have any problem with the DIO cards you have as far as any lightpipe issues are concerned (other than simply flipping the polarity of the tape returns to maintain phase coherency between inputs and returns from the DAW).

I still have four V2 DIOs and never had a sync problem with them between an RME HDSP 5296 or MOTU 2408mk3 and the various Macs I've had running Cubase 6, Logic 9 or Studio One.

It could be a 2408mk1 driver issue. There is an update for that on MOTUs site. You don't say if you're having the same problem with the Traveler. Same problem there? You're obviously using a Mac. What OS are you running? I don't think an OS beyond 10.6 should be an issue...but it'd be good to know.

Presently, I'm using 3 OPT8 cards to the 2408mk3 and I have no syncing issues to the Mac. But I do something a bit different. I use an old Symetrix GenX192 master clock to act as master clock...feeding both the D8B and MOTU 2408.

However, it's your description of the intermittent clicks and pops that prompts this question: Are you using and "Aggregate Devices" in your Mac? A combo of, lets' say, the 2408 and built-in or the 2408 and the Traveler or any combination at all? The reason I ask is that I have encountered what you describe when using an Aggregate occasionally. And that always requires opening up the AudioMIDI control pane and resetting one of the units forming the aggregate device to be the master clock between the two (or three) aggregate devices.

Could that be the case?

[smallisland]

Hi Frank,

Really appreciate your help!

Just so you know, I am a long-time video/multimedia production guy (ex-musician/wanna do it again sometime for fun!!) who now sees making music more as a creative hobby than a profession. The problem is, when I have a very occasional chance to sit down and get musically creative it often feels like I spend most of that time hassling with software/equipment... and reading forums!


I bought the d8b for video soundtrack work when it first came out - using the MOTU 2048 with a PCI-324 Card to a Nubus Mac and Digital Performer. Brilliant. Then went to MOTU PCIX-424 when Mac was updated, but started getting the popping issues, and found the PCI-x card slowed down the e-Sata cards running our video raids, so moved to the MOTU Traveller for all inputs/outputs to our system and only used the Mackie for "live" studio fun!!.

Today my system is MacPro 8-core, 14 Gigs RAM, OSX 10.6.8. Internal 3 x 2TB (6TB) RAID 0, AJA Kona 3 HD Video Card, etc. ... but still have the Mackie begging to be used. As I am just starting to set up "play dates" with some musician friends of mine, I thought I would upgrade my PCI card to PCI-e and get the D8b and 2408 back into the mix for ease of set up for "practice" and getting 24 channels into (and possibly out of) the DAW if we actually come up with something reasonable to record . I know, the Mackie converters may not be the best, resolution is only 48K, etc. but that's fine. I do have a Liquid Channel if and when I want to input something really nice into the system.

So that's where I am right now... getting ready to try it all out again. The Traveller has been pretty stable with the d8b but I'd really like to have more I/Os and don't want to upgrade to a new mixer, AD converters (or purchase a Big Ben) if I don't have to (wife's rules!!!!). Having said that it would be nice to have the d8b, MOTU 2408, Liquid Channel and Traveller hooked up at the same time to the Mac. I also have a Korg Oasys that could be digitally connected to the system in stereo via SPDIF if it can all be synced (I don't have the ADAT card for OASYS).

Trouble is, I have to admit, that even though I feel I am reasonably experienced, all the information and opinions that are out there can be exhausting in deciding what will or won't work... and certain things do have me baffled.

For example, the "flipping of the polarity of the tape returns to maintain phase coherency between inputs and outputs and returns from the DAW" - I know I should probably know what that means/does to the system, and how it can be accomplished... but I have to come clean and say that, without more reading, I really don't! And will that cause issues going directly into, for example, Logic (and monitoring from Logic), rather than returning signal back to the d8b and monitoring from the d8b? Could that be the reason for my recent tests/perceptions that the audio I get can sometimes be quite "thin" and "harsh" when going 8 channels of ADAT from the d8b via the Traveller (and would EPROM 2.1 solve this?)

I'm happy to do more reading, but if you can enlighten me, I would truly appreciate it.

Same goes with Aggregating Devices. Haven't ever done that to my knowledge. If you could give me a little insight, i will be a great student and follow up with homework.

Frank (and anyone else)... I really thank you for your time.

Best regards,
David

[FrankH]

The polarity issue is an odd one. This is what's happening: as you make your recording through the DIO8 card, the lightpipe sends the signal out to your DAW 180° out of phase. This in itself is not life threatening...particularly if all of your recording and playback were to be done exclusively through the D8B.

However, there are some aficionados who strongly believe that playing back a polarity (or phase) reversed version of the original recording doesn't sound the same as it did going in...because the positive portion of the initial note attacks will be pulling the speaker in rather than pushing it out. While the science part of that is true, the practicality of the perception of it is debatable. Listen back to a stereo mix of something and flip the phase switch on both channels a few times and see if you can tell the diff. I can't.

However, if you were to flip the phase of one of the channels of that mix...then....you'd hear the difference. Trust me...it won't be subtle.

But, as a purist, I am of the belief that phase coherency should be maintained throughout the entire recording chain. It's just good practice. When I had the DIO8s installed, I always kept the tape returns flipped. I don't have to do that with the OPT8s.

As to the "thin or harsh" comment...it sounds like you may be "double monitoring" somewhere....where you are hearing the input being monitored (in phase) along with the DAWs output (out of phase) at the same time. With a perfect phase reversal, you'd hear nothing: [+1]+[-1]=0. But because there is some inherent delay from the round trip of console to DAW back to console, it moves the two signals far enough out of time from each other that complete phase cancellation is impossible. But you will get some cancelling and that will usually present itself as a form of comb-filtering. Some frequencies are canceled (disappear) resulting in a thinner or possibly harsh result.

That said, it's hard to tell what you're doing without being there, so I'm just kind of guessing here. But that's what it sounds like is happening.

The solution is simple. Don't double monitor. Make sure the D8B's inputs are being routed only to the DAW and not to the 2mix at the same time while routing the DAW back to the D8Bs tape returns.

Addressing your original problem of intermittent pops and crackles. Clicks and pops are almost always exclusively a WordClock issue. Since you have an Apogee WordClock card installed in your D8B, I would suggest making sure that the integrity of the WC chain is maintained all the way from the D8B to the DAW and back via software checks.
And that the WC cable from D8B to 2408 or Traveler is of good quality.

This means that you need to make sure the MOTU Audio Setup control panel has External chosen as Clock Source and that Logic agrees with this choice. I have found that on occasion, the MOTU units sometimes revert to Internal Clock if they are powered on after the D8B. It needs to confirmed before every session.

I don't know about Logic or DP6 but I know for a fact that I have to double check Cubase 6's Device setup page to make sure it agrees with the idea that the 2408 is getting External clock. I've had a few recordings ruined because the MOTU setup showed External clocking but Cubase had chosen Internal because I powered the Mac up before the MOTU unit. Yes...power-up sequence makes a difference. There are some threads on this in this forum. MIne happens to be MOTU, GenX, D8B and finally the Mac. YMMV and only a bit of trial and error will determine the best sequence for you.

But I did say: almost exclusively. There is a possibility that your DAWs initial I/O buffer size may be set too low and you are overtaxing the CPU.

Nearing the end: Aggregate devices.

This is a Mac OS thing. There is a + button on the lower left of the Mac AudioMIDI setup. It is designed to create an "aggregate device" to let you combine a few audio I/O sources (like for example, the 2408 via lightpipe and Traveler via FW) so that it is seen by your DAW as a single device. Rather than me explaining it, open the panel and click the purple ? for a detailed explanation of the features.

Suffice to say, the Aggregate's resyncing and master clock selections make the difference between it working properly or not.

Finally: no, you don't need to spend money on V2.1 DIO8 cards. Not at all. The only advice I would make concerning a wife-approved purchase would be for a Master Clock. And not necessarily the rather overpriced Big Ben. See if you can find a used Symetrix GenX192 for cheap out there. It out-specs the Big Ben. Whatever you find, the idea is to get it to feed WC to the D8B, 2408 and Traveler. I only make this suggestion because I have found that using a better Master Clock instead of the Apogee card's clock to drive my D8B, 2408 and HDR cut WC issues down to nothing. Depending on well you fare with your setup, you may never need a master WC at all. Personally, I like to hedge my bets.

[smallisland]

Frank,

You have been so very generous with your time and expertise.

I will get to setting up the system with renewed vigor and direction.

Thank you so much.

Best regards,

David