Mike Easter  wrote:
> Computer Nerd Kev wrote:
>
>> https://en.wikipedia.org/wiki/HDMI
>>
> When I started to employ my 3B RPi using some leftover parts, I had a
> VGA monitor and USB kb & mouse, so I needed an HDMI to VGA adapter.
> There were places that had adapters w/ a 3.5mm for audio, but I opted
> for an adapter w/o audio plug outlet in favor of just using the RPi's
> audio outs for some little 'computer speakers'.

Bluetooth speakers may be another option for Pis with wireless. These
again receive digital audio and have built-in DACs.

> But, I'm puzzled about the analog vs digital.  I would assume that the
> HDMI audio is digital,

It is.

> but the 3.5mm plug sounds/looks like an analog audio outlet.

It is.

> But, I'm sure those HDMI to VGA adapters w/ audio plug aren't converting
> digital to analog audio.

They are actually, and VGA video is analogue as well, which is
actually a much bigger ask. All the devices probably use a similar
chip which has been developed to integrate the whole functionality
into one $0.40 lump which just needs to be soldered onto a circuit
board with a few other parts like the plugs and sockets. Quite
possibly the cheap devices (maybe the expensive ones too) use chips
from some unheard-of Chinese company that doesn't care about quality
but sells them cheap enough to put in a $10 adapter. The few
additional components like filter capacitors could also have been
stuffed up, causing noise to be introduced to the analogue audio
output. All the same, the chip itself most likely uses a real DAC
which is better quality than that used for the onboard analogue
audio from the Pi, and so in theory the result should be better
quality.

>  What is the answer to my confusion?

For better audio you want a well designed DAC. It can connect to GPIO,
HDMI, or bluetooth, all equally effective at conveying the same
digital audio signal from the Pi.

What you get with the onboard analogue audio output on the Pi is a
cheaply designed (for probably justified reasons) DAC which also uses
the same digital audio data, but produces analogue audio using a
function of the SoC hardware that was not designed to be used as an
audio DAC. As such the results are not optimal.

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