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Arlen Holder Arlen   Holder is offline
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Default Typical first pass tutorial process on Windows 10 where NONE of the extent how to articles actually tell you what you really need to do!

On Fri, 06 Nov 2020 05:55:52 -0500, Paul wrote:

What's interesting (to me), is the Stereo Mix is really a mixer,
but the software doesn't allow it to be controlled that way.
Stereo Mix is much more than just LineOut.
https://i.postimg.cc/dVDTpv8G/AD1988B.gif
Use "Download original image" to see the full scale version.


Hi Paul,

Thanks for helping out so all can benefit from what you've learned, where I
just downloaded that ADI "AD1988A/AD1988B Functional Block Diagram":
o https://i.postimg.cc/dVDTpv8G/AD1988B.gif
Name: AD1988B.gif
Size: 79285 bytes (77 KiB)
SHA256: A0EA9DE570BBF49A89882E3B79963C39BC396D68D9F8B73CF9 E00DF2E7EE49C2

The picture was twice that scale, but the site wouldn't
accept it, so I had to scale it down a bit.


These are full-sized 20-page PDFs which are easier to search for keywords:
o https://www.hardwaresecrets.com/datasheets/AD1988A_1988B.pdf
Name: AD1988A_1988B.pdf
Size: 1434129 bytes (1400 KiB)
SHA256: 899F6E7A84FF62BC6A39A501FA20446C3D4F2B4FFDF9E87741 E21019B9ABC53A

o https://www.analog.com/media/en/technical-documentation/obsolete-data-sheets/AD1988A_1988B.pdf
Name: AD1988A_1988Ba.pdf
Size: 2092821 bytes (2043 KiB)
SHA256: 4010B5C24B910D75CC5835AC3C11D45EB5A3A55357F1FE10EB 3C82911B0191DA

The AD1988B claims to use 32-bit math (to avoid overflow),
which tells me that parts of that diagram are digital and
not analog as the "functional" diagram might claim. The
mixer is doing the summation of 8 channels of 24-bit each,
so this would be 27-bits to avoid overflow. They don't say
whether it's fixed point or float, but fixed point
would be easier for them.

The diagram is kooky, compared to how the GUI on the
computer appears and works. It could for example,
be mixing 7.1 down to stereo, but with a transformation
or what ? Perhaps the driver just says "screw it" and
passes only LineOut through.


I will take a look at the diagrams, but wanted you to have them also.

Notice the "Node ID 2D"
o 2D, Stereo Mix-Down, Audio mixer, Mixes the stereo L/R channels to drive MONO_OUT

But before I look, can you explain _why_ you picked _this_ particular chip?
--
FEATURES
o Ten 192 kHz DACs
o Five independent stereo DAC pairs
o 7.1 surround sound plus independent headphone
o Independent 8 kHz, 11.025 kHz, 16 kHz, 22.05 kHz, 32 kHz,
o 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz
o sample rates
o Selectable stereo mixer on outputs
o 16-, 20-, and 24-bit PCM resolution
o Six 192 kHz ADCs
o Three independent stereo ADC pairs
o Simultaneous record of up to three stereo channels
o Support for quad microphone arrays plus independent
o capture channel
o Independent 8 kHz, 11.025 kHz, 16 kHz, 22.05 kHz, 32 kHz,
o 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz
o sample rates
o 16-, 20-, and 24-bit resolution
o S/PDIF output
o 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz
o sample rates
o 16-, 20-, and 24-bit data widths
o PCM, WMA/PRO, Dolby®, AC3, and DTS® formats
o Digital PCM gain control
o Digital PCM ADC/stream mixer
o S/PDIF input
o 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, and 192 kHz
o sample rates
o 16-, 20-, and 24-bit data widths
o PCM, WMA/PRO, Dolby, AC3, and DTS formats
o Digital PCM gain control
o Auto synchronizes to source High quality stereo CD input with GND sense
o MONO_OUT pin for internal speakers or telephony
o Retasking jack support

ENHANCED FEATURES
o Three stereo headphone amps
o AD1988A: Windows Vista Operating System Premium Logo
o compliant
o 95 dB outputs
o 90 dB audio inputs
o AD1988B: Windows Vista Premium Logo compliant and
o Dolby Master Studio compliant
o 101 dB outputs 92 dB audio inputs
o Internal 32-bit arithmetic for greater accuracy Impedance and presence detection on all jacks
o Analog PCBEEP and digital synthesis BEEP
o C/LFE channel swap
o Two general-purpose digital I/O (GPIO) pins
o 3.3 V analog and digital supplies
o Reduced support components
o Advanced power management modes
o 48-pin LQFP and LFCSP_VQ package options, Pb-free
o Supports Andrea Active Noise Reduction headphones
o Hardware volume control
o Built-in microphone gain amps
o Adjustable microphone bias pins