If the output is digital does the player make any difference to the so Options

[db579]

I'm wondering whether if you had two media playing pieces of hardware outputting digital music would the quality of the device make any difference? For example say you had a cheap-to-mid range android phone or mp3 player playing a flac file and outputting over HDMI to a receiver, and a higher spec digital media player like say the Olive 06HD playing the same flac file output over HDMI to a receiver would you hear/should there theoretically even be any difference in audio quality?

Thanks

[xnor]

As I said, isochronous (adaptive) transfer can work perfectly fine.

[Arnold B. Kruege...]

As I said, isochronous (adaptive) transfer can work perfectly fine.

I would like to see a real-world reliable test that shows it working any way but fine.

All we seem to have is these anecdotes.

[xnor]

All we seem to have is these anecdotes.

So you think a lot of people, including me (on my old notebook anyway), imagine audio glitches like VERY ANNOYING clicks or drop-outs with USB DACs? Screenshots of DPC latency measurements that clearly show that the hardware isn't able to stream audio glitch-free are anecdotes too?

Just because you haven't seen it yourself doesn't mean it's not real.

This post has been edited by xnor: Aug 2 2012, 21:25

[saratoga]

All we seem to have is these anecdotes.

So you think a lot of people, including me (on my old notebook anyway), imagine audio glitches like VERY ANNOYING clicks or drop-outs with USB DACs?

That does not follow. I don't think anyone here doubts that audio drop outs can happen with buggy hardware. I've certainly seen data corruption from USB drivers for instance. Doesn't mean I think the MSC spec is broken.

Thats the problem with anecdotal reports about glitches. You don't know what caused it. Driver bug? Chipset errata? Problem with the USB spec? What conclusion can you safely draw when you don't know what happened?

[xnor]

What conclusion can you safely draw when you don't know what happened?

If a user that reported the problem reduces the DPC latency and the problems disappear then I draw the conclusion that most likely a too high DPC latency was the problem. Unfortunately, not all users can fix their hardware configuration / drivers so they end up returning the device and replacing it with an S/PDIF or Firewire or PCIe or async. USB interface which seem to make less problems. HDMI, as I said, I don't know.

On my old laptop, for example, disabling WLAN reduces the DPC latency considerably and gets rid of nasty spikes that caused drop-outs. Still not convinced?

This post has been edited by xnor: Aug 2 2012, 21:39

[Arnold B. Kruege...]

What conclusion can you safely draw when you don't know what happened?

If a user that reported the problem reduces the DPC latency and the problems disappear then I draw the conclusion that most likely a too high DPC latency was the problem. Unfortunately, not all users can fix their hardware configuration / drivers so they end up returning the device and replacing it with an S/PDIF or Firewire or PCIe or async. USB interface which seem to make less problems. HDMI, as I said, I don't know.

On my old laptop, for example, disabling WLAN reduces the DPC latency considerably and gets rid of nasty spikes that caused drop-outs. Still not convinced?

My old laptop and my new laptop run audio over USB just swell using a very basic interface - the Behringer UCA 202 with no parameter changes from defaults, and both or either WLAN or wired LAN active and in use.

There was a lot of discussion of asynch USB over at AVS a while back, and subtle SQ and jitter were the only issues raised. No advocate of Aysnch USB was able to proffer a DBT or any measurement that supported their claims. In short, each and every problem was perceived and subtle which is to say, probably imaginary. I'm not saying that Asynch can't be a problem solver, I'm saying that it is an effective solution that is in search of a real-world problem that is actually causing someone audible problems. OK, it finds a few such people. Next!

I think that we all know that measuring a problem or nailing it in a DBT are both slam dunks when the kind of problems you describe are active. Since this isn't happening, the basic problem must be pretty rare.

What I take away is that the problems you mention are rare, and when they arise they are due to pre-existing technical difficulties that are both far more global within the laptop, and/or also very much peculiar to the laptop sample where they are observed. Most people are interested in Asynch USB because they are led into it by people with commercial interests ar a desire to be opinion leaders, not because of any actual audible problems that they are experiencing. In many cases you can buy a whole new really pretty good laptop (or several!) for the price premium of the Asynch USB interface.

Also, it appears that adding Asynch mode to a USB audio interface may be just a matter of changing the firmware. It shouldn't be increasing the price of the equipment by 1,000% or 10,000% which it currently is doing.

The world is full of USB audio interfaces that served their owners very well without any asynch support at all. I can wait for it to become a standard feature, which might even take a few years.

[xnor]

My old laptop and my new laptop run audio over USB just swell using a very basic interface - the Behringer UCA 202 with no parameter changes from defaults, and both or either WLAN or wired LAN active and in use.

My new computer also runs fine (average DPC latency of 60 us). So what?

I think that we all know that measuring a problem or nailing it in a DBT are both slam dunks when the kind of problems you describe are active. Since this isn't happening, the basic problem must be pretty rare.

Right, it's so rare that pro audio manufacturers have articles on this problem.
For example: avid/m-audio kb
or NI kb
or echo audio support
or focusrite even has a video
...
or just search in their forums.

Yes, it absolutely MUST be a pretty rare problem.

What I take away is that the problems you mention are rare, and when they arise they are due to pre-existing technical difficulties that are both far more global within the laptop, and/or also very much peculiar to the laptop sample where they are observed.

These problems are not limited to laptops. In fact, for example, certain nvidia driver versions had horrible latency problems. So do/did other devices' drivers.

Most people are interested in Asynch USB because they are led into it by people with commercial interests ar a desire to be opinion leaders, not because of any actual audible problems that they are experiencing. In many cases you can buy a whole new really pretty good laptop (or several!) for the price premium of the Asynch USB interface.

Also, it appears that adding Asynch mode to a USB audio interface may be just a matter of changing the firmware. It shouldn't be increasing the price of the equipment by 1,000% or 10,000% which it currently is doing.

I don't know about the firmware but I agree with the other points you make. I'm not advocating to buy an async interface either. As you've said it's probably cheaper to get a better laptop or PC that will run flawlessly with the interface.

All I'm saying is that even if the output is digital the player (a computer in this case) can make a difference under certain circumstances. These circumstances are certainly not the rule but those problems do exist and I wouldn't say they are pretty rare.

This post has been edited by xnor: Aug 3 2012, 15:04

[Arnold B. Kruege...]

My old laptop and my new laptop run audio over USB just swell using a very basic interface - the Behringer UCA 202 with no parameter changes from defaults, and both or either WLAN or wired LAN active and in use.

My new computer also runs fine (average DPC latency of 60 us). So what?

The good news is that you then don't have a dog in this fight. ;-)

I think that we all know that measuring a problem or nailing it in a DBT are both slam dunks when the kind of problems you describe are active. Since this isn't happening, the basic problem must be pretty rare.

Right, it's so rare that pro audio manufacturers have articles on this problem.
For example: avid/m-audio kb

Mentions tics and pops which asynch I/O being not a perfect panacea, may not address. Does not recommend or even mention Asynch USB.

or NI kb

Ditto, no mention of asynch as a solution.

or echo audio support

Ditto, no mention of asynch as a solution.

or focusrite even has a video
...

Ditto, no mention of asynch as a solution.

or just search in their forums.

Yes, it absolutely MUST be a pretty rare problem.

What is the relevant "it". Is it clicks and pops (which will always be with us) or clicks and pops or just poo SQ that is going to be fixed with aynch USB.

My comments about rare were in the context of a discussion of asynch USB. If you try to make them far more general than I obviously intended you can go anywhere you want.


If it was really common people would be lining up to buy and no market stimulation would be required.

[xnor]

Mentions tics and pops which asynch I/O being not a perfect panacea, may not address.

How do you know that?

Does not recommend or even mention Asynch USB.

Right, any manufacturer should recommend that if their users have problems with their own hardware to buy a new interface with async. I/O. Preferably from a different manufacturer. Makes sense.

later you even posted:

I agree because I know of no traditional pro vendor audio interface who is active with asynch USB interfaces. By active I mean formally announced or delivered products.

Those articles mention DPC latency as being one source of the problem. You said those problems must be pretty rare. I disagreed and posted those links. That's all there is to it.

What is the relevant "it".

I was talking about DPC latency problems, which should be blatantly clear by now.

My comments about rare were in the context of a discussion of asynch USB.

What? So what rare problems in the context of async USB are you talking about then?
To me it seems you're trying to avoid the DPC latency issue now after you've seen that even manufacturers acknowledge it's a problem.

If it was really common people would be lining up to buy and no market stimulation would be required.

I see, 'pretty rare' turns into 'common'..

This post has been edited by xnor: Aug 3 2012, 17:21

[Arnold B. Kruege...]

Mentions tics and pops which asynch I/O being not a perfect panacea, may not address.

How do you know that?

Simple. The tics and pops come from data that is lost inside the PC. We've had these as long as we have had computer interfaces that were entirely internal to the PC, and long before USB or even SPDIF.

[xnor]

Simple. The tics and pops come from data that is lost inside the PC.

I don't understand what you mean by that. Do you have any details on such issues? I guess now we're really talking about pretty rare events.

[Arnold B. Kruege...]

Simple. The tics and pops come from data that is lost inside the PC.

I don't understand what you mean by that.

There's a lot more places to lose data in a computer than just a USB link. On paper, many look like they should be abundantly fast and never lose a sample. But in the real world, stuff breaks and other tasks interfere. Data gets lost and you have a click or a pop. I'm not going to teach a computer architecture class, but there's where the answers lie.