So, no matter what explanation is being presented as to why package timing is irrelevant, you’ll always reject it based on your subjective impressions. What’s the point in asking over and over?
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You guys are so tough! I try to draw the audio-subjectivists out through the lighted portal at the end of the dark hall by building awareness on top of their own claims. Borrowing from conspiracy theory theorization, there are some cool ideas like “inoculation” and “disenchantment” that can be applied in little micro-laboratories like this:
I’m mostly on the disenchantment side of the programme, bringing up the cognitive dissonance of the claims of other actors (the Diretta team, for example) and their silence about clear evidence, for instance. Oh, and the inoculation I tried with Orch-OR quantum consciousness!
But, ultimately, there always seems to be incorrigible resilience based on subjective experience, I know, and it is certainly tiresome, especially after so much effort has been put into testing this stuff! 
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To question your senses when evidence doesn’t agree, even if that means your painstaking work may have been for naught, now that would be tough. Sticking with “but I hear differences” - not so much.
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Diretta claims (inasmuch as any meaning can be extracted from their whitepapers, which notoriously consist of meaningless technobabble and only meaningless technobabble) that the changes in network packet delivery that you have measured result in real, audible changes in DAC output. Never mind that their explanation contradicts all known laws of physics.
Well, we have @Marian here who had both measured the signal and did blind tests that had quite conclusively shown that just as expected, Diretta has no effect, either measured or audible. In other words, it does absolutely nothing.
If someone, based on a sighted comparison, thinks that it does have some effect, it is up to them to provide proof of that. And maybe some plausible explanation. Because Diretta for sure does not.
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In my system I hear changes in sound with some builds of roon and other music software. This is always volume leveled, no DSP and the same audio chains. I am unable to supply measurements for this but they are real to me and I guess that is all that matters. I am learning to refrain from posting these and just enjoy them. I have not tried Diretta yet but probably will as it may make a difference in my system and I like to tinker. There are enough users who hear an improvement so I am interested.
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Huh? That’s just a choice because it is in principle entirely impossible to know or prove, as the existence of a God would not have any known impact on anything we can observe.
I.e., this has absolutely nothing to do with whether something physical in our observable reality has an actual impact.
Feel free to believe without evidence that Diretta has an audible or measurable impact, but don’t present it as fact and don’t expect anyone to believe something just because you say so.
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Let’s recap where we are.
Marian put in a lot of work to test David Snyder’s RPi5 3 tier Diretta build finding:
- Noise levels measured out of the DAC were no different from his current streamer
- Sound quality was no better and perhaps worse than his current streamer, as supported by his sons
Stating Diretta claims are debunked
I have an issue with the debunked claim and offered a better sounding Diretta host configuration, which Marian declined. Ok. But claims of a system debunked without understanding how/why a system is configured, or what Diretta’s architecture is really doing, is pretty silly. Marian’s test is valid, but its a single data point. And I don’t argue his results.
I did make a lot of claims on how Diretta actually works, and I backed that up with concrete evidence in this post. It’s clearly not doing nothing and isn’t vaporware. The Diretta community isn’t hallucinating.
At this point no matter what I say on SQ, or my family and friends, will be accepted in this forum. But others see benefits and developing solutions on top of Diretta. Piero isn’t going to spend his time building these into Audiolinux unless there’s real value.
The last 6 months of Audiolinux updates are mostly new Diretta based solutions. To include:
Menu 509 Squeeze2Diretta update
Menu 506 Squeeze2Diretta
Menu 504 DIRETTA UPnP renderer update
Menu 502 DIRETTA UPnP renderer
I haven’t even made what I feel are controversial statements yet. What will really piss you all off is that when Diretta is optimally configured you will be able to dial-in the configuration to your DAC with the setting.inf dials: LatencyBuffer, InfoCycle, CycleTime/CycleMinTime, syncBufferCount, SingleMode, and Jumbo Frames. Each of these changes are impactful, but I don’t believe are measurable other than listening tests.
Here is my research. Have at it if you want to.
PCM and Low DSD tuning was extensively tested with my daughters, and the tuning guide reflects what we heard as the dials were changed. High DSD is currently being tested in the community, so the suggestions are best effort estimates and need user validation.
Marian tested a configuration that another user stated was clearly sounding better.
The second doesn’t follow from the first. It may be doing something (nobody really disputed that) but that doesn’t prove that what it’s doing makes a DAC sound better.
It will be if you run a test that is well designed, even if it is under real-life constraints, just like Marian‘s was.
This is a fallacy because we know for a fact that audiophile brands do lots of stuff for marketing reasons that has no effect.
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The entire premise is a logical fallacy, and all the reasoning at the top of the thread, even if true, does not make the conclusion true.
Moreover, the comment that it must be benficial because some hear a difference is non sequitur, that is, yet another fallacy.
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First, I understand what has been done and why, and what Diretta claims are. (As a matter of fact, I corrected the record on that.) But why is that a requirement? I measured what they claim they are improving: electrical noise on the streamer. And one certainly doesn’t need to take networking or signals and systems classes to listen critically.
The only one so far. I encourage everyone to do the same, with the same care to eliminate bias, so we can have multiple data points.
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One could not help but wonder why does not Diretta itself describe such a “better sounding” configuration. One would think it would be the very basic first step if they were trying to promote the… whatever Diretta is, based on some sound quality inmprovements.
We do have a few users here (I’d point at @Marian , or @ExUnoPlura in no particular order, and I would mention more but I am not allowed to mention more than two people 
) as ones having appropriate education and experience to know how systems are configured, how electronics work, and what Diretta is doing…
There’s a difference between “what does Diretta do for network transmission” (it does something, obviously) and “what does Diretta do for analogue output of a DAC” (which remains the same, and noone, starting with Diretta’s designers, had offered any plausible explanation as to why it should change at all).
As mentioned above, there are protocols for testing that that would be accepted anywhere, from here to ASR and beyond.
IIRC AudioLinux is a commercial product. Of course the developer would spend his time if it is bringing real value ($$$) to his bank account. So do people selling cable lifters, fuses, quantum dots, and magic crystals.
That’s just a circumspect way of saying “none of these actually does anything but I really want to believe and therefore I hear the difference.”
If any of these things did do anything, wouldn’t Diretta’s vendor (assuming there is anyone there who would even know what a “jumbo frame” or “latency” are) set them as defaults? Because they sound so much better.
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To be clear, are you claiming that significant, hearable changes are not measurable in principle?
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I’ve read your posts on what you did including what you measured. I’ve also followed the other relevant threads.
I don’t doubt that Diretta is composed of many lines of code that do things. I also don’t doubt that the impact of its work can be seen and measured in the places you’ve seen and measured it. What I don’t understand, though, is how you go from your measurements to the assertion that these things that it does have an impact on sound quality. This is an inference leap that isn’t derivable from the experiments.
This Diretta stuff is so simple to frame as an experiment. Doing the actual work might be hard, but the framing is simple.
- This is an experimental domain in which Diretta is the Independent Variable (IV) and Sound Quality is the Dependent Variable (DV)
- We want to know if changes to the IV result in changes to the DV - this is causality
- As with all experiments, we start by defining the “Null Hypotheses” and then experiment to see if it is disprovable
- The Null Hypothesis is “Diretta does not impact Sound Quality”
@Matthew_Arndt1 - when I read your first post in this thread, it appears that you are trying to disprove some other null hypothesis which is something more akin to “Diretta doesn’t do anything”. You’re measuring scheduling, packet arrival, buffers, etc. That’s fine and interesting, but they’re not the actual topic of interest.
The first, and only truly interesting thing, is to establish that Diretta impacts sound quality (or even just sound without the “quality” modifier) in some way. If we can’t start with that, then none of the rest matters or is interesting. The Diretta software might as well be factoring prime numbers or sequencing DNA or something because there’s not yet any evidence at all that it does anything interesting in the sound domain.
If you, or anyone, can establish that it actually does something to sound, then the rest of your experimental structures and strategies become super interesting! Incredibly interesting! This will be true because you’ll now be able to start to isolate and understand which aspects of Diretta actually have impact and what impact they have. It won’t be a magical, mysterious, metaphysical thing anymore and we’ll all be able to start having a fantastic discussion about whether it’s buffer fullness, CPU activity, power rail draw! Those will become the independent variables!
This entire Diretta conversation has been fairly bizarre to me because the Diretta marketeers claim physics and science as the foundation for its capabilities but eschew physics and science when asked if the thing actually does what it claims to do. “We use science to make this but we refuse to use science to measure it”. Does that seem strange? It does to me.
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With Async USB Audio, the only ‘corrective’ work the USB receiver inside of the DAC does is to determine what clock rate value it will send in it’s next message to the upstream host - to tell it how fast or slow to send upcoming frames, solely in order to ensure that the DAC side buffer neither underflows or overflows. And these messages are sent at a fixed rate of 125µs by the DAC no matter what - the same as the intended rate that the DAC hopes that the upstream host sends actual data in the other direction.
Even if the upstream Diretta endpoint is sending packets with perfect timing, the DAC will still calculate the required clock rate and send a message every 125µs to tell the endpoint to keep sending at that same rate.
Or to look at it the other way - even if upstream packets are sent in an unsteady fashion, there is no “increased interval activity near the conversion path” as you suggest.
If a frame is actually corrupt, or the buffer does actually underflow or overflow due to the upstream host not sending data at the right rate for long enough, there is nothing the DAC can do about it - and you will hear it as a dropout or dust pop. (While USB Audio does have CRC’s that can be used to validate frame integrity they are informational only and not correctible. That said, many tests have shown that corrupt frames are exceedingly rare with any properly spec’ed USB cable.)
You have to gone to great lengths to show that Diretta does change/improve the packet flow and timing within the endpoint itself, but unfortunately that does not impact the downstream DAC in the manner you propose above.
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Do I need to remind anyone that Ai generated posts are prohibited in this forum?
By all means use Ai to help formulate some ideas but posts should be in your own inimitable style 
Thank you for your cooperation.
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IMHO I think sometimes we forget why we like this hobby and that is listening to music. Chasing bits and bytes obsesively, well the question is it will change the experience of listenig MIles Davis? A switch does not know it’s carrying Miles Davis.
It sees packets.
A USB cable doesn’t know it’s “music.”
It sees a data stream.
Bits are bits.
Where the signal becomes fragile is not at Ethernet framing. It’s when:
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The DAC converts voltage
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The analog stage amplifies microvolts
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The speakers move air
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The room reflects and cancels energy
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Your brain reconstructs a soundstage
That’s the real battlefield.
In terms of audible impact, roughly:
Room acoustics
Speaker placement
Speaker quality
Listening position
Amplification matching
DAC analog stage
Power noise issues (if severe)
Transport protocol tuning at microsecond levels
And yet… 80% of forum energy goes into #8.
Why?
It’s measurable.
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It feels technical.
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It’s controllable.
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It gives the illusion of optimization.
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It avoids moving a sofa or adding treatment panels.
Acoustics is messy, physical, unsexy.
Packet timing graphs are clean and satisfying.
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That has zero impact on the analog output, at least when using USB, so it shouldn’t even be on the list.
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Seems to me that the endpoint to be measured is our brain. FMRI & EEG may help to determine whether changing anything in our systems, or the environment in which they operate, offer up any clues to music reproduction and what we perceive, at a conscious level, and maybe, on a comparative basis, how two people experience the same music under the same settings. And I’m sure there are scientists who are better equipped than I am to weigh in on the validity of anything I’ve asserted. Further down the rabbit hole we go…
I think it’s only a small number of users and the rest just reacts
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i was being ironic. sorry it did not came through.
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