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Using a 744T as an analogue to digital converter for a Motu Traveler


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The Motu Traveler has 8 analogue inputs and an additional 4 digital inputs SPDIF and AES. So I tried using my SD744T to provide 4 analogue to digital conversions to feed both the SPDIF and AES Motu digital inputs in an attempt to have 12 analogue inputs. To my suprise the 744T fed both the SPDIF and the AES inputs on the Motu successfully and it did not seem to matter whether the digital out setting on the 744T was set to domestic or professional, it still worked.

I ran a test with claps and zoomed in to the waveforms and was also suprised to see that there did not appear to be any delay on the digital ins (provided by the 744) alongside the analogue ins of the Motu.

So it seems to be possible to use a 744T as an AtoD box and get 12 analogue inputs to the Traveler without any delay problems.

I also connected the wordclock out of the 744T to the wordclock in of the Traveler but there was no discernable effect or indication that it made any difference. I fed one analogue in of the Motu with TOD timecode from the 744 and Boomrecorder successfully recognised and picked up the timecode.

Any reason why this setup might give problems, or any suggestions?

thanks

Mick

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The Motu Traveler has 8 analogue inputs and an additional 4 digital inputs SPDIF and AES. So I tried using my SD744T to provide 4 analogue to digital conversions to feed both the SPDIF and AES Motu digital inputs in an attempt to have 12 analogue inputs. To my suprise the 744T fed both the SPDIF and the AES inputs on the Motu successfully and it did not seem to matter whether the digital out setting on the 744T was set to domestic or professional, it still worked.

I ran a test with claps and zoomed in to the waveforms and was also suprised to see that there did not appear to be any delay on the digital ins (provided by the 744) alongside the analogue ins of the Motu.

So it seems to be possible to use a 744T as an AtoD box and get 12 analogue inputs to the Traveler without any delay problems.

I also connected the wordclock out of the 744T to the wordclock in of the Traveler but there was no discernable effect or indication that it made any difference. I fed one analogue in of the Motu with TOD timecode from the 744 and Boomrecorder successfully recognised and picked up the timecode.

Any reason why this setup might give problems, or any suggestions?

thanks

Mick

Yes--this has worked great for me just as you describe.  All the concert etc recording I've done in the last few years has been done to Metacorder, with a Traveler (and an 8Pre coming in on ADAT and 4 more outboard mic pre channels) as well as the SD recorder used via AES.  I also use the SD box as my clock and TC source as well.  The SD preamps + convertors are a notch better than MOTU's, and have limiters as well, so I often save them for my "money" channels in that setup. 

Philip Perkins

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Thanks Philip, very interesting I'm investigating the 8Pre.

So you do connect the BNC wordclock out of the SD to the BNC wordclock in of the Traveler and then select 'Word Clock In' as the clock source? Does the 8Pre also need to be wordclock synchronised? Can you split wordclock out sources to two inputs?

I see the clock source on the Traveler can be any of AES, S/PDIF, Wordclock in, ADAT 9 pin, ADAT optical, SMPTE etc.

I cannot see any confirmation that the wordclock is OK?

many thanks

Mick

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Thanks Philip, very interesting I'm investigating the 8Pre.

So you do connect the BNC wordclock out of the SD to the BNC wordclock in of the Traveler and then select 'Word Clock In' as the clock source? Does the 8Pre also need to be wordclock synchronised? Can you split wordclock out sources to two inputs?

I see the clock source on the Traveler can be any of AES, S/PDIF, Wordclock in, ADAT 9 pin, ADAT optical, SMPTE etc.

I cannot see any confirmation that the wordclock is OK?

many thanks

Mick

In the Motu audio setup for the Traveler you can select what the clock source will be.  When using the SD recorder as the clock master you can use either WC (and hook up w/ a BNC cable) or AES (in which case you just need the AES feed you already have). My 8Pre talks to the Traveler via ADAT lightpipe, and I hook up a full circuit w/ the Traveler, both in and out.  I set up the 8Pre to clock itself to the incoming ADAT stream at the correct SR on its front panel, and that's it.  (You can clock the Traveler to incoming SMPTE, but then you have to give up an audio input to do so.)  To the Mac, this whole arrangement appears as a single firewire device, since the Traveler announces itself as a 22 output channel box.  (20 inputs if you include SPDIF and AES, + a stereo mix from CueMix Bus 1).  This avoids hassling with device aggregation, and all these inputs appear in a single iteration of CueMix.  If you add a device via device aggregation, Metacorder and BR will see them but you'll need as many iterations of CueMix open as you have interfaces to control them. Monitoring more than one iteration of CueMix is a hassle, and making a live mix with audio from more than one CueMix requires wired connections between the two interfaces, to make the output of mixer A appear as a pair of inputs in mixer B.  I've asked and asked MOTU to allow the mixers to talk to each other by some internal method, but they haven't addressed this issue to my knowledge.  (Power users of DP etc can monitor many many interfaces and make submixes from within the app, so I guess MOTU doesn't care about this shortcoming of CueMix.)

Philip Perkins

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Thanks again - I've ordered an 8pre - managed to find one stocked at the old price before the UK pound starting sinking fast in value against the dollar - so had to get it :-) (new price up nearly 25%).

I've realised that BoomRecorder can still derive the timecode from an audio input even if the Traveler itself is not clocked to SMPTE but to another source  eg. wordclock , AES , or SPDIF.

I was looking at the Metacorder site and saw that it might be able to derive timecode by another route other than a main audio input is this right?

Is clocking from SMPTE (from the 744T) as good as far as you know as wordclock (with SMPTE I get a reassuring red LOCK light AND a nice pulsing orange TACH light on the Traveler :-)

I was interested to see that you send the ADAT both ways from 8pre to Traveler and from Traveler to 8Pre and have the 8pre clock to ADAT does that work regardless of what the Traveler itself is clocked to.

I'm not clear why you have used device aggregation what advantage does device aggregation have if as you say the Traveler can appear with 22 outs (20ins)?

thanks again for all the very helpful information

Mick

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Thanks again - I've ordered an 8pre - managed to find one stocked at the old price before the UK pound starting sinking fast in value against the dollar - so had to get it :-) (new price up nearly 25%).

I've realised that BoomRecorder can still derive the timecode from an audio input even if the Traveler itself is not clocked to SMPTE but to another source  eg. wordclock , AES , or SPDIF.

I was looking at the Metacorder site and saw that it might be able to derive timecode by another route other than a main audio input is this right?

Is clocking from SMPTE (from the 744T) as good as far as you know as wordclock (with SMPTE I get a reassuring red LOCK light AND a nice pulsing orange TACH light on the Traveler :-)

I was interested to see that you send the ADAT both ways from 8pre to Traveler and from Traveler to 8Pre and have the 8pre clock to ADAT does that work regardless of what the Traveler itself is clocked to.

I'm not clear why you have used device aggregation what advantage does device aggregation have if as you say the Traveler can appear with 22 outs (20ins)?

thanks again for all the very helpful information

Mick

I get TC into Metacorder via the Mac's analog audio input, so I can avoid hooking it up to the interfaces.  I figure BR could do the same thing.

Clocking from SMPTE should be fine--it worked for me, and SMPTE clock is how I clock my Tascam HDP2 and the 702T with video cameras all the time and that has worked very well.

You need device aggregation if you want to use more than one interface box.  We dodge the bullet bit with the 8Pre/ADAT connection to the Traveler, which makes everything simpler and easier, and also gets the 8Pre off the FW bus.  If you wanted to add another interface beyond those, or add one that could not speak ADAT to the Traveler, you would have to aggregate it.  This works fine, it just means that you have to get more creative about monitoring if you don't want to monitor thru the recording app (and deal with all that latency).  In the last few months I've really been short on inputs with just 20, so I'm looking an seeking for my next step.

Philip Perkins

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  • 2 weeks later...

I used my Traveler with the 8Pre for the first time last night for recording live music and setting up in half darkness with a sound check going on I went to push in the adat plug to the 8pre found it difficult and discovered two of the tiny/flimsy plastic flaps on the lightpipe/adat sockets broken on the 8Pre which means the plug is now even less secure in the socket than before in fact barely stays in. I think it might have been broken somehow in transit (in a pelican case?)

Just wondering if there's a strategy to deal with these lightpipe/adat connections which means they are more secure and less likely to get broken/fall out/fail? Although 8 channels of 24 bit optical is impressive they are surprisingly poorly mechanically designed in my opinion.

Any suggestions welcome.

Thank you

Mick

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