Sync issue between M-audio speakers and Decklink at DVinfo.net

Bogdan Apetri · September 11th, 2005, 08:17 PM

Hi!

I've set up a FCP HD system as follows:

- the video goes through a Blackmagic Deckling Pro card to a JVC professional monitor

- the audio goes through an M-Box connected through USB to my G5 to 2 m-audio bx8 speakers

I am noticing a very apparent sync issue between my video and audio. I think it's the video that takes just a tiny bit longer to go through to my monitor.

Any ideas? I could connect my speakers directly to my Decklink Pro card (it has audio outputs). Would that eliminate the sync issue?

Thanks for any ideas.

Zach Mull · September 11th, 2005, 09:45 PM

I bet running sound from the Decklink would fix it. This same things happens in FCP if you try to watch external video over firewire and monitor audio through the built-in sound card on the Mac. Running the audio from the same source as the video has always eliminated the sync issue for me.

Bogdan Apetri · September 11th, 2005, 10:14 PM

Thanks Zach.

I was just wondering about the quality of the Decklink card (primarily built for video) as compared to the M-Box (built for audio). Soundwise, of course.

Also, if I go through Decklink, I would lose sync between audio and the main computer screen, on the other hand - as opposed to the JVC monitor.

I guess you always win something, lose something.

Zach Mull · September 12th, 2005, 01:04 AM

Hmm, that is a valid concern. What type of audio outputs does the Decklink card have? What do you use when you print to tape through the Decklink? I just looked at the Blackmagic website and saw that at least some of the cards have AES outputs. Is it possible to route that to the S/PDIF in on the Mbox and monitor that way? I wish I knew this already - my Mbox is coming by UPS tomorrow afternoon. It seems a little odd to go out of a card and into the USB device to go out again to the monitors, but I have to assume that using AES and S/PDIF is lossless since they're digital. But I bet if there's an output that you could route directly to your monitors, that would be best. Of course, I am about one step above clueless when it comes to audio. Maybe you should post in Now Hear This and see what the pros say.

September 11th, 2005, 08:17 PM	#1
Bogdan Apetri Regular Crew Join Date: Oct 2003 Location: New York, USA Posts: 117	Sync issue between M-audio speakers and Decklink Hi! I've set up a FCP HD system as follows: - the video goes through a Blackmagic Deckling Pro card to a JVC professional monitor - the audio goes through an M-Box connected through USB to my G5 to 2 m-audio bx8 speakers I am noticing a very apparent sync issue between my video and audio. I think it's the video that takes just a tiny bit longer to go through to my monitor. Any ideas? I could connect my speakers directly to my Decklink Pro card (it has audio outputs). Would that eliminate the sync issue? Thanks for any ideas.

September 11th, 2005, 09:45 PM	#2
Zach Mull Major Player Join Date: Feb 2005 Location: Portland, OR Posts: 273	I bet running sound from the Decklink would fix it. This same things happens in FCP if you try to watch external video over firewire and monitor audio through the built-in sound card on the Mac. Running the audio from the same source as the video has always eliminated the sync issue for me.

September 11th, 2005, 10:14 PM	#3
Bogdan Apetri Regular Crew Join Date: Oct 2003 Location: New York, USA Posts: 117	Thanks Zach. I was just wondering about the quality of the Decklink card (primarily built for video) as compared to the M-Box (built for audio). Soundwise, of course. Also, if I go through Decklink, I would lose sync between audio and the main computer screen, on the other hand - as opposed to the JVC monitor. I guess you always win something, lose something.

September 12th, 2005, 01:04 AM	#4
Zach Mull Major Player Join Date: Feb 2005 Location: Portland, OR Posts: 273	Hmm, that is a valid concern. What type of audio outputs does the Decklink card have? What do you use when you print to tape through the Decklink? I just looked at the Blackmagic website and saw that at least some of the cards have AES outputs. Is it possible to route that to the S/PDIF in on the Mbox and monitor that way? I wish I knew this already - my Mbox is coming by UPS tomorrow afternoon. It seems a little odd to go out of a card and into the USB device to go out again to the monitors, but I have to assume that using AES and S/PDIF is lossless since they're digital. But I bet if there's an output that you could route directly to your monitors, that would be best. Of course, I am about one step above clueless when it comes to audio. Maybe you should post in Now Hear This and see what the pros say.