Computer Nerd Kev  wrote:
> Mike Easter  wrote:
>> bob prohaska wrote:
>>> Has anybody noticed a material difference in audio quality between
>>> the headphone jack and what comes out of the HDMI port?
>>
>>
https://raspberrypi.stackexchange.com/questions/47699/sound-output-of-the-raspb
erry-pi
>>
>> Someone suggested that if you want really good audio, to use a card for
>> the GPIO header:
>> https://elinux.org/index.php?title=RPi_Expansion_Boards#Sound
>
> The GPIO header allows connection to the PCM audio output signals.
> These are the digital signals used to generate the analogue audio at
> the headphone jack using a DAC (apparantly a very cheap
> implementation using PWM according to the Stack Exchange link).
>
> A quick look on Wikipedia indicates that HDMI also carries PCM audio,
> so in theory HDMI audio should be equally good as the audio from the
> GPIO because they're actually the same data (ignoring optional
> formats over HDMI which might be slightly better in some specific
> respects than the PCM - no idea if the Pi supports any of those, or
> how they're any better for that matter).
>
> https://en.wikipedia.org/wiki/HDMI
>
> USB sound cards probably use PCM as well, though I don't know if the
> bitrate limits might be lower, and some apparantly introduce a
> delay. As far as quality goes it's most likely to be the DAC that
> really counts, and anything sold as an audio adapter should be better
> than PWM unless it's a complete rip-off.
>

IIUC, the transition from digital to analog audio then occurs in the
monitor, if using the HDMI connection, or the Pi itself, if using the
headphone jack. Have I got this much right?

I've tried using the audio output on a Dell ST2200L HDMI monitor and the
headphone jack, neither showed any obvious defects.

Thanks to all for reading and posting informative links.....

bob prohaska

test

--- SoupGate-Win32 v1.05