Base Volume Level

[bricabrac]

Hello,

Hope someone would be able to shed some light on the following matter. I am wondering what volume level on core and/or menu settings is the "base" level, i.e. where no "amplification" nor "attenuation" of digital signal is performed? I know that digital volume control degrades digital sound signal and as I am thinking of connectin MiSTer to power DAC via toslink cable and control the volume there, I would like to have as clean (unmodified) digital output from each core as possible. Any info on this will be much appreciated.

kind regards,
Kamil

[Malor]

For digital signals, AFAIK base level is max volume, and that's where everything defaults. The signal sent through both HDMI and Toslink is at max volume/full resolution by default. (it's the same signal down both cables.) You can turn it down, but not turn it any higher.

You may want to also set this:

hdmi_audio_96k=1

which changes to a 96KHz sampling rate. If your DAC will support that, apparently you will get higher quality sound from cores that use weird sampling rates; there's one core that uses 33KHz. I gather these will mix more cleanly into a higher rate signal.

I drive a receiver this way, and it sounds excellent.

Note that even the analog board has a mini-Toslink out. The digital board gives you both mini- and full-size Toslink ports.

[FPGA64]

Dont use the 96k option. It may give issues with certain capture equipment.

[bricabrac]

For digital signals, AFAIK base level is max volume, and that's where everything defaults. The signal sent through both HDMI and Toslink is at max volume/full resolution by default. (it's the same signal down both cables.) You can turn it down, but not turn it any higher.

You may want to also set this:

hdmi_audio_96k=1

which changes to a 96KHz sampling rate. If your DAC will support that, apparently you will get higher quality sound from cores that use weird sampling rates; there's one core that uses 33KHz. I gather these will mix more cleanly into a higher rate signal.

I drive a receiver this way, and it sounds excellent.

Note that even the analog board has a mini-Toslink out. The digital board gives you both mini- and full-size Toslink ports.

Thank you very much for the detailed answer. I will stick to the max volume then. And I am gratefull for letting me know about the hdmi_audio_96k setting. Just based on the name I was positive it only applies to HDMI. This knowledge might definitely come in handy.

[Malor]

Dont use the 96k option. It may give issues with certain capture equipment.

If you're not capturing anything, would it matter? I'm driving a receiver with a Toslink cable, and it works very nicely in 96K.

I would anticipate that, in 2022, almost any quality gear that takes Toslink inputs should handle 96K. My receiver is from 2009, and I'm pretty sure 96K was old even then.