Post by Ian JacksonI think it was 'Stereo Mix' (which, I believe, is payware) that I once
tried on a W7 Dell D630 laptop because it had no native mixer stereo mix
function, and Audacity wouldn't record streamed audio. As it was
payware, I only tried it - and as I could use Audacity on another PC, I
didn't buy it.
https://en.wikipedia.org/wiki/Sound_card
"Crippling of features
Most new soundcards no longer have the audio
loopback device commonly called "Stereo Mix"/
"Wave out mix"/"Mono Mix"/"What U Hear" that was
once very prevalent..."
Well, that section is a bit hyperbolic. HDAudio devices
are highly likely to have the path in hardware. It's a
matter of unticking the "disabled devices" in the sound
control panels of Windows, to bring it back. Microsoft
says "it will confuse people", but of course that's
bullshit. It's disabled to make people think their
hardware company is heartless.
Some of the more expensive sound cards, use separate
I2C DACs and ADCs. And you might theorize that this
sort of design would prevent the feature from working.
But the main chip that hosts the I2C busses, has
mixers inside it, and the mixers will have the
same standard audio design as before. Complete
with the stereo mix path.
I've only seen one chip so far, where the
designers screwed up. One of the first HDAudio
chips (basically derived from older AC'97 designs),
they managed to forget to put the microphone
boost section into the chip design. Later
chip model numbers, had that put back in.
So that one chip ends up with microphone
input you cannot really hear.
Manufacturer audio drivers have rather large
INF files (15KB of text). And a lot of the
internal routing is done in there. It would
only take a "slip of the pen" to lose features
in that mess. But generally, the stuff is all
there, as long as the software is willing.
When HDAudio first came out, the datasheets for
the devices were written in "widget-ease", a kind
of useless text description of functionality. A
big missing item, was a diagram of the mixer paths.
(The hardware designers need this, to make sure
they don't forget something!)
Fortunately, some less kooky datasheet writers
have survived, to write more conventional datasheets
for modern devices. And the all-important mixer block
diagram is included, where you can see for yourself
that a stereo mix path is in the hardware. So
I can confirm there is no RIAA conspiracy at the lowest
levels of the hardware.
So the next time you don't have a stereo mix, at the
very least you can look up the datasheet for your
HDAudio chip, and see if there is a mixer block
diagram. Then find a Windows Recipe for putting the
item back where it belongs.
Paul