hardware gain option

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schsst
Posts: 25
Joined: Tue May 21, 2019 10:13 pm

hardware gain option

Post by schsst » Thu May 30, 2019 3:21 pm

Hi does the "hardware gain" option in "audio hardware" menu affects the quality of sound? I hear some differences whit this option set to on or off: is it a placebo effect...?

blaubär
Posts: 1359
Joined: Tue Apr 02, 2019 6:48 am

Re: hardware gain option

Post by blaubär » Thu May 30, 2019 4:33 pm

schsst wrote:
Thu May 30, 2019 3:21 pm
Hi does the "hardware gain" option in "audio hardware" menu affects the quality of sound? I hear some differences whit this option set to on or off: is it a placebo effect...?
I'll try to describe it as far as I understand :

If you have activated this option ( which is the default ), then the right slider shows the smartphone's ( also called DAC = Digital Analog Converter ) main volume settings on a scale from 0 to 100 %, which you then can set here ( and with the smartphone's usual volume control buttons of course ).

If you deactivate it, the contents of the slider changes, it takes top position, and the scale goes from 0 to -60 db. You can then lower the volume by lowering the slider. This then works as a further lowering of the preamp, and doesn't affect the smartphone's main volume. If you change the main volume by pressing the smartphone's volume buttons, then for about half a minute the hardware gain slider ist shown, and during this time you change the main volme there, too.

As to the sound quality : this is only a question of where to control the volume, in the preamp stage ( part of neutron's digital signal processing ) or in the smartphone's digital analog converter. If you do produce distortions e.g. by excessive equalizer and preamp increases then these will be mitigated by reducing the preamp volume, not by reducing the main volume, so in this very special case there would be a difference in sound quality.

by the way : if you have activated the Preamp-Switch in the lower panel, then the preamp will be shown, and neither the hardware gain nor the special preamp reducment described above

So, did I get this right ? I'd appreciate feedback.

blaubär
Posts: 1359
Joined: Tue Apr 02, 2019 6:48 am

Re: hardware gain option

Post by blaubär » Thu May 30, 2019 5:32 pm

As to the volume controls, I think we can best describe the situation as having three of them :

- the "preamp", directly after the signal has been decoded, before DSP ( digital signal processing = equalizer, crossfeed, ... )
- the "gain" ( the right slider if we disable the "hardware gain" option ), between DSP and DAC
- the "hardware gain" aka smartphone volume, which is part of the DAC ( digital analog converter ) or the amplifier, both being parts of the smartphone hardware

In the following screenshot the preamp would be situated at the beginning of the player, the gain at its end, the hardware gain somewhere in or between the dac and amp.

Z3iBYR6.jpg
Z3iBYR6.jpg (19.34 KiB) Viewed 1061 times

schsst
Posts: 25
Joined: Tue May 21, 2019 10:13 pm

Re: hardware gain option

Post by schsst » Thu May 30, 2019 8:34 pm

@blaubär yes you got it right; so if I set the "hardware gain" option off, I can always recall the hardware gain slider by the smartphone's volume buttons or by the button on the cover art on the "now playing" screen, right? so that option is only a different way to recall that slider, it does not affects sound quality.

schsst
Posts: 25
Joined: Tue May 21, 2019 10:13 pm

Re: hardware gain option

Post by schsst » Thu May 30, 2019 8:36 pm

(I always set preamp = 0 and gain = 0)

blaubär
Posts: 1359
Joined: Tue Apr 02, 2019 6:48 am

Re: hardware gain option

Post by blaubär » Fri May 31, 2019 6:16 am

schsst wrote:
Thu May 30, 2019 8:34 pm
so if I set the "hardware gain" option off, I can always recall the hardware gain slider by the smartphone's volume buttons or by the button on the cover art on the "now playing" screen, right?
As to the buttons in the top and lower right corners of the album art : they don't control the volume, at least not for me, but switch between different album arts in case you have more than one

schsst
Posts: 25
Joined: Tue May 21, 2019 10:13 pm

Re: hardware gain option

Post by schsst » Fri May 31, 2019 2:34 pm

I have four buttons on the cover art: gain (top left), show/hide album art (bottom left), img up (top right) and img down (bottom right).

blaubär
Posts: 1359
Joined: Tue Apr 02, 2019 6:48 am

Re: hardware gain option

Post by blaubär » Fri May 31, 2019 4:01 pm

Yes, you're right ! I forgot the gain button on the cover art !

schsst
Posts: 25
Joined: Tue May 21, 2019 10:13 pm

Re: hardware gain option

Post by schsst » Fri Aug 16, 2019 8:38 pm

when using a powerful dac/amp (dragonfly red) with low impedance headphones, the volume is too high.
For the best audio quality is better to lower the preamp or the gain? (i will use hardware gain to control the volume while listening)

blaubär
Posts: 1359
Joined: Tue Apr 02, 2019 6:48 am

Re: hardware gain option

Post by blaubär » Sat Aug 17, 2019 5:16 am

schsst wrote:
Fri Aug 16, 2019 8:38 pm
when using a powerful dac/amp (dragonfly red) with low impedance headphones, the volume is too high.
For the best audio quality is better to lower the preamp or the gain? (i will use hardware gain to control the volume while listening)
practical answer : doesn't matter at all, increasing preamp and/or equalizer can be a problem, but nothing else

theoretical answer : when you take a digital number with a certain number of non-zero-bits, and multiply it with a very low number, then the resulting number will have less non-zero-bits, so you'll decrease the bit-depth of your music by lowering the volume. if you reduce the volume in some intermediate step of processing and re-amplify it in a later step you won't re-create the lost bits. but you'd have to reduce either preamp or gain practically to zero (less then -60 db or so) to make this effect relevant, as internal processing has more bits then enough. when in doubt use 64 bit processing.

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