MXO Audio background noise

[visualvideoes]

Hi,

I have a MacPro with ATI 5870HD card. There is a background noise with Lion drivers 2.2. Solution??

Thanks

[Matrox_Support_Joe]

Sorry for missing your post. How would you describe the background noise? Does it sound like a ripple in the audio?
_________________
Regards,
Joe
Matrox Video Technical Support

[matroxtest]

I seem to have the same but with Snow Leopard.

FCP 7.0.3
Snow Leopard with all current updates
2007 8 Core Mac Pro 3.0ghz upgraded with an ATI HD 5870
Matrox MXO software v 2.1.18
Audio monitored on SDI 1&2

I have all my studio audio sources running through a Sony 5.1 receiver, nothing special, just being used as a stereo amp.

I'm getting this irritating line noise from the MXO stereo outputs. It's a pronounced hum and kicks in during playback and scrubbing but at no other time. Kinda sounds like the gain is set too high (probably using the term 'gain' incorrectly there, forgive me). It isn't present when I use an alternative audio output like my old USB sound sticks, only the MXO.

Definitely feels like the levels have somehow gotten out of whack. This receiver is new, seems to be fine for all other sources, it just the MXO FCP audio where I get the problem. My old one was fine. There are a couple of pieces of music in the project I am testing the system with, where I have edited (raised) the levels. They sounded fine with the other receiver and audio output devices but now get noticeably 'clipped' though the MXO.

I checked all connections, uninstalled and reinstalled the software, upgraded the cables, tried different inputs on the receiver, bypassed the receiver and fed it right to the TV that I use as a client monitor (same issue) looked for anything that might be shorting or touching the audio connectors, switched off my AC and the little unshielded fans that keep my RAID enclosure cool, all to no avail.

Still the hum It's def' coming from the MXO

Any ideas?

[matroxtest]

A quick correction in case anyone else reads this or might benefit from it.

My MacPro is actually a 3,1 from 2008 not a 2,1 from 2007.

The HD 5870 is a qualified MXO card and, and whilst it is tested by Matrox, it is not an approved by Apple for the MacPro3,1, and I have a sneaking suspicion this isn't a grounding issue but rather a symptom of some edge case.

In the MXO, the audio is **** through the DVI to retain sync. If it was a grounding issue, I tend to think that the hum would occur persistently. The fact that it only occurs on playback or scrub might indicate a system based incompatibility.

Plenty of reports about it working fine and it has served me well in all other use cases (although I have noticed a couple of glitches).

I might try a 5770 or a nVidia FX 4800 if I can pick one up cheaply.

[Matrox_Support_Joe]

Is the noise happening when playing back sequences in FCP? If so, what is your version of FCP?

As a workaround, can you try routing the audio in FCP to the sound card output?
_________________
Regards,
Joe
Matrox Video Technical Support

[Matrox_Support_Joe]

A good idea would be to try the Nvidia FX 4800 card and not the 5770 (since this might be too similar to the 5870).
_________________
Regards,
Joe
Matrox Video Technical Support