MiSTer FPGA Forum

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

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.

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

Malor wrote: ↑Tue Jan 10, 2023 10:13 am

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.

FPGA64 wrote: ↑Tue Jan 10, 2023 10:48 am

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.