Kanex HDMI adapter audio adjustment

Question

I set up a Mini connected to a 26" Sony LCD in my kitchen. The computer and cable box live in the cabinet below the TV and the wires pass through a conduit in the wall to keep it neat. To minimize the amount of wire that I had to fish through the conduit I got the Kanex Mini Display Port to HDMI with USB Audio adapter. Two HDMI cables and a small wire for the IR repeater are all that I have in the conduit.
Everything works very well so far with one exception. Changing the audio on the Mini does not affect the audio going to the TV. I was not expecting this but found a review online that referred to this issue so I thought it was normal. I wrote to Kanex and the response from their support said that the audio should be adjustable on both the USB and Digital audio models and they issued me an RMA.
Does anyone have any experience with this adapter? Their support could be wrong (it wouldn't be the first time tech support gave me some bs) or perhaps I should just get a replacement. I also have the option of getting the Digital Audio version of the adapter ($10 more). Last option would be to get a cheaper display port to HDMI adapter and fish two RCA cables through the conduit for audio. That would be cheaper but more of a hassle since the HDMI cables are pretty thick and the conduit is cramped already.
Thoughts?
Thanks.

Answer 1

If you are referring to changing the volume on the Mac mini and this not resulting in a volume change on the TV (via the Kanex Digital HDMI adapter) then this is normal and correct behaviour.
With the Kanex Digital HDMI adapter, the Mac is outputting audio via the digital TOS-Link connection, and should in most cases be merely passing through unaltered the digital audio from your video file or DVD. With digital signals, the volume is actually part of the analogue waveform that has been encoded as digital data, volume changes actually involve changing the analogue waveform of the sound, and as you as in this scenario are passing a digital signal there is no access to the analogue waveform to allow modifying it to change the volume.
So how do TVs receiving audio via (digital) HDMI change the volume you might ask. Well I am glad you asked they are able to do this because like all devices actually playing sound they need to and do convert the digital signal to analogue before playing it. This is done by a device generally referred to as a DAC - Digital Analogue Converter see http://en.wikipedia.org/wiki/Digital-to-analog_converter once the TV has converted the signal to analogue it can then modify the waveform to alter the volume.
What might be worth considering, is that if you are currently using the Apple Remote to control the volume on the Mac mini, you could instead get a Logitech Harmony Remote and program it so that navigation/playback commands are the same as the Apple Remote, but the volume commands are not and are instead the same as your TV remote. Therefore you can press play/pause etc. and this will control your Mac but when you use volume up/down/mute this controls the TV (or AV receiver).