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Old October 20th, 2009, 10:55 AM   #1
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5.1 Surround Monitoring and HDMI

As I contemplate some improvements to my video editing station, I think I'd like to set up 5.1 surround sound monitoring. Insofar as I was also thinking of getting a Matrox MXO2 Mini to monitor my video via an HDMI-equipped HD video monitor, it occurred to me that the HDMI out of the Matrox carried 8 channels of audio as well.

I thought it made sense to route that HDMI audio to an audio amplifier to drive my 5.1 speakers but I haven't been able to find an amplifier with an HDMI jack. Does such a beast exist? Is there a flaw in my (theoretical) approach? Any guidance would be greatly appreciated!

Thanks
TVH
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Old October 20th, 2009, 09:36 PM   #2
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the MXO2 has 6 discreet analog channels out. just plug your matched self powered speakers in and go... they approach you are looking to do won't yield what you want, at least not without spending more then you want. I'd expect that the display might decode back out to 6 analog outs... and you are right back to where you started with, and bought would I would assume to be a very expensive monitor. there might be some amp out there that can extract from the HDMI signal, but again you are back out to analog... or you could just use the 5.1 outs on the MXO2 in the first place and save a lot of time.
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Old October 21st, 2009, 12:10 PM   #3
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If only...

Steve,

Thanks for taking the time to reply. It is true that I have to get back to analog at some point but I was hoping just to use the available information streams as efficiently as possible. Unfortunately, while the much more expensive MXO2 does have 6 outputs, the MXO2 Mini only has two. In the end, that may be an argument for buying the more robust unit but is not an approach that would work with this version.

As to the video monitor issue, one of the claims Matrox makes for both units is that you can get credible video monitoring out of a "normal quality" HD HDMI-equipped monitor because of their included calibration software. So, no, the video monitor itself would not be expensive.

I am thinking there must be HDMI-equipped surround sound amps out there but they are probably consumer oriented grade and not necessarily suited fro driving reference monitors?
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Old October 21st, 2009, 12:38 PM   #4
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I've never had a need to look at a consumer level HDMI amp that could extract the 5.1 and send it out to the speakers. probably out there... but not what I would want to mix on. maybe for some quick tests, sure, but the problem is these consumer setups have pretty peaky sounding setups.. and they are all a little bit or more different. in the end I have found that to get to a certain level of quality, you have to spend X amount no matter which approach you take. it then becomes a question of which way gets you the best results for the least amount of hassle. in this case, you may well be better off stepping up to a MXO2 and some decent self powered speakers. for the price the M audio BX5a's are clean monitors that are ok for dialog editing, and have some bottom end. only minor problem is you can only by them in pairs... so you have a spare speaker sitting around ( ebay ! )
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Old November 10th, 2009, 03:21 PM   #5
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I constructed my studio in my basement. I figured while I was at it, I'd wire it for surround sound. Quite frankly, I overestimated the demand for surround work. I'm not sure anybody other than Hollywood movies use it. I haven't even bothered to set it up - well it's wired if I need it.

But let's say you have a use for it. This is the issue you're going to run into. Bass Management. Now a consumer receiver with HDMI (there are plenty of these) expect an AC3 encoded surround sound signal. What you are trying to send it is 6 discreet channels. Even if you could route it somehow you'll run into issues with Bass Management. The way surround sound systems typically work is they take the bass frequencies below 80hz from all the channels and send it to the subwoofer with the low-frequency channel. Theoretically you could monitor with 5 discreet speakers with decent bass response. But you really should monitor with Bass Management otherwise you may create some phase issues that cancel out bass frequencies when someone plays it back on a consumer surround sound system.

If you're on the PC using Vegas, Voxengo makes a plug-in that will do Bass Management. It takes some tricky routing, but it's possible. Bass management system plugin - BMS - Voxengo I haven't used it, since I'm on the Mac.
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