USB audio transmission isn’t bit true

[beerandmusic]

8 minutes ago, esldude said:

I've seen nothing to indicate you'd recognize a professional comment when you read it. 

then do it for OTHERS....that or abstain from troll posts like the one you just made....i am surprised you have not been warned before.

[Summit]

5 hours ago, beerandmusic said:

SUMMARY:

Everything i believed starting this thread is EXACTLY the same as what i concluded....people tried to read into what i was saying, but did so incorrectly....

 

In Reading article in below link, IFI says EXACTLY what i was saying...that i am not convinced that errors will only cause a dropout, that i can understand that if an entire packet was dropped, you may hear a click or drop... but not if occasional bits....that i suspect distortion.....here they suggest exactly as i guessed....

 

https://www.audiocircle.com/index.php?topic=148763.0

 

EXCERPT FROM IFI  ==

Isochronous transfer mode uses error-checking but includes no re-transmission in case of Cyclic Redundancy Check (CRC) errors. Electrical noise on USB signals causes CRC errors and thus data loss, as does poor signal integrity.   In mild cases, this leads to audio signal distortions. In the worst cases, clicks and dropouts.

===

 

Note also from above excerpt, they also state that noise can causes errors and data loss...something else i said but that was rejected....I deduced both of these FACTS by logical reasoning...never read it before, and it went against everything that most people here have claimed......

 

When you get errors, and you will (more so if noise, interrupts, buffer settings, heavy processing, etc....many things can affect error rate) which leads to either distortion, interpolation (possibly incorrect), or dropouts (if too many errors and entire packet is dropped).  It is very feasible that you will have distortion (or unnatural music) and not even know it.... ..

 

None of these facts suggest one cannot have a good usb solution.  I do believe one can have a stable optimized USB solution, and that some DACS will do a better job than others in handling the error rate...

 

If re-transmission in case of CRC errors was a real problem, no one would use Isochronous USB. Of course if you don’t build devises and cables properly you may get some transmission problem. Also if you use a USB cable of bad quality or use a longer than approved length, yes drop outs and pops can occur.

 

In the same linked text you quoted from they also say: “In 2014, audiophile and technologist Fred Mak (known more commonly by ‘Fmak’ moniker) showed that with some combinations of cables and USB devices, asynchronous USB audio streaming can evidence disturbingly high levels of CRC errors.”

 

“Though his observations were under-appreciated, we at AMR can concur as we found in 2010 that in some cases, active USB cables were able to cut the USB audio error rate to zero. Using cables with a tight impedance specification also helped greatly to eliminate such errors; leading ultimately to the introduction of iFi USB audio improvement devices and cables.”

 

https://www.audiocircle.com/index.php?topic=148763.0

[yamamoto2002]

I use generic 6ft certified Hi-Speed USB cable and it is practically error-free at least on my audio setup.

[AudioDoctor]

5 hours ago, Summit said:

 

If re-transmission in case of CRC errors was a real problem, no one would use Isochronous USB. Of course if you don’t build devises and cables properly you may get some transmission problem. Also if you use a USB cable of bad quality or use a longer than approved length, yes drop outs and pops can occur.

 

In the same linked text you quoted from they also say: “In 2014, audiophile and technologist Fred Mak (known more commonly by ‘Fmak’ moniker) showed that with some combinations of cables and USB devices, asynchronous USB audio streaming can evidence disturbingly high levels of CRC errors.”

 

“Though his observations were under-appreciated, we at AMR can concur as we found in 2010 that in some cases, active USB cables were able to cut the USB audio error rate to zero. Using cables with a tight impedance specification also helped greatly to eliminate such errors; leading ultimately to the introduction of iFi USB audio improvement devices and cables.”

 

https://www.audiocircle.com/index.php?topic=148763.0

 

 

Another thing to keep in mind when reading this, they are trying to sell you something to fix the "errors" they are telling you exist.

[AudioDoctor]

14 hours ago, Ralf11 said:

Yours was an invalid response to my comment.

 

 

In other words...

 

you got a 0 when you expected a 1?

[beerandmusic]

1 hour ago, AudioDoctor said:

 

 

Another thing to keep in mind when reading this, they are trying to sell you something to fix the "errors" they are telling you exist.

everyone that has measured has found error rate, and even Mansr who isn't trying to sell anyything stated that even a single bit can wreak havoc on your system....again, depends on system as a whole, but usb is subject to noise issues that can cause crc errors and must be resolved for.

[beerandmusic]

6 hours ago, yamamoto2002 said:

I use generic 6ft certified Hi-Speed USB cable and it is practically error-free at least on my audio setup.

+1 

I know i would only use a standard usb cable....i never understand the people that suggest USB is ideal and buy a fancy cable (lol).

[wgscott]

Even a stopped watch is right twice a day.

[Sonicularity]

2 minutes ago, wgscott said:

Even a stopped watch is right twice a day.

 

Then that watch is right, and nobody can tell me that it is broken.  It works exactly as I suspected it would and unless a horologist can sway my already firmly established mind on the matter, I refuse to post further on the subject.

[PeterSt]

15 minutes ago, wgscott said:

Even a stopped watch is right twice a day.

 

One walking backwards even more.

[audiobomber]

@beerandmusic, why the fixation with isosynchronous USB? Aren't most audiophile DAC's asynchronous?

[AudioDoctor]

1 hour ago, beerandmusic said:

everyone that has measured has found error rate, and even Mansr who isn't trying to sell anyything stated that even a single bit can wreak havoc on your system....again, depends on system as a whole, but usb is subject to noise issues that can cause crc errors and must be resolved for.

 

It can wreak havoc people! HAVOC!!!!!!

 

Lets get NASA on this STAT!  DARPA too while we're at it, get our top people on solving this issue. We need less havoc wreaked on our stereo systems... Just this morning my stereo blew up after my USB caused an error, burned down my entire house, took my car, emptied my bank accounts, and left with my SO.

 

This is unacceptable.  Now I have to buy a new stereo.

[kumakuma]

1 hour ago, beerandmusic said:

even Mansr who isn't trying to sell anyything stated that even a single bit can wreak havoc on your system

 

When?

 

This doesn't sound like something @mansr would say.

[mansr]

1 minute ago, audiobomber said:

Why the fixation with isosynchronous USB? Aren't most audiophile DAC's asynchronous?

Firstly, it's called isochronous. This means a fixed bandwidth from host to DAC is reserved, ensuring that it isn't starved of data due to other device activity. Transfers are scheduled at regular intervals. Isochronous endpoints can have any of several synchronisation types defined by the USB spec:

 

Most DACs use an asynchronous sink coupled with an adaptive source (the host computer).

[Ralf11]

4 hours ago, AudioDoctor said:

 

 

In other words...

 

you got a 0 when you expected a 1?

 

my expectations are very low

 

hark back to your early coursework and recall that humans are just monkeys that write history...

[beerandmusic]

3 hours ago, kumakuma said:

 

When?

 

This doesn't sound like something @mansr would say.

you even provided me the links where MANSR was testing a fubar cable...besides this quote, he provided wav file and said buzzing and distortion also occurred besides skips...granted, he was using a fubar cable....

 

MANSR QUOTE>>>" When errors start showing up, it's as an occasional skip which is clearly audible. The thing is, as soon as a single bit is wrong, an entire packet is discarded, and this causes a huge error in the recovered data stream. "

 

But i don't entirely agree with the statement...., i agree with IFI that single bit errors can also cause distortion...and also don't think all dacs will drop the entire packet for a single bit error....more likely, if a packet is dropped you would hear a click/skip/dropout...but I also believe some DACS will interpolate and some will process even with errors...and clearly if it's just a single bit you likely would not even hear it....think many thousands of bits per second...you would not hear one bit...now if you have many crc errors and the dac doesn't drop the entire packet, you would have distortion....MANSR did state that he heard buzzing and distorted sound in one of his tests where there were many errors, so it sounded like in that thread, that he acknowledged that error rates can cause both distortion and dropouts....really depends on how the DAC manages the CRC errors.  Archimago also stated error rate can cause distortion in one of his blogs....again, i am not suggesting in an optimal normal setup, that this likely would occur....i am thinking it is more dependent on noise and computer interrupts.  Why else worry about things like running processes, buffer settings, and why would people suggest noise limiting cables and usb toys and reclockers etc...designed to minimize noise can help in some environments...it just depends on hardware, noise, buffer settings, computer interrupts, etc....many things can cause crc errors, but it has been proven by IFI that noise can impact CRC errors....and we all know now, that if there are errors, the packet will not be resent...the errors will be processed in one way or another by the dac.

[Superdad]

30 minutes ago, beerandmusic said:

But i don't entirely agree with the statement...., i agree with IFI that single bit errors can also cause distortion...and also don't think all dacs will drop the entire packet for a single bit error....more likely, if a packet is dropped you would hear a click/skip/dropout...but I also believe some DACS will interpolate and some will process even with errors...and clearly if it's just a single bit you likely would not even hear it....think many thousands of bits per second...you would not hear one bit...now if you have many crc errors and the dac doesn't drop the entire packet, you would have distortion....

 

B&M, this is your last warning: I am going to call the ellipsis police on you ...

I bet you might even receive more thoughtful responses if you would learn to capitalize a sentence, use a period, and start new paragraphs.  Everyone's mind is a messy place, please don't pour your stream of consciousness into ours.

[mansr]

1 hour ago, beerandmusic said:

you even provided me the links where MANSR was testing a fubar cable...besides this quote, he provided wav file and said buzzing and distortion also occurred besides skips...granted, he was using a fubar cable....

 

MANSR QUOTE>>>" When errors start showing up, it's as an occasional skip which is clearly audible. The thing is, as soon as a single bit is wrong, an entire packet is discarded, and this causes a huge error in the recovered data stream. "

 

But i don't entirely agree with the statement...., i agree with IFI that single bit errors can also cause distortion...and also don't think all dacs will drop the entire packet for a single bit error....more likely, if a packet is dropped you would hear a click/skip/dropout...but I also believe some DACS will interpolate and some will process even with errors...and clearly if it's just a single bit you likely would not even hear it....think many thousands of bits per second...you would not hear one bit...now if you have many crc errors and the dac doesn't drop the entire packet, you would have distortion....MANSR did state that he heard buzzing and distorted sound in one of his tests where there were many errors, so it sounded like in that thread, that he acknowledged that error rates can cause both distortion and dropouts....really depends on how the DAC manages the CRC errors.  Archimago also stated error rate can cause distortion in one of his blogs....again, i am not suggesting in an optimal normal setup, that this likely would occur....i am thinking it is more dependent on noise and computer interrupts.  Why else worry about things like running processes, buffer settings, and why would people suggest noise limiting cables and usb toys and reclockers etc...designed to minimize noise can help in some environments...it just depends on hardware, noise, buffer settings, computer interrupts, etc....many things can cause crc errors, but it has been proven by IFI that noise can impact CRC errors....and we all know now, that if there are errors, the packet will not be resent...the errors will be processed in one way or another by the dac.

This is just too funny.

[mansr]

29 minutes ago, Superdad said:

please don't pour your stream of consciousness into ours.

I think you mean maelstrom.

[beerandmusic]

usb 3.1 may resolve with inclusion of Hub buffering and prioritization rules which can result in packet reordering....

 

https://www.synopsys.com/designware-ip/technical-bulletin/guaranteed-isochronous-traffic.html

[beerandmusic]

from the well-tempered computer, something i just read and didn't know before, is that the isochronous transmission begins internal to computer before even transmitted out,

 

Isochronous transfer

When the computer sends the audio stream to an USB port, if first reads the data from the hard disk and caches blocks of the data in memory.

It is then spooled from memory to the output port in a continuous stream (Isochronous mode).

Frames are sent out every millisecond.
This happens whether there is any data in the frame or not.
The rate at which the frames go out is determined by a oscillator driving the USB bus. (noting here, can upgraded pc clock can make difference? )
This rate is independent of everything else going on in the PC.
In principle this guarantees a constant flow of the frames.
In practice the frames might not be filled properly with data because some program simply hogs the CPU or the PCI.
Anti virus polling the internet at high priority are a well known example.

 

Isochronous transfer can be done with three possible types of synchronization modes in the USB audio device.

[sandyk]

5 hours ago, mansr said:

Most DACs use an asynchronous sink coupled with an adaptive source (the host computer).

 

Most recent DACs use an asynchronous sink coupled with an adaptive source (the host computer) ?

[beerandmusic]

 

 

31 minutes ago, sandyk said:

 

Most recent DACs use an asynchronous sink coupled with an adaptive source (the host computer) ?

 

interesting read here...albeit dated 2012 (smile).

 

 

To qualify as an asynchronous DAC, ... the designer would throw away the source clock and rely only on the DAC’S internal clock. There are scarce few of these around.  scarce in 2012, how about now?  do all dacs "throw away source clock" and use dac's clock?

 

https://www.psaudio.com/pauls-posts/myth-asynchronous-dac/

 

I also read, but don't know if true or not, the question of if host(computer) transmittting in isochronus mode, it doesn't matter if dac is asynchronous or not....

 

Perhaps the driver would indicate if you use the DAC driver vs an os supplied driver?

[asdf1000]

8 minutes ago, beerandmusic said:

 

 

 

interesting read here...albeit dated 2012 (smile).

 

 

To qualify as an asynchronous DAC, ... the designer would throw away the source clock and rely only on the DAC’S internal clock. There are scarce few of these around.  scarce in 2012, how about now?  do all dacs "throw away source clock" and use dac's clock?

 

https://www.psaudio.com/pauls-posts/myth-asynchronous-dac/

 

I also read, but don't know if true or not, the question of if host(computer) transmittting in isochronus mode, it doesn't matter if dac is asynchronous or not....

 

Ted Smith was here on the forum for a short while and explained a bit here and some later posts:

 

https://www.computeraudiophile.com/forums/topic/19023-ps-audio-directstream-dac/?do=findComment&comment=300547

 

Don't bother tagging him here now - he's not here. You can reach him on the PS Audio forum though - he's very active over there.

[beerandmusic]

link below states

All audio data is transferred over isochronous transfers, but then goes on to discuss asynchronous..not sure how you can guarantee time and error free, but it seems we use "isochronus aysnchronous" with usb audio?

 

https://support.hifimediy.com/support/solutions/articles/8000007421-asynchronous-usb-audio-asynchronous-digital-to-analog-converters