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Raspberry Pi USB - some theory?

Bernd

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Oh, ok tnx a lot. Basic linux stuff - command line. Probably I need SU credentials (which I do not know/have). But fine, I'll check that out.
 

ZolaIII

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Simply as I could. The referred noise is from the power supply, usually not so good switching ones are used in Pi/PC. It can be pretty demonising regarding SINAD but that's about it. It's not what cause clicks and pops other sources of inter modular distortion in severe form can like for instance high straight radio waves. Each chip (DAC, AMP) has declared rejection rate of inter modular noise (but not up to the bottom of the spectrum at the advertised level), some are more prone in picking it up than others. This is more present in portable designs on properly designed desktop gear it's attended in many ways (larger capacitors, separate and better power lines, better separation between components and isolation...). The fix; better cleaner source of power either that you use good old deacent mobile phone charger or insert some power bank that you have lying around in between. Again this won't be hear able as some obvious deviation but it will be measurable regarding SINAD.
 

Bernd

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I'd expect it to expose the necessary bits already, but I suppose if you're using one of the hats with some controls for low level DAC chip options it might not have them. In that case you'd probably have to ssh in, or somehow install something like amixer-webui. I'm guessing though - it's not a distro I've tried as it used to be Roon-only, but XL might be worth a closer look.

Oh, cool. I did not know that existed. Thanks a lot - I will try to get that working.
 

Bernd

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Well, basically to normalize the output db level (I find the output level variance on Spotify very annoying. The Librespot GUI on RopieeXL does not allow to do that) + EQ my headphone (a bit more bass and treble).
 

somebodyelse

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I doubt you'll find either of those in alsamixer unless you start adding other things too, like adding alsaequal to the alsa config. Normalization really needs to be at the player level using metadata from the track or album - is there a librespot option that RoPieee isn't using?
 

Bernd

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I doubt you'll find either of those in alsamixer unless you start adding other things too, like adding alsaequal to the alsa config. Normalization really needs to be at the player level using metadata from the track or album - is there a librespot option that RoPieee isn't using?
Well, nothing much can be controlled - this is the interface for Librespot
ls.jpg
 

somebodyelse

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https://github.com/librespot-org/librespot/wiki/Options
librespot itself has come config options for normalization, so you may be able to mod RoPieeeXL to use those, or even present them in the web gui. If you can't do it yourself then ask in their forum - they might add it for you. The same might go for adding EQ options - I guess given that Roon has it built in at the server end it's not been an issue before XL appeared.
 

Bernd

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https://github.com/librespot-org/librespot/wiki/Options
librespot itself has come config options for normalization, so you may be able to mod RoPieeeXL to use those, or even present them in the web gui. If you can't do it yourself then ask in their forum - they might add it for you. The same might go for adding EQ options - I guess given that Roon has it built in at the server end it's not been an issue before XL appeared.

Hi, thanks for your reply. Indeed, ROON does that server side which is why you need quite powerful config to run the DSP option (interestingly this allows DSPing MQA streams without breaking it which seems to me a contradiction to the objective of MQA). However I have little hope that will get help from there side for anything connected with Spotify. I was already surprised to see Librespot as an option in RoopieeXL.
 

somebodyelse

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I'm not sure if Roon's DSP is inefficient, or if the powerful machine requirement is just covering themselves in case people try DSP on DSD in multiple rooms with different EQ. One of the CamillaDSP projects for LMS jokes about tasty looking CPU in such combinations while more 'normal' situations are MUCH less demanding.
It's certainly against one of the original claimed objectives of MQA, but do they still claim that, and is it any more believable than the original 'lossless' claim?
My understanding was that XL was for adding support for non-Roon sources, in which case adding EQ options for them seems within scope. I may be wrong - haven't used it or tried developing for it. Can't hurt to ask though.
 

Bernd

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I'm not sure if Roon's DSP is inefficient, or if the powerful machine requirement is just covering themselves in case people try DSP on DSD in multiple rooms with different EQ. One of the CamillaDSP projects for LMS jokes about tasty looking CPU in such combinations while more 'normal' situations are MUCH less demanding.
It's certainly against one of the original claimed objectives of MQA, but do they still claim that, and is it any more believable than the original 'lossless' claim?
My understanding was that XL was for adding support for non-Roon sources, in which case adding EQ options for them seems within scope. I may be wrong - haven't used it or tried developing for it. Can't hurt to ask though.
Tnx for your reply: I agree with you on the 'lossless' claim. Moreover I think, that MQA was/is trying to solve an issue that has basically disappeared: insufficient bandwith to stream highres audio files. In many countries you could stream in DSD/SACD quality these days - but then this is a proposition without a business case. I do not know how many subscribers ROON has but is a mere drop in the ocean of Spotify and the puddles of Tidal, Quobuz and Deezer.
 
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