Bit perfect audio article

[Cosmik]

What Blum repeated for added emphasis , as this needed to be done

Audio is a low-bit application in this world where 10 GB Ethernet is commonplace. We need to keep this in mind. I am seeing Ethernet INterfaces making in-road in Audio (Pro Audio anyway with Ravenna and Dante) I like the idea, Iwoudl like to se more Ethernet DACs in our rank, much easier to interface. An Ethernet switch to drop on the network and send the signal anywhere you want with no fuss... Sound becomes even better (ot the bits more perfect ) if you use one of these Audioquest cables and if you have to ask for the price ...

Indeed. It is the obsession with the exact mechanism by which those bits get from A to B that mystifies me. Surely, fundamentally it is one of the most boring subjects ever!

Unidirectional links are less good than bidirectional links because they, undeniably, introduce an 'analogue' element into the system (theoretical rather than audible). But for home audio we don't have to use them.

If a bidirectional link has error correction and retries, then fine. If those facilities have been "turned off" for reasons which are now no longer relevant, then some standards committee somewhere should be looking into turning them back on. But if the link can't have those facilities, then all we need to do is ensure that there are no electrical problems corrupting the bits being transmitted, just as we would expect no errors in an S/PDIF link, or a track between chips on a PCB.

 

[Jinjuku]

What Blum repeated for added emphasis , as this needed to be done

Audio is a low-bit application in this world where 10 GB Ethernet is commonplace. We need to keep this in mind. I am seeing Ethernet Interfaces making in-road in Audio (Pro Audio anyway with Ravenna and Dante) I like the idea. Would like to see more Ethernet DACs in our rank, much easier to interface. An Ethernet switch to drop on the network and send the signal anywhere you want with no fuss... Sound becomes even better (or the bits more perfect ) if you use one of these Audioquest cables and if you have to ask for the price ...

Interesting tidbit about AQ and the cabling they terminate with the TeleGaernter industrial RJ45's: Those terminations make getting NeXT (Near end Cross Talk) into spec vs molded 8p8c RJ45 harder.

I had Lee Hutchinson of ArsTechnica send a Vodka RJE to Blue Jeans Cable for analysis on their Fluke certification tool. I correctly predicted it's NeXT would be worse than my $12 BJC 6a cables. All for the William Lowe price of $350.

 

[iridium]

Interesting tidbit about AQ and the cabling they terminate with the TeleGaernter industrial RJ45's: Those terminations make getting NeXT (Near end Cross Talk) into spec vs molded 8p8c RJ45 harder.

I had Lee Hutchinson of ArsTechnica send a Vodka RJE to Blue Jeans Cable for analysis on their Fluke certification tool. I correctly predicted it's NeXT would be worse than my $12 BJC 6a cables. All for the William Lowe price of $350.

Thank you for the tidbit.
I purchase some raw cable from their division: rawcable.com.
Excellent group.

iridium.

 

[FrantzM]

Interesting tidbit about AQ and the cabling they terminate with the TeleGaernter industrial RJ45's: Those terminations make getting NeXT (Near end Cross Talk) into spec vs molded 8p8c RJ45 harder.

I had Lee Hutchinson of ArsTechnica send a Vodka RJE to Blue Jeans Cable for analysis on their Fluke certification tool. I correctly predicted it's NeXT would be worse than my $12 BJC 6a cables. All for the William Lowe price of $350.

Yes but you didn't test their Best Ethernet Cable which cost $5500...

NO TYPO People! This Patch cable with a pair of RJ-45 cost Five Thousands Five Hundreds US Dollars on Audioadvisor.
AudioQuest Diamond RJ/E Ethernet Cable

It took me a while to digest the price. . Disbelief did set in and refused to acknowledge what my eyes told me I was reading. I had to google hard to verify such a blatant display of spitting in your face.

 

[Thomas savage]

Yes but you didn't test their Best Ethernet Cable which cost $5500...

NO TYPO People! This Patch cable with a pair of RJ-45 cost Five Thousands Five Hundreds US Dollars on Audioadvisor.
AudioQuest Diamond RJ/E Ethernet Cable

It took me a while to digest the price. . Disbelief did set in and refused to acknowledge what my eyes told me I was reading. I had to google hard to verify such a blatant display of spitting in your face.

That's the cost of having ALL the 1s n 0s arriving in the right order and at the right time, you can hear the difference.. Ears don't lie!

 

[Sal1950]

That's the cost of having ALL the 1s n 0s arriving in the right order and at the right time, you can hear the difference.. Ears don't lie!

Have they done a demo video on that yet?
The HDMI one proved their worth.

 

[wyup]

Given all of this, what is the worry about lack of error correction again? What are you losing that you hope to fix?


Of course it is real-time. At every sample period you better have a piece of data to feed the DAC or it starves and you get distortion. You have no option for flow control of the DAC (silicon). It is by definition a real-time system. Fact that it runs slower than the link doesn't make it non-real-time.

As I said, adding error retransmission makes things hard. Today USB implementations are simple. If you add error retransmission, they no longer are. You would need a complicated state machine or likely a microprocessor to handle such retransmission and much more buffering to keep things around to retransmit. TCP/IP does that for networking but that requires a host processor. All else being equal, we want to keep the interface logic simple and hence quiet.

Now, if we could demonstrate that erroneous data transfers are real and frequent problem, sure, we could address them. But they are. You say that users don't have such instruments or ears but designers do. Yet they have not documented such problems either. People who are concerned can use Ethernet interface and DACs. I personally think that is a poor trade off unless you need the much longer distances Ethernet can travel.

USB is not a data transmission protocol designed for real time audio and because of factors that affect reliability there should be some sort of error correction or data check.
There are documented factors within usb such as electromagnetic interference from the computer or the environment, inductance from power rails in the cable, ground loop interference, impedance mismatch or simply bad clock from the host signal. All these factors do degrade the signal, can make data reconstruction difficult and cause errors in reception, if you can measure this.
Today the processing load and memory needed for any error-check protocol from both sides is insignificant and 480Mbps is more than enough. There is no excuse not to have it. USB data already has some sort of error check, to my knowledge. HDMI has it aswell (Reed Solomon).

USB dacs have complex usb receivers, it wouldn't add for an additional error check.

Amir has done audio tests with USB cables, ground isolators, filters, maybe he could test transmission errors in some way.

Finally, maybe I'm wrong but I think there could be some sort of input clock accuracy independece from the signal, like Ethernet. Just a big enough memory buffer say for a second, data-check with re-send possibility, sample rate info and you reconstruct the whole second and clock it in the dac for d/a conversion.

 

[mansr]

Uh-huh