Mic stops working after Dolby Digital passthrough begins

[brandon13]

The first microphone I bought to test out vox commando is a cheap $8 microphone I bought at a big grocery store. It works surprisingly well. It plugs into the 3.5mm microphone port on my sound card.

I am using a pci soundcard with a c-media chip and the open source cmediadrivers to run it. These drivers allow for bit perfect passthrough of Dolby Digital, DTS and PCM signals.

In testing vox commando I setup a command to go to my movie collection in windows media center. It worked perfectly. I went to the dvd library and started playing a movie with Dolby Digital. Then, I noticed the microphone was no longer working and vox was not hearing anything I was saying.

In short, my microphone stops working when playing Dolby Digital or DTS and also after waking my computer from sleep, which may be another problem.

Right now I am not sure if this is a limitation of my sound card itself, the open source driver I am using or the simple fact that I am bypassing windows audio processing using Dolby Digital Passthrough.

The microphone does still work when using Wasapi in Foobar2000, which bypasses Windows audio processing and the microphone still works with Vox Commando running so I'm almost leaning towards the problem being my sound card and/or drivers.

A USB microphone might solve this problem if that is the case.

Has anyone else run into this problem?

EDIT: I just tested out this scenario with windows sound recorder running and it had no problems. I tried it with Vox and sound recorder running and vox continued to recognize what I was saying, though with some problems due to the sound of the movie. Hmmm...This is more of a bug report now.

[jitterjames]

I am unable to test any kind of similar scenario since I only have hardware for analog audio output at the moment.  I think yours must be an unusual situation though, because I assume that other users are at least using some kind of hdmi output for their audio.

So, are you saying that having sound recorder running (recording) allows Vox to stay connected (when you start playing a movie with digital output), but if sound recorder is not recording, then Vox loses its connection to the mic?

That's pretty odd, although stranger things have happened.  All I can tell you is that Vox uses the default sound input device set up in windows, and that is the only option.  To re-establish the connection to the default input device, it is usually sufficient to switch to off mode (red) and then back to on mode (green).  (i.e. you don't need to restart VoxCommando).  Some users have had trouble with Vox losing connection to the mic after waking from sleep, and in this case, switching to off and then on mode successfully reconnects to the mic.

This is all pretty much handled within the windows api so if there is a bug in there somewhere, it is nothing that I can fix myself.  It is ridiculous that I must use the default input device with the windows speech recognition engine, but I have researched it and well, there it is.  the work arounds that I have found are extremely convoluted and would probably cause more problems.  Knowing Microsoft, it is not likely to change no matter how many people complain.

A possible work-around for you might be to switch vox to off mode and then back to on mode when you start playing a movie... Not ideal of course.

I would be interested to see if a usb mic solved your problem or not.  Honestly, neither outcome would surprise me!

[brandon13]

"having sound recorder running (recording) allows Vox to stay connected (when you start playing a movie with digital output), but if sound recorder is not recording, then Vox loses its connection to the mic?"

This is true, when using the digital out of the sound card.

But, if I set my sound output to the ati hdmi I don't have this problem. That is with the mic still hooked up to the sound card.

Turning Vox off and back on and/or restarting Vox does not recover the microphone until after I stop the movie.

Also, I tested out a usb webcam that has a microphone and it does not have this problem, but it isn't a great microphone.

So, for the time being , I just have it set to open sound recorder minimized when I tell it to open media center and to close when I tell it to close. Not ideal, but I don't even notice it.

[jitterjames]

Could it be that the default recording device is being changed somehow?  If the input is still working and set to default, then VC should be able to reconnect when you switch to off mode and then back to on mode.  Note that Off means red, not yellow mode.  When you say "restarting" do you mean actually closing VC and running it again, or do you mean hitting the restart button?

[brandon13]

Interesting.

The default recording device wasn't being changed, or it didn't look like it. I could tell, though, that the usb cam with mic started picking up the sound instead of the one that should be.

Without the usb cam hooked up it was still cutting the sound from the microphone. Maybe it was switching to a device on the sound card or tv tuner with nothing connected to it.

I disabled all recording devices except the microphone I want to use but still no dice.

Weird enough, I tried it out today and for the first time it's not giving me any problems. Maybe it just needed a reboot since disabling all recording devices except that one as I didn't test it out too much after doing so.

Fingers crossed.