UB-MADI sample rate problem

[BC Keller]

Hi Folks,

Testing new gear here. And came across a rather strange thing. As I was typing the message, I actually came up with the solution, so editing the post to help other trouble shoot in the future.  Here is the process I encountered.

We purchased the UB-MADI to connect a Mac to a Digico SD9 from the computer USB port to the MADI ports on the SD9. And it works. Almost.

Installed the driver (v1.0.0 so you know it's fully tested) from DigiCo. That seems to be the latest (and only). It shows up in the pref's with no problem. Shows up in Qlab to patch. No problem. But when I play items through the digico, they are slightly "chipmunked". Hmmm. Sample rate problem?? I thought Qlab was awesome about being able to play (just about) anything, and it coming out just fine. Most interesting.  Poked around in the settings on the mixer, tried it with the console as clock source and the MADI as clock source, and same problem existed. I converted the audio file to be 24 bit 48kHz, and still had the same problem. I played the file from the internal computer speakers, and it sounds just fine. Checked the "Guarantee Synchronize" button. Still, same problem.  So then I played two files of same song, triggered together, one selected to built in inputs, one to the DigiCo. What was interesting, in the Qlab GUI, after one minute of play, the active cues pane say they are both in time. However, if you look in the "Action" column, showing the time played/remain, they are almost 5 seconds off from each other. Drift? Internal to the compute/Qlab? Most curious? 

That's when I started to write this post, and remembered the hardly used, but very important app, "Audio MIDI Setup".  Opened that up, and sure enough, in the "Audio Devices" you can select the UB MADI. And sure enough, you can change the sample rate format on both the input and output. The input was selected to 44.1kHz. Changed that to 48kHz, and all seems to be fine, for now.

Still testing, so I don't want to fully endorse this as a working model. But, it's now looking good.

The students are wanting to try to use the UB MADI to do Qlab playback AND multi track archive recording of the show. On the same computer. Should be interesting. We shall see if it's possible.  (different hard drives for playback and recording, just so nobody panic's). 

Anyhow, something to help the next group that tries the UB-MADI out. No clue why that was selected to 44.1, but, it's right now. Gotta love it when the solution is easy.

Cheers,

BC Keller

Production Sound Supervisor

Claire Trevor School of the Arts

University California, at Irvine

[Joey Buddenberg]

Thanks BC. I just ordered an UB Madi to be used with my SD11 and QLab.

Saves me a headache...

Joey

[Who are you]

Hey Guys, anything new on your UB-MADI interfacing a MAC with DiGiCo consoles yet ?  

I am on the verge of making the move to UB-MADI for our play mixed on a D5T.

thanks for your updates :)

JB

[BC Keller]

Hey JB,
We used it for our Radio Plays Festival. And it went well. There was one phone call where the students lost signal, and over the phone, figured out it was the same issue listed above, the Audio/MIDI set up switched it to 44.1. Once 48k was set again, it worked like a charm. Not sure what/who caused it to change to 44.1. But it only did it the once. After that, it was great. It's a great way to get Qlab into the SD9 with out eating up the few analog inputs at the console.

[raymond soly]

if you want to know if it works the answer is yes……I am using it on an A&H ILive console , no reason this shouldn't work on a digico, although I haven't done both play back and recording on the same computer (nor would I want to do that anyways) but it works very well with Qlab …..

Ray

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[BC Keller]

OH yes, forgot about the notion of record and playback from same computer. We did try it in the workshop, and it worked fine. We did *NOT* implement it in the show. Felt it was too much of a gamble.

Nice to see it works on other boards too!

Cheers,
BC Keller
Production Sound Supervisor
Claire Trevor School of the Arts

UC Irvine