The (black) magic of HDMI

Weird evening. I want to measure the frequency responses of some sound bars with a focus on the bass end. First problem, my M-Audio Fast Track Pro microphone pre-amp/DAC won’t work. My recording software tells me that there’s an incompatible format. Or something. This is the first time I’ve tried to use it since upgrading the computer to Windows 8.1 from Windows 7. I do the usual rebooting and such all to no avail. I had previously installed the Win 8 drivers (dated middle of this year). I install the drivers on the Win 8.1 notebook and plug in the M-Audio. It works fine. I change the sampling frequency from the default 44.1kHz to 48kHz. Now it won’t work.

I switch the M-Audio back to the main computer, select 44.1 kHz and it works on that. Good enough for bass work.

I put my pink noise test CD into the Oppo BDP-103AU player and start it up. No sound. Picture through the Pioneer receiver, but no sound. The sig info indicates no signal being received. Weird. I switch everything off and on again. Same state of affairs. I switch to a commercial CD. No sound. I fiddle with the Oppo settings. Nothing. I try the CD in another player. It works. I switch on a PVR and switch the Pioneer to it. It works. I switch back to the Oppo and pop in a Dolby Digital DVD. It works with nice 5.1 sound. I switch the Oppo over to network mode and have it play back a 44.1kHz FLAC. It works!

I pop the commercial CD back in. Nothing.

I do a factory reset on the Oppo. No sound.

I google for possible answers. Nothing obvious.

I hot swap* the HDMI cable from the PVR to the Oppo and switch the Pioneer over to it. CD sound! Amazing CD sound!

I hot swap the HDMI cables back to where they belong. Switch the Pioneer back to the Oppo’s input. No sound.

I pull the HDMI cable at the Pioneer end. Wait a few seconds. Plug it back in. Wait. A couple of seconds and finally, at last, sweet, sweet music.

So apparently some fault in the connection allowed PCM audio to flow when it originated from a FLAC file on a networks server. But not when it — the exact same stuff — originated on a shiny optical disc.

Go figure.

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* Hot swapping definitely not recommended. But I was getting desperate.

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