JPLAY Responds: An Open Letter

[jkeny]

Where is any measurement to show similar noise reduction and isolation? From the descriptions provided, Jplay is actually increasing CPU load by using short buffers. So even the theory doesn't support what you say.

I'm just replying to Barrows conjecture about the only possible way he envisages that Jplay could operate!
Did you download & listen to it or just want to continue to argue the technicalities, as you see them?

 

[amirm]

I'm just replying to Barrows conjecture about the only possible way he envisages that Jplay could operate!

He stated the engineering of how products are designed. that is not conjecture. The only conjecture was yours that changing software players equates electrical isolation. Since there is no data to back that, looks like we are done with that argument.

Did you download & listen to it or just want to continue to argue the technicalities, as you see them?

Again, you made the argument. I simply asked if you had data to back it. If you don't want me to ask you such technicalities, don't propose them.

And no, I have not played with it as it is not a priority for me. Nor a curiosity. All the data I needed is actually in front me: neither its developer or its #1 champion can propose a theory as to why it would improve anything, or any data that shows the same. This is solid data in itself. If you had a theory, and you spent your own time as much as you are asking me to spend to show its efficacy, then we could have something to pursue. But we don't.

 

[jkeny]

Really, Amir, your open-mindedness is showing, I'm afraid.

If you are not willing to or not interested in trying this for yourself, why are you bothered posting on this thread - just for arguments?

 

[barrows]

So if a €100 Jplay software does as good as these expensive devices with regard to noise isolation, are you complaining?
Yes, the noise "issue" was the one you raised & I was speaking of. So, as I asked have you tried one of these DAcs that you have listed? What is your experience with it's isolation characteristics?

Like mentioned, I use a custom linux based server (and I am in the process of getting a new one built with full battery power), so trying jplay is not an option for me, and my software is already optimized for audio playback only. If one must use a bloated swiss army knife software like windows, I can see how reducing CPU load, by shutting down unnecessary services could, in some systems, improve sound.
I use DIY DACs. Currently I am using an ABC USB interface, which does provide isolation in the manner I explained, except, I cannot be sure that it also re-aligns the data with the masterclock right before output (as it "should"). I have a new USB receiver in the works which will work exactly as explained, and will also include better oscillators, but this is a ways off still. Every effort I have made to reduce system noise pollution from the server has resulted in incremental improvements, this is not surprising considering how much more noise is produced by a MoBo/hard drive disc combo in comparison with typical audio components.
Software cannot provide noise isolation, only, perhaps (and this has not been established) noise reduction. I suspect actually isolating the ground of the master clocks/DAC from the computer is really what is necessary for the best performance (jitter wise, and to avoid IM problems in the DAC output stage). but do not have measurements to prove this. When I added the ground isolated ABC USB interface things did take a definite step up.

amirm: If a software add on such results in a significant drop in CPU activity, and the inactivity of a lot of normally running processes, and the resultant decrease in power consumption, is it not likely that reduced noise (both airborne RF products and electrical noise both shared on grounds, and injected back into the mains, assuming and AC powered server/computer) will be the result? I really do not believe any of these SW programs magically "improve" the data, but with as many anecdotal reports of improvement as there are, perhaps noise reduction is the only factor involved.
If jplay increases CPU activity, then its use is contrary to my experience.

 

[jkeny]

OK, barrows, so you are talking about what you expect will be the result when you chase down this USB receiver that works "exactly as explained". Maybe then you will do some experiments about what upstream changes can/cannot be heard. According to you there should be no possibility of upstream changes having any effect on the electronics on the "clean" side of the isolator. Will be interested in your results if you come back & post them here.

Interestingly, John Swenson says he has done this configuration & the DAC was not immune to PS change on the PC but WAS immune to USB cable changes

 

[barrows]

OK, barrows, so you are talking about what you expect will be the result when you chase down this USB receiver that works "exactly as explained". Maybe then you will do some experiments about what upstream changes can/cannot be heard. According to you there should be no possibility of upstream changes having any effect on the electronics on the "clean" side of the isolator. Will be interested in your results if you come back & post them here.

Interestingly, John Swenson says he has done this configuration & the DAC was not immune to PS change on the PC but WAS immune to USB cable changes

No, not at all. I was discussing the approach which is technically correct, and as I mentioned, I am using an ABC USB which isolates between the XMOS chip and the oscillators and output section (it has SPDIF out as well, but I am using I2S). As to John's experience I am a little unclear? There is no reason the DAC would be immune to the power supply of the computer, even with (non existant) "perfect" isolation as long as both are connected to the same AC mains. My testing shows, that even with a high quality linear supply for the server/computer, the computer puts way, way more crap out onto the mains than any audio component of my experience (I used to work for PS Audio, and have some experience testing the mains quality, and in reducing AC line noise). My solution is to run as low power a server as possible, Linux/Atom, and to power it completely by LiFePO4-this will result in no mains pollution from the server. So the USB interface isolation stops server noise coming over on USB, and the battery supplied server stops server noise from getting on the mains. Belt and suspenders.

 

[amirm]

Really, Amir, your open-mindedness is showing, I'm afraid.

Have you tried putting marbles in a bowl in your room to see if it improves the sound? Have you replaced all of your volume controls with wooden knobs?

If you are not willing to or not interested in trying this for yourself, why are you bothered posting on this thread - just for arguments?

I have interest in discussing what is being put forward as to the merits of this software which is what the the thread is about: the letter and claims within. They did not post any data. No measurements. No controlled testing. Just a set of arguments. So I answer back in kind. We could actually make forward progress if you could put forward technical arguments that hold water.

 

[amirm]

amirm: If a software add on such results in a significant drop in CPU activity, and the inactivity of a lot of normally running processes, and the resultant decrease in power consumption, is it not likely that reduced noise (both airborne RF products and electrical noise both shared on grounds, and injected back into the mains, assuming and AC powered server/computer) will be the result?

The problem is that drop in CPU activity -- if it were there -- is not necessarily good. We think intuitively that it is. But in reality it may not be. Here is an example. The CPU is waking up 1000 times a second doing a bit of work and then going to sleep. Measuring such CPU usage would show close to 0% load. Now imagine if I fill the gaps with lots and lots of activity from the processor. Now the CPU load is 100%. Which is better? 0%? No! At least not necessarily. That 0% load actually had a correlated spikes at 1 Khz. That is a distinct pulse with a frequency in audible band. The 100% load will actually fill spectrum with random noise. Perceptually we are far less sensitive to noise than orderly events like that 1 Khz pulse train.

Now, if the noise is so high that you hear, then sure, it is a problem. But people building high-end systems don't have noise that this software supposedly removes. And if they did, we would easily be able to measure it. Yet no measurements have been shared to show a reduction of noise.

I really do not believe any of these SW programs magically "improve" the data, but with as many anecdotal reports of improvement as there are, perhaps noise reduction is the only factor involved.
If jplay increases CPU activity, then its use is contrary to my experience.

It doesn't increase the CPU load in an appreciable way as to show up in measurements. It does however use short buffers which means that it has to service it more often. So by definition, it is increasing the very system activity that is said o be bad.

 

[Vincent Kars]

It does however use short buffers which means that it has to service it more often.

This is indeed what I think might be a possible explanation for differences in sound quality by using different players.
As a PC outpaces the audio, there all kind of periodic activities.
These are correlated to buffer sizes (disk, media player, sound card)
Filling or emptying a buffer is a small (100%) burst in CPU, probably too small to be seen by the Win performance graph.
Manipulating this buffers sizes might have an impact.
If it does, it should be measurable on the analog out.

BTW: I tried JPlay some time ago. As I spend an evening to get it working right without success, a couple of BSOD’s included, I decided it was the same type of crap ware as XXhighend and deleted it.

 

[Elberoth]

So the USB interface isolation stops server noise coming over on USB.

There is no such a thing as perfect isolation. What we can talk about is a level of isolation a certain solution provides.

 

[Elberoth]

The approach which does work, is as follows: lets consider a system using the XMOS processor for our example, USB cable comes from server, and goes to the USB receive board (inside DAC). The XMOS processor is powered form the USB bus, and grounded to the host server, this is the "dirty" side of the system. Then the I2S output of the XMOS goes through isolation chips (typically GMRs), these isolate everything including ground.

Those solutions are not as common as you sugest. I'm not arguing they exist, just that they are not as widely used.

I'm pretty sure that If we sampled 100 random DACs with USB inputs, maybe 1 out of 100 would use this approach.

 

[Elberoth]

And no, I have not played with it as it is not a priority for me. Nor a curiosity. All the data I needed is actually in front me: neither its developer or its #1 champion can propose a theory as to why it would improve anything, or any data that shows the same. This is solid data in itself. If you had a theory, and you spent your own time as much as you are asking me to spend to show its efficacy, then we could have something to pursue. But we don't.

Back in mid 80's, there were people that said the same about jitter. Those who were arguing the most were ... software engineers.

Correct me if I'm wrong, but aren't you a software engineer as well ?

 

[jkeny]

No, not at all. I was discussing the approach which is technically correct, and as I mentioned, I am using an ABC USB which isolates between the XMOS chip and the oscillators and output section (it has SPDIF out as well, but I am using I2S). As to John's experience I am a little unclear? There is no reason the DAC would be immune to the power supply of the computer, even with (non existant) "perfect" isolation as long as both are connected to the same AC mains. My testing shows, that even with a high quality linear supply for the server/computer, the computer puts way, way more crap out onto the mains than any audio component of my experience (I used to work for PS Audio, and have some experience testing the mains quality, and in reducing AC line noise). My solution is to run as low power a server as possible, Linux/Atom, and to power it completely by LiFePO4-this will result in no mains pollution from the server. So the USB interface isolation stops server noise coming over on USB, and the battery supplied server stops server noise from getting on the mains. Belt and suspenders.

OK, so you don't have the isolation configuration that you mentioned here - does this mean that you can hear the effects of changes in the Linux PC? I presume this is the case or why would you be going for the next solution.

I take your point about the PS & crap being shunted back onto the main by the standard PC PS. But how this audibly manifests is because of ground loops & with isolation as discussed here the ground would be broken at the DAC so where do you reckon the noise is coming from?

BTW, in your scheme you still have a way for crap getting into the DAC - via the amplifier (if mains operated) you still have a ground connection between PC & amplifier which also still has a ground connection to the DAC via it's analogue outs.

 

[jkeny]

.......
BTW: I tried JPlay some time ago. As I spend an evening to get it working right without success, a couple of BSOD’s included, I decided it was the same type of crap ware as XXhighend and deleted it.

I would recommend revisiting Jplay now - it is far more stable & greatly improved, sonically.

 

[Johnny Vinyl]

I would recommend revisiting Jplay now - it is far more stable & greatly improved, sonically.

Honestly John...how much sonic benefit is going to be gained by the average audiophile? I don't see the point of spending $50 on JRiver and then another $127 (approx) on JPlay. Maybe those with gear in the stratosphere can notice a difference....other than that I'm extremely skeptical.

 

[jkeny]

Have you tried putting marbles in a bowl in your room to see if it improves the sound? Have you replaced all of your volume controls with wooden knobs?

Of course, you are so sure of all the interactions possible in using a PC as an audio device that you sneer at the very idea of such software being able to make a sonic difference. This doesn't just apply to Jplay but all other software players, iTunes, Amarra, Windows Media Player, Foobar, JRiver, etc. According to you, there is no sonic difference between these players.

I have interest in discussing what is being put forward as to the merits of this software which is what the the thread is about: the letter and claims within. They did not post any data. No measurements. No controlled testing. Just a set of arguments. So I answer back in kind. We could actually make forward progress if you could put forward technical arguments that hold water.

Well, if you read the Jplay posts you will see that they say that they don't know what has changed in the output stream & haven't measured any change so I guess you are arguing against people's guesses at the underlying mechanism.

 

[jkeny]

Honestly John...how much sonic benefit is going to be gained by the average audiophile? I don't see the point of spending $50 on JRiver and then another $127 (approx) on JPlay. Maybe those with gear in the stratosphere can notice a difference....other than that I'm extremely skeptical.

Sure, but I've seen equipment being discussed on this forum which costs 10s of thousands - my initial reaction is skepticism too but I keep an open mind & if given an opportunity to hear such equipment take it. So I don't understand people arguing about something which they can try in 5 minutes for no cost?

I have heard dCs stacks & liked what I heard. DO I think they were worth the money - no!
I'm skeptical of Bybees too but would I try them if given a chance - yes!

 

[Johnny Vinyl]

Sure, but I've seen equipment being discussed on this forum which costs 10s of thousands - my initial reaction is skepticism too but I keep an open mind & if given an opportunity to hear such equipment take it. So I don't understand people arguing about something which they can try in 5 minutes for no cost?

I have heard dCs stacks & liked what I heard. DO I think they were worth the money - no!
I'm skeptical of Bybees too but would I try them if given a chance - yes!

Those are fair points to be sure! I've tried JRM and like the interface, but I've not heard any difference in quality using MediaMonkey or MusicBee, which is not to say I won't purchase it down the road. If I do, and JPlay offers a free full trial, then I'd surely be interested in giving it a shot. It should be said that my playback is rudimentary compared to most here, so all of this (for me) may be moot.

 

[barrows]

"OK, so you don't have the isolation configuration that you mentioned here - does this mean that you can hear the effects of changes in the Linux PC? I presume this is the case or why would you be going for the next solution."

what? My USB is indeed isolated (and yes Elberoth, I agree, to a point, that all "isolation" is to a degree, with exceptions-batteries) as I have mentioned three times now, between the XMOS processor and the oscillators/DAC, what I am not sure of is if the ABC-USB re-clocks the I2S feed just before output, but it clearly is isolated. What changes in the server? I do hear changes made to the server power supply (I currently run a very low noise SMPS for the MoBo/HD supply, and a separate shunt regulated supply for the SOtM USB output card), hence my in progress move to a battery powered server.

"I take your point about the PS & crap being shunted back onto the main by the standard PC PS. But how this audibly manifests is because of ground loops & with isolation as discussed here the ground would be broken at the DAC so where do you reckon the noise is coming from?"

I think that you may be missing my point here, regardless of the type of power supply used (and I have tried three different approaches so far, including a standard SMPS, a very high end low noise SMPS, and a full linear power supply) the server still puts a lot of noise back on the AC mains. This noise is generated in the server, not the power supply itself. In fact, even when I powered the server via a dedicated AC regenerator, the same noise from the server still made it to the the AC power cable going into the amplifier. I cannot stress enough how much more noise there is from the server in comparison to the noise generated by any audio component I have ever investigated. My solution is to implement a battery powered server, as the only way to possibly eliminate this problem. Not sure what you are saying ie ground loops: one does not have to have a ground loop to have noise on the mains getting into components and degrading SQ.

"BTW, in your scheme you still have a way for crap getting into the DAC - via the amplifier (if mains operated) you still have a ground connection between PC & amplifier which also still has a ground connection to the DAC via it's analogue outs."

My amplifier has no ground connection to AC mains, and neither does my DAC. I have no G differential in my system, this has been measured.

Elberoth: your point about isolation is well taken, and I agree to a point. Isolators such as transformers, optocouplers, and GMRs are all imperfect devices, and there will always be some capacitive coupling between them. But, this does not mean that they do not help the situation. Of course, as I mentioned. When I battery power the sever that will provide fill isolation of the server from the AC mains.

 

[jkeny]

Barrows, by your description of your configuration, you have just proven that there are probably very few systems that offer the isolation you are talking about. Contrary to what you stated/claimed initially "I am a little bewildered by jkenny's apparent lack of knowledge on how to properly isolate a USB interface though? I thought he was much more knowledgable about this?". You then go on to describe an XMOS based system which only partially isolates the DAc & now have described your system & the lengths you have gone to & are still striving for a better solution!!

I'm confused by this shifting of opinion - is it easy to isolate as you claimed initially or at least claimed my statement that it was difficult was erroneous