But it’s the same DAC converting the same bits, right? That should be a well-defined and repeatable process.
On the exact same device chain? Yes, that’s what I don’t understand.
That’s OK, doesn’t matter even tho you chopped my question off where it suited you.
I’ll leave this SQ discussion with a quote from the CTO: “Have you ever heard that sound that car stereos used to make when a GSM cell phone was about to ring?”
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Oh, so all a bit-perfect player needs to do is block GSM signals and whatever other interference there may happen to be. In software. Got it.
Especially over the years with increasing technological advancements there is far more than GSM (3G/4G/5G), WiFi in various versions / frequencies, …
So all that has an impact on various points in the audio chain like DAC, cables,…
Granted. But how do you explain that all those interferences affect one bit-perfect player more than another?
Well bit-perfect is just „one of the outcomes“ of the player but the way doing this is quite different from player to player. So as stated here the software architecture causes different involvement of hardware and also this has an impact on the overall output.
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I fail to understand how the player affects the asynchronous D/A conversion of the DAC, which uses its own buffer and its own clock, given that the same exact bits are present in the DAC’s buffer when needed.
If having a notebook power supply plugged in or not affects the sound of a connected DAC then it’s time to toss the DAC and buy a competently designed one.
There’s no excuse for PSU noise entering the analogue output stage of a DAC. That’s just bad design.
There are cheap DACs achieving ~120dB SINAD regardless of what supply you use to power them.
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I’d really appreciate an example of this phenomenon.
But we’re not talking about RF interference here are we? We’re specifically trying to understand how the software delivering a bit-perfect stream to a DAC can affect the DAC’s analogue output, unless of course the software is no longer delivering a bit-perfect stream or is causing clipping in the D/A conversion.
You cannot send the same bit-perfect stream in the same format to a DAC from two different sources and achieve a difference in the analogue output - that’s simply illogical.
Except, of course, if the DAC is so poorly designed that PSU noise etc. is able to reach the analogue output, but then that’s not related to software, is it?
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There are so many parameters to investigate when SQ differences appear:
- Jitter in the delivery chain.
- Up or downsampling.
- Power noise (can give dramatic differences)
- Something more easy, like difference in buffer size when outpouring the (bitperfect) stream via e.g. USB or optical out. Principle example: Roon uses 512, while Audirvana uses 1024. And for mysterious reasons, it generates a delta in SQ. Things like that.
It is an endless set of possibilities. Therefore, it can be wise to not rule out anything up front, but be humble and start in one end. If people hear a SQ difference between two so-claimed bit perfect streams, then they do, and it is interesting to find the cause.
And the top layer: Psycho acoustics. One needs to be scrupulously honest, not “trying” to find pros and cons that can defend your “belowed” setup, etc. That can be a very hard test!
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(While in this thread more focus on software, there is a running discussion focussing more on hardware: Innuos USB reclocking & HQ Player - #97 by Michael_Pauliks)
I personally don‘t consider Roon to be an identical device chain.
There is always a Core and RAAT in between in addition vs using the native software.
Since there are various similar posts / observations with different hardware and software configs, my personal root cause analysis probably would point more towards the one commonality we all have - i.e. Core and RAAT.
I had intended to do some testing in that direction (different Core to begin with), but have not found the time to do so yet.
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My experience testing audirvana with RME bit perfect wave test.
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Not sure what happened for you there but Audirvana on macOS passes 16bit and 24bit tests with my ADI-2.
On macOS , HQPlayer is the only software that passes 32bit test for me. There’s even a comment about this in the user manual btw.
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Not sure, tried it may times that was using 3.5, others reported the same issue.
I was using Win… Weird how mine passed 32bit? and Mac didn’t for you??
I gave up on Audirvana many moons ago.
Roon is in a different league of reliability, performance and user-ability.
I also heavily utilise DSP for crossovers and room correction, Roon is leagues ahead.
Not really weird. As I mentioned, there’s a note in the user manual about that.
So actually expected.
The 24bit one for Audirvana failing for you is definitely weird though. No problem for me.
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Cool 
I don’t use AudioV anymore.
Or the RME.
I use Roon and a Motu MK5 lite these days.
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No worries! Just thought I’d clarify since you brought up both AudioV and the RME 
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