#GregD, that was an excellent call!
Indeed there was a tiny, tiny clipping going on. Needed 3 dB extra headroom to avoid all clipping. All perfect now, thanks!
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Fantastic - great you got it sorted.
Hi Frank. I fully agree on that. Glad to hear more people having the same observation.
Bits are not bits. I whish I could explain/ understand.
But you are right. Every technical thougts are welcome.
Rgrds jan
Every computer savvy person says bits are bits⌠That might be true in normal Files which are not time sensitive. Music is a âstreamâ with a clock and DACs that are really sensitive to noise as well. Those will kill quality of sound. The better your system is, the more you will notice the effects of these things. Most users of Roon have higher end setups with such DACs and connections that will be sensitive to external things. Remember streaming is converting data on the fly, it does not have time to assemble things and pause while it does it etcâŚwhich is what email and file transmit does with normal computer work. Its just not the same.
I saw a very cool test someone did on USB wires. He had a music file where he made a mirror image. When played at same time they canceled each other out and had ZERO sound. When he played the normal file over a usb cable at same time with source of mirror you could hear very light things⌠it was not a true mirror any more. The cable effected the sound. Diff. cables had different levels of sound. ie the better cable where the power was not near the tx/rx wires had better results. This was repeatable. Interesting enough repeating with the same cable yielded diff. results each time. They were all very very close to each other, but not exactly the same. I wish I had the link to the video. Sorry.
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We all wish you had the link to the video, Brian. I have a hard time imagining what this even means. What is the mirror image of a music file? How do you play two files at once?
found it. it was a while back but found the channel and then looked at his videos.
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If i understand the test correctly, heâs doing a D-A converion (in the TT2) and then an A-D conversion (in the Scarlett) and comparing the result with the original digital stream. When he finds a difference, for example at about 18 minutes in, he asserts that this is evidence that the transmission in the digital domain is not repeatably bit perfect.
That seems to me to be the wrong conclusion: the result shows that the complete experimental technique including the file time-alignment, digital transmission and D-A-D conversion is not repeatably âbit perfectâ - which is not particularly surprising, at least qualitatively - but it doesnât tell you where the imperfections occur.
In short, Iâd suggest his experiment doesnât demonstrate what he claims it does.
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But you also cannot prove if the difference was from the d2a side of the DAC or the a2d side of the capture I guess which is the problematic side of an experiment like this.
I did a similar experiment to this playing the same file on my system from local usb stick stuck in the streamer, over Wi-Fi and over Wired as others said it made a difference and usb playback was superior. I found no differences at all between. Did the same sum and difference tests and they cancelled each other out completely which means they where the same when I aligned them to be in sync. This could have been luck or my a2d devid was having a good day.
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Yeah its not the best, but its the same thing done over and over. When done twice on the same cable, the diff was super small. Which means the D/A and A/D are the same each time. But what explains why different cables have much more diff. than others? its not a perfect experiment but there are differences. This experiment would not be perfect any time, but shouldnt each one have the a similar error %? Multiple runs of each cable have a very small error %, but when compared they have much different results. Shows something is different.
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Well, I fear this is going way off topic. (Perhaps the mods might want to move this to a new thread.)
I agree that itâs unlikely that the differences arise from the D-A-D conversion. For a start, I doubt they would be as repeatable, and secondly I guess they would be orders of magnitude smaller than whatâs observed.
My bet is on the experimental technique itself introducing the differences. As is pointed out in one of the comments, if he manually time-aligned samples to make the waveforms for different tests âline upâ that could introduce systematic differences which are repeatable over multiple runs.
Actually I donât think he explained the experimental technique in enough detail to decide whether that - or indeed something else - could be the source of the differences.
Overall, I find the conclusion of this video hard to accept because he has assumed his results prove the (first) hypothesis he started with - that digital audio transmission over different cables can result in differences in sound. He has not considered (enough) other possible causes for his results, and has not tried to falsify these alternative explanations.
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Just wanted to share that after trying out various room correction tools I finally got the very best results with https://focusfidelity.com/
And itâs working perfectly with convolution / DSP in Roon. Anyone also using it?
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I use that with great results.
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Ah amazing to here! I wish I had known this tool earlier - would have saved me a very big amount of time dealing with REW and other tools 
Yeah it was so easy. Worth the money I paid over free REW. You can see the hump at 100-300hz that it fixed. Sounds so much better.
Did you find it lowered the volume quite a bit when compared to when DSP is off?
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They need to drop the level to make sure there is sufficient headroom to do the eq boosts without clipping.
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Oh that makes sense. Thanks.
Yes thatâs a necessity applied by all room correction systems. I am glad that Focus Fidelity Designer immediately made a huge difference / improvement over everything else I used before.
And looking back I wish I had spent 15min of my life sooner with it rather than changing various hardware components in my setup etc. that just made so little difference compared to this.
Especially interesting in Roon when after a few days you easily can compare by switching DSP off/on in the ROON app and you canât imagine ever switching back.
Hi Everyone, reduced volume with the room correction filters engaged is normal and as GregD mentioned is required to avoid digital clipping.
It is discussed in the Focus Fidelity user manual on page 28 https://www.focusfidelity.com/FFDManual.pdf (version 1.11 of the manual referenced here).
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Okay, so I just found this switch (it was in the âonâ condition) and now I am curious. Can someone tell me what this MEANS? How does this function when using DSP settings? Iâm not seeing anything in Roon KBâŚ
It means that any changes you make to the DSP settings will be applied immediately.
If the switch is off then you have to click the âapplyâ button to add the changes.
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