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543
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Ultimate Audio Playback / Phasure NOS1 DAC / Re: USB Clock Upgrade My Experiences (so far)
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on: December 16, 2013, 04:47:20 pm
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Alain, if I only knew which "tests" you are referring to. What must I test ? Nothing goes wrong you know (disgregard my last post of course). All I know is that the lower processor frequency brings me the best sound.
Regards,
Peter
Sorry Peter, I was referring to the potential missing samples in relation with a slower CPU, but at least your answer tells me that you consider this unrelated... I thought of this because I have read recently that some people do not sense FLAC files to sound much different from WAV since they changed their PC for more powerful ones... Alain |
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544
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Ultimate Audio Playback / Phasure NOS1 DAC / Re: USB Clock Upgrade My Experiences (so far)
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on: December 16, 2013, 01:42:16 pm
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Small brainstorm - may lead to nothing : My PC runs at 750MHz. This is Hyperthreaded, thus 375MHz per core. Audio playback runs in one core. Thinking Redbook, 705600(sampling rate) x 2(ch) x 4(bytes) = 5,644,800 bytes need to be transferred per second. 375,000,000 / 5,644,800 = 66 cycles of the processor are available to do it all for each byte. It is my fault that only 375,000,000 are available for it and thus also that only 66 cpu cycles are available per byte. Uhm, that does not seem very much to me ! Let's say that I only need one line of C++ code to hand that one byte to the audio buffer (never mind what that is) and that it will not be wildly off to think that one of such a line takes 6 lines of machine code, then only 11 cycles (66/6) are left to process one line of machine code. Uh-oh. These 11 cycles should include wait cycles for the various transfers from memory. Next, the remainder of the work is about switching buffers, activate them and some more overhead. I already don't see it working ... On the other hand, when the "load" of the playback is related to the cpu usage (which shows maybe 2% for all the cores in total, but the one crucial core also showing "nothing"), then what to think of that ? That the percentage showed it not correct ? can be. Or that I make so huge mistakes in above math ? can also be but of course I don't see that. Point is a bit : I know why and how I created Q5=1 and how that hugely avoids unnecessary processor cycles needed by the OS itself, and how exactly that makes the L/R thing and more strange sound go away (btw still working on that). *If* this avoids missing samples (all of them ?) then I think that my 750MHz general processor frequency isn't all that much too low because normal speed would only be 4 times higher that implying 4 times less sample loss; it would be a total coincidence when that 3GHz suddenly could process all samples, plus that 5 years back it couldn't have existed. Let's stick to my math being wrong for now; seems more safe.  Peter, Have you done the same tests, this time with the CPU at its full speed ? And with the hyperthread off ? Regards, Alain |
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547
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Ultimate Audio Playback / Phasure NOS1 DAC / Re: USB Clock Upgrade My Experiences (so far)
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on: December 07, 2013, 01:55:22 pm
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Hi Nick,
Trying to read about the "master-slave" relation between two USB ports... Is it something that is established normally between the sender and the receiver in the PC USB port and the NOS1 USB port or is it something that has to be "programmed" first ? If so, I would have thought that the sender would be the master ? By that I mean the "A" type USB as the master and the "B" type USB as the receiver ?
And would this achieve what you, Paul, Cohen and Peter are talking about ?
Regards,
Alain
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552
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Re: Hyperthread with a i7 ?
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on: November 30, 2013, 06:48:35 pm
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Peter, since I always understood that by "convert", you meant from "something" format -> wav, I never was sure it was useful to have 12 cores... But of course, if it does not affect anything (SQ, consumption, temperature or else), I am fine with using it (HT)... Regards, Alain -17C this morning... Brrrrr  |
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553
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Ultimate Audio Playback / Playback Tweaks and Source related subjects / Hyperthread with a i7 ?
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on: November 30, 2013, 04:38:22 pm
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I have been using all my music in wav format since the beginning. I even convert flac files to wav when a downloaded file is only available in flac. I use Dbpoweramp. I never really questionned if that was a good thing of not, so there is no rational behind this.
I don't know why I suddenly ask about this, but for this specific situation, I wonder if using hyperthreading is necessary ?
Of course I can test this for myself (and I will), but I am quite sure I will not be able to perceive a thing audibly (it may be too subtle). Even so, I wonder if that could also reduce the consumption and reduce temperature, implying for better SQ ?
Alain
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554
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Ultimate Audio Playback / Your thoughts about the Sound Quality / Re: The strangest sound ever, or ? Q5= ...
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on: November 30, 2013, 03:48:31 pm
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Hi Peter,
While I cannot pretend I hear something odd happening, I suppose that if your processor frequency is very low and that errors are happening when some interruption is induced, maybe you should adjust the frequency to be a little higher ? Provided that an i7 is tuned to work normally at 3.2ghz, it provides a lot of headroom for reduced speed, but the "sweet spot" could be somewhere between what you have achieved and the nominal frequency ? Just a suggestion of course and without any pretention, as a few things are completely over my head...
Alain
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