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Devices => PC's and Other Hardware => Topic started by: JimH on July 08, 2011, 01:59:15 pm

Title: Getting an AMD 6870 to support 5.1 output via HDMI
Post by: JimH on July 08, 2011, 01:59:15 pm

I bought an HIS AMD 6870 video card a few weeks ago, and connected it to a SONY STR-DH510 receiver, which is, in turn connected with HDMI to an LG TV 47LE8500.

No matter what I did, I couldn't get it to find more than two speakers.  In Windows Sounds, it saw the HDMI connection as HDMI Output, but when I double clicked on it to get to properties, it said under Supported Formats that it had a maximum of 2 channels (speakers) and it supported only 16 bit, 32 and 48Khz output.  It also said that HDCP was "no".

I tried a lot of things, most of which had no effect.  I updated ATI's Catalyst and the drivers that come with it.  Didn't work.  Still only 2 channels.

There were two other places where I updated drivers.  The one that worked was called "Controller Information ... HD Audio".  After a reboot, the properties page said I had 6 channels and HDCP was "Supported".  Encode formats added DTS Audio and Dolby Digital.

Seems like a long way around to solve a common problem.

Title: Re: Getting an AMD 6870 to support 5.1 output via HDMI
Post by: glynor on July 11, 2011, 04:31:04 pm

This is not typical.

When you said you were updating the drivers, were you using the Windows Update drivers or the latest Catalyst from AMD?  The Windows Update drivers for Graphics Cards are crap, and can never be counted upon to do anything but get bare-minimum functionality running.

For my 6870, all I had to do was install the latest Catalyst drivers from here: http://support.amd.com/us/gpudownload/Pages/index.aspx

Then, set the AMD HDMI device as my default audio output (I think this actually happens automatically, but it is worth checking).

Lastly, you will likely find that it works best to set Windows to "think" you only have two speakers connected in the Control Panel -> Sound -> Speaker Config dialog.  If you set Windows to 5.1, then for all stereo-only Windows Sounds (including audio from Flash on the web and whatnot) it will send the Front Left and Front Right channels correctly, but send the rest of the channels "blank", so your receiver will not use the surround-sound expansion on them to fill the other channels (it'll "think" there are 5.1 discreet channels there, and there are, just most of them are sending nothing).

This is annoying if you game because for games (that actually HAVE positional multichannel audio) you need to go back in and switch it back to 5.1 or you won't get the nice audio.  If you don't use games, it won't ever matter to you.

For MC, you should know how to set it.