USB audio transmission isn’t bit true

[mansr]

1 hour ago, OE333 said:

So why was the Isochronous USB mode chosen for Audio transmissions ?

The reason is that USB Audio was (and is) mainly used for Pro-Audio equipment (the few Computer Audiophiles do not count). In Pro Audio the main interest is to avoid any latency - so the input buffers needed for error correction (with several ms latency) are an absolute No-No.

Latency is one reason, guaranteed bandwidth another. With bulk mode, a data burst on another device might eat into the bandwidth and cause drop-outs of indefinite length. Isochronous mode reserves bandwidth upfront that can't be used by other devices.

[Ralf11]

What  USB mode would be the absolute best for Audio transmissions ?

[mansr]

1 minute ago, Ralf11 said:

What  USB mode would be the absolute best for Audio transmissions ?

Only bulk and isochronous are at all suitable. The remaining two transfer types, control and interrupt, are no good. Given that errors are very rare in practice, isochronous seems preferable.

[Superdad]

5 hours ago, mansr said:

Only bulk and isochronous are at all suitable.

 

Yep, and pretty much every DAC firm who tried putting out products using bulk mode eventually gave up and went to isochronous.  Just too much hassle to produce and maintain custom drivers for every OS.  The advantages to bulk mode simply are not that great.

[yamamoto2002]

On 5/2/2019 at 7:16 AM, Ralf11 said:

What  USB mode would be the absolute best for Audio transmissions ?

 

I read somewhere RME person tried interrupt transfer and found it does not deliver sufficient data rate for audio use.

[beerandmusic]

On 11/26/2018 at 3:10 PM, yamamoto2002 said:

If you have a digital input device, and your DAC have a digital output, you can test if the DAC accurately output data bits or occasionally output corrupted data, by yourself with WasapiBitmatchChecker. Connect DAC digital out to digital recorder input and perform loopback test...

 

Following screenshot shows 12 hours of PCM data is sent using my $60 USB audio device and every output bits are correctly received by a PCM digital recording device. This test takes 12 hours to finish

 

USB specification says, in the worst case 1 bit in 1000 000 000 000 bit may be corrupted.

 

 

 

How about a multi-use windows pc and playing high speed dsd with a noisy power supply?  Do you have a way to capture that? 

[sandyk]

34 minutes ago, beerandmusic said:

 

How about a multi-use windows pc and playing high speed dsd with a noisy power supply?  Do you have a way to capture that? 

 

 Nobody here in recent  threads, including this one https://audiophilestyle.com/forums/topic/49648-lush2-share-your-configuration-experiences/or here https://audiophilestyle.com/forums/topic/59448-is-usb-straight-from-a-mac-computer-to-a-dac-really-that-bad/page/2/#comments #31. is suggesting that the Data is being corrupted and is the reason for perceived audible differences between USB cables etc.

 

USB Audio as stated elsewhere is normally error free provided that compliant USB cables are used  

 

[beerandmusic]

19 minutes ago, sandyk said:

 

 Nobody here in recent  threads is suggesting that the Data is being corrupted even when using different S/W players,

or here https://audiophilestyle.com/forums/topic/59448-is-usb-straight-from-a-mac-computer-to-a-dac-really-that-bad/page/2/#comments #31.

 

 

LETS START HERE:::

I want to know in this chain:::

 

regular use windows pc playing a 44.1K wav file using a Schiit unison mb dac will sound the same as

specialized windows pc wiht LPS playing same 44.1k wav file using same player and same dac

 

Most people i believe will say no, the one with quieter power supply will sound better.

 

I want to understand the logic behind that?

 

Do people agree the bits are received the same?  That it is just the noisy pc that causes a problem?

If the dac recieves the bits with 100% accuracy, and the unison isolates the 5v reference and reclocks the 100% accurate bits, then what would be the reasoning why one would sound better?

 

[sandyk]

2 minutes ago, beerandmusic said:

 

Most people i believe will say no, the one with quieter power supply will sound better.

 

I want to understand the logic behind that?

 

 The best way to help understand that , is to be first able to hear differences between things such as a generic couple of meters long Printer cable and a specialised USB cable such as the Lush cable from Peter.

 There are also likely to be technical explanations as well as measurements in Peter's thread that I mentioned.

[beerandmusic]

13 minutes ago, sandyk said:

 

 The best way to help understand that , is to be first able to hear differences between things such as a generic couple of meters long Printer cable and a specialised USB cable such as the Lush cable from Peter.

 There are also likely to be technical explanations as well as measurements in Peter's thread that I mentioned.

 

audio engineering cannot be that difficult...

 

you are sending

A) 5v reference voltage

B) digital music (does everybody agree or NOT, that the receiving dac gets this data accurately)

C) noise

 

In the past, everyone that spoke up would say that the digital music received is so accurate that it may drop one bit every 24hrs or something along those lines.

 

My thinking, is that if the dac does indeed recieve it's data with near perfect accuracy, and you isolate the 5v reference voltage and "reclock" the "perfect bits" with your own engineering circuit, then it should NOT make any difference how quiet ones pc is or not??

 

If that is not logical thinking, I just want to know the reasoning.

 

My thinking is that, if that is not logical thinking, then the only thing that would make sense is that

A) the bits are not received nearly as perfect as people suggest

B) audio engineers still have not figured out a "good design"

C) noise is not only not being isolated properly, but it corrupts the music data before input to the conversion circuitry.

D) noise is not being isolated properly and it affects the conversion circuitry

E) subjective minds inaccurately believe the two systems sound differently.

 

 

 

[sandyk]

Try also reading the attached, complete with measurements and his subjective reports

https://www.computeraudiophile.com/forums/topic/24275-ac-filtering-grounding-boxes-linear-psu-and-balanced-power/?page=68

 

[beerandmusic]

9 minutes ago, sandyk said:

Try also reading the attached from Larry, complete with measurements and his subjective reports

https://www.computeraudiophile.com/forums/topic/24275-ac-filtering-grounding-boxes-linear-psu-and-balanced-power/?page=68

 

without reading through a 73 page thread, it seems that it basically states that some usb's are noisier than others.

 

I do not disregard that.

 

not arguing one is noisier than the other, that is a "GIVEN"...question is, how does that noise affect the play, and have recent generation of dacs been designed to address this issue... (e.g. unison, isolating 5v reference and reclocking internally without a toy).

 

I stated probably 3+ years ago, that I believed that usb toys should not be needed, that the dac design should be sufficient in itself to address anything that usb sends it.

 

Clearly dacs are getting better, question is, are they "good enough" without a toy.

[sandyk]

3 minutes ago, beerandmusic said:

without reading through a 73 page thread, it seems that it basically states that some usb's are noisier than others

 

You don't need to. Just have a good read of page 68 that I quoted. There are incredible differences being measured there,

[beerandmusic]

 

Here is another sample track i use for critical listening.  I have it in both .wav and dsd256.

THere is an "extremely faint" musical instrument in the right speaker, that used to not be so apparent with an old dac.

Today, i can hear it both with a schiit mb w/unison and in the dsd file played from a thumbdrive as well as dsd via dlna but not from a dragonfly...my thinking is that

4 minutes ago, sandyk said:

 

You don't need to. Just have a good read of page 68 that I quoted. There are incredible differences being measured there,

 

I will read it now, but again, i do not doubt there are incredible differences measured regarding noise...but do they mention difference in SQ and what hardware they are using to listen for differences?

 

[beerandmusic]

40 minutes ago, sandyk said:

 

You don't need to. Just have a good read of page 68 that I quoted. There are incredible differences being measured there,

Ok i read it through.  There really wasn't any mention that i noticed that spoke to how the noisy usb affects the music....if it affects the music bits accuracy, or if the noise interferes with dacs circuitry.  It also didn't mention what dac he used or if it had galvanic isolation or reclocking circuitry...so my questions remain the same. 

 

The part of the page that most rang my bell to what i am speaking is:

 

MARCE>>Again though, one would have thought that the DAC input should have filtering on the supply if it is designed to be USB powered.

 

It is still my contention that the USB DAC design should compensate for any noise...and it is likely that if schiit's unison (with 5v reference isolation, galvanic isolation, and reclocking doesn't do the trick, then there are dacs that do....that thread was from 3 years ago, and galvanic isolation, reclocking, and LPS's with dacs are becoming more prominent. (i have my eyes on the gustard A18 coming soon ).

 

Just out of curiosity, i see you have a lot of custom gear, but what player do you use and to you play direct to usb out or do you use endpoint to a dac?

 

My ultimate goal is to have a general use pc that I can use its usb for simpicity purposes...if that means buying a better dac, or a LPS, i would be willing to do that, i just don't want to run custom audio software or use an endpoint, or do dlna anymore...i can always do that if i want for critical listening, but i just want a general use pc that i do all my other windows stuff on to also play my music for every day to day stuff.

 

I strongly believe that a DAC should be able to be built to compensate for any noisy usb.

 

 

 

 

[beerandmusic]

 

OK, I have found that I can actually hear "MORE MUSIC" using a schiit mb with unison.

 

It may not be a fair test as the only other usb dac i have currently is a dragonfly (i have probably had 15 different dacs over time and usually a few different ones at the same time, but i sold them all off awhile back ago)...anyway, my only comparison now is the dragonfly and i actually can hear a LOT more music from the schiit with unison.....

 

I don't know if it is due to noise isolation, reclocking or what, but I can hear more music.

Anyway, i think i can be "content" with using this as my every day windows computer with the schiit dac with unison.

 

I still have native dsd via dlna when i want it, but i just wanted something more convenient for every day.

 

Here is the test file...my source is DSD but have to set it to downsample to 192K for the schiit...but it sounds as good (or nearly as good) as DSD via DLNA.

 

With dragonfly, it literally is missing a lot of music that i can plainly hear with the schiit.

 

[sandyk]

15 minutes ago, beerandmusic said:

Just out of curiosity, i see you have a lot of custom gear, but what player do you use and to you play direct to usb out or do you use endpoint to a dac?

 

 For PC use I use Coax SPDIF Out from an Asus Xonar D2X Soundcard into a highly modified X-DAC V3 using JRiver 26 playing from System Memory then a DIY Class A HA with ATH M70x headphones .

  I only use USB for saving files to USB memory for either direct play, or plugging the USB memory into an Oppo 103 into my main system.

 I tried USB Out via a USB cable but the results were poorer with both A and V compared with I could get using the USB memory directly plugged in to the Oppo. Likewise, the results were mediocre when ripping using an external Samsung USB powered writer compared with using an internal BluRay LG GGW H20L with further improved internal  +12V and +5V power.( It was designed by our member al.fe)

  

[beerandmusic]

2 minutes ago, sandyk said:

 

 For PC use I use Coax SPDIF Out from an Asus Xonar D2X Soundcard into a highly modified X-DAC V3 using JRiver 26 playing from System Memory then a DIY Class A HA with ATH M70x headphones .

  I only use USB for saving files to USB memory for either direct play, or plugging the USB memory into an Oppo 103 into my main system.

 I tried USB Out via a USB cable but the results were poorer with both A and V compared with I could get using the USB memory directly plugged in to the Oppo. Likewise, the results were mediocre when ripping using an external Samsung USB powered writer compared with using an internal BluRay LG GGW H20L with further improved internal  +12V and +5V power.( It was designed by our member al.fe)

  

Funny...very similar to me.

Using jriver 26 (no special settings though)...i always got better results plugging usb stick into SR6013 (i have used many other usb stick methods in past as well (sony bluray players, marantz cd players) and almost always sounded as good or better than any dac including a gungnir multibit and many dsd flavored dacs.  The unison sounds very good...i think best dac i have had yet, even though it is only a bifrost mb....i think the bifrost mb w/unison may sound better than the gungnir w/gen5, but dont have both to a/b.  I do think this unison is a worthwhile upgrade, and I think my chase is over for awhile, but I will likely buy the gustard a18 when it comes out for comparison purposes to dsd via dlna.

 

[sandyk]

1 hour ago, beerandmusic said:

Using jriver 26 (no special settings though)…

  Have you tried doing this ?

[beerandmusic]

12 hours ago, sandyk said:

  Have you tried doing this ?

thanks, i will check the box...can't hurt!

[sandyk]

1 hour ago, beerandmusic said:

thanks, i will check the box...can't hurt!

 

If you play a track from a USB memory stick, unplug it part way through the track and the track should still keep playing.

[beerandmusic]

17 minutes ago, sandyk said:

 

If you play a track from a USB memory stick, unplug it part way through the track and the track should still keep playing.

both sounded good..i didn't notice any audible difference at initial testing...but will leave it checked..i think I understand the concept. which is why i agree it could only help...thanks.  (for most part i play from ssd).

[sandyk]

24 minutes ago, beerandmusic said:

both sounded good..i didn't notice any audible difference at initial testing...but will leave it checked..i think I understand the concept. which is why i agree it could only help...thanks.  (for most part i play from ssd).

 Try seeing if you can now hear any differences between the same high quality track saved to both SSD/HDD and a USB memory stick.

 If your playback system is high enough resolution you should be able to hear small differences. Some members even claim to be able to hear differences with memory playback when using different types of RAM ! 

[Superdad]

16 hours ago, beerandmusic said:

audio engineering cannot be that difficult...

 

Wow. Just wow. 

[beerandmusic]

7 minutes ago, Superdad said:

 

Wow. Just wow. 

was said in jest....figured someone would get a kick out of it....you must admit other technologies seem to have come a lot further....think of where we were without the internet or mass storage not that many years ago....and we can put a man in space, or cause nuclear holocaust....but we can't figure out how to isolate noise from usb audio with anything but subjectivity....amazing.