Airplay Sound Quality-does a wireless transport make any difference if you are not using a dac?

[WinterRacer]

Digital cables have no effect on sound because they don't deal with sound, they have nothing to do with sound. Each and every one of them enables data transfer.

Why would anyone think they can effect sound quality?

Perhaps some of the 'hi-end' cables have mini battery-powered DSP chips built into them that process the raw S/PDIF data and apply "increase soundstage", "bass lift" and "grain removal" algorithms to the data?

Actually, for the cost, that's not an unreasonable request, is it?

 

[Anonymous]

Digital cables have no effect on sound because they don't deal with sound, they have nothing to do with sound. Each and every one of them enables data transfer.

Why would anyone think they can effect sound quality?

Perhaps some of the 'hi-end' cables have mini battery-powered DSP chips built into them that process the raw S/PDIF data and apply "increase soundstage", "bass lift" and "grain removal" algorithms to the data?

Actually, for the cost, that's not an unreasonable request, is it?

 

[John Duncan]

I'm not sure of the purpose of your post, do you really want to know more about how network protocols work, or something else? Anyway, I’d still argue that random errors in data words do not result in more bass or treble. Warbling perhaps

My purpose was to point out that I've experienced something other than clicks or pops. And if a warbling were a bit less obvious than my warbling and was happening at, say, 50hz or 7khz, surely it *could* produce more (or at least different) treble or bass. In summary, I'm saying that a less than perfect wireless transfer could feasibly alter the sound in subtle ways, without manifesting itself as obvious artefacts.

 

[WinterRacer]

I'm not sure of the purpose of your post, do you really want to know more about how network protocols work, or something else? Anyway, I’d still argue that random errors in data words do not result in more bass or treble. Warbling perhaps

My purpose was to point out that I've experienced something other than clicks or pops. And if a warbling were a bit less obvious than my warbling and was happening at, say, 50hz or 7khz, surely it *could* produce more (or at least different) treble or bass. In summary, I'm saying that a less than perfect wireless transfer could feasibly alter the sound in subtle ways, without manifesting itself as obvious artefacts.

How would lost packets of data be restricted to specific frequencies? Remember, whilst the data is binary and in packets, frequencies, as you've described them, don't really exist.

My DAB radio in my car warbles if I lose my signal, but I never get more or less bass (in relation to other frequencies that is).

Do you have problems with wifi coverage in your house with other devices?

 

[WinterRacer]

I'm not sure of the purpose of your post, do you really want to know more about how network protocols work, or something else? Anyway, I’d still argue that random errors in data words do not result in more bass or treble. Warbling perhaps

My purpose was to point out that I've experienced something other than clicks or pops. And if a warbling were a bit less obvious than my warbling and was happening at, say, 50hz or 7khz, surely it *could* produce more (or at least different) treble or bass. In summary, I'm saying that a less than perfect wireless transfer could feasibly alter the sound in subtle ways, without manifesting itself as obvious artefacts.

Re: lost packets manifesting in subtle ways. With a squeezebox, Linn streamer and others using TCP, all that will occur is buffer starvation. With streaming protocols over UDP, it's up to the implementation what they do if they can't correct the data. It's normal to mute the output, but other approaches could be used, including retransmission of corrupt packets controlled at the application layer.

In practice, if it's a problem, move your router, get a repeater or use Ethernet (over power).

 

[Andrew Everard]

or use Ethernet (over power)

 

[John Duncan]

How would lost packets of data be restricted to specific frequencies?

I'm not saying that they would, I'm saying that artifacts from poor digital transmission could manifest themselves as such at particular frequencies. As opposed to the signal just being on or off. I'm being hypothetical because I really don't know, but am wondering whether it's analogous to vinyl having a 50Hz motor drone going on.

Do you have problems with wifi coverage in your house with other devices?

Not really, no.

 

[WinterRacer]

How would lost packets of data be restricted to specific frequencies?

I'm not saying that they would, I'm saying that artifacts from poor digital transmission could manifest themselves as such at particular frequencies. As opposed to the signal just being on or off. I'm being hypothetical because I really don't know, but am wondering whether it's analogous to vinyl having a 50Hz motor drone going on.

I honestly can't imagine how they would. I would say that artefacts such as that would have to occur after the D to A conversion and nothing to do with packets lost over wifi, toslink, etc.

 

[Anonymous]

You can't turn it off, that's what the Apple TV does. I'd be amazed if it's causing any problems though. I use an Apple TV 3 and have no problems with sound quality with it.

Just to rule it out, have you tried a blind test to make sure the differences are real? It's easy to imagine differences, especially when we have the idea that absolutely everything affects sound quality pushed by various communities.

I know what you mean about the placebo effect. However, it was a shock to me how the sound signature of my entire system changed through the ATV, hard to fathom why, I haven't experienced the same change via airport express and airplay. I think that it might be the optical cable I use to connect my ATV, as its different from the one I use for my mac. I don't believe in digital cables making a difference boohah, but I think I'll give it a try and see if it changes things.

Hi Shafin, the thing is, that using a different digital cable simply cannot improve the resultant sound, the quality or build of a digital cable has nothing to do with sound in as much as, it'll either work, and the data will arrive at the DAC, or it won't, and the data won't arrive at the DAC.

This is quite a simple thing to understand, and it means that either you imagined your system sounded better after changing the digital cable, or something outside of the digital domain was changed, and this was responsible for the perceived change in sound quality.

 

[Andrew Everard]

Hi Shafin, the thing is, that using a different digital cable simply cannot improve the resultant sound, the quality or build of a digital cable has nothing to do with sound in as much as, it'll either work, and the data will arrive at the DAC, or it won't, and the data won't arrive at the DAC.

Because...? Show your working, write on only one side of the paper, etc...

This is quite a simple thing to understand, and it means that either you imagined your system sounded better after changing the digital cable, or something outside of the digital domain was changed, and this was responsible for the perceived change in sound quality.

Trenchant though you may be in your beliefs, probably not a good plan to suggest other forum members are deluding themselves.

 

[Anonymous]

Hi Shafin, the thing is, that using a different digital cable simply cannot improve the resultant sound, the quality or build of a digital cable has nothing to do with sound in as much as, it'll either work, and the data will arrive at the DAC, or it won't, and the data won't arrive at the DAC.

Because...? Show your working, write on only one side of the paper, etc...

This is quite a simple thing to understand, and it means that either you imagined your system sounded better after changing the digital cable, or something outside of the digital domain was changed, and this was responsible for the perceived change in sound quality.

Trenchant though you may be in your beliefs, probably not a good plan to suggest other forum members are deluding themselves.

Hi Andrew

Shafin said that when streaming to the ATV, he felt he was only getting 90% of the sound quality as opposed to when the data was being transferred through a digital cable.

This is not possible, and that doesn't mean that Shafin is deluded , it's very easy to get caught up with advertising spin etc, and hear what you may or may not expect to hear in a these types of comparisons.

Digital data doesn't do 90%, or 80%, it does 100%, and thus the 10% difference Shafin mentioned was in fact either imagined or due to something outside of the digital domain.

 

[Andrew Everard]

Shafin said that when streaming to the ATV, he felt he was only getting 90% of the sound quality as opposed to when the data was being transferred through a digital cable.

This is not possible, and that doesn't mean that Shafin is deluded , it's very easy to get caught up with advertising spin etc, and hear what you may or may not expect to hear in a these types of comparisons.

Digital data doesn't do 90%, or 80%, it does 100%, and thus the 10% difference Shafin mentioned was in fact either imagined or due to something outside of the digital domain.

No, he said that

I'm trying out different cables atm to see what can bring it 90% of a wired connection to my mac. Wish me luck

In other words, he feels the Apple TV is underperforming in sonic terms when connected to his DAC, compared to the sound of his computer connected directly to the same DAC.

I agree with you that changing cables isn't going to improve this, simply because IMHO the Apple TV, not least due to its totally superfluous resampling of 44.1kHz audio to 48kHz, sounds pretty rubbish, and Airplay streaming compounds the problem by adding its own problems.

Convenient, maybe, and good for impressing your friends at least once – 'look, look, I press this button on my iPhone, and music comes from the speakers' – but unless you're happy to play nothing better than heavily data-reduced music from rips or Spotify (ugh!), not the solution for high quality.

So, given that he has (again IMHO) a somewhat rubbish sound already via that particular route, no cable is ever going to improve it. His best bet is to stick to a direct connection from computer to DAC, or look at alternative streaming technologies, rather than falling for the 'advertising spin etc' of this particular branch of the Apple plan for world domination.

A victory for Flinnian logic? Hardly – after all, cables can only lose or restrict the information fed into them, in whatever format; they can't magically add data that's already lost elsewhere upstream of them.

In other words, the best cable is the least bad cable.

 

[shafesk]

A few days off this forum and the thread has turned confusing. Well I haven't bought any new cable, just used an existing one. What I've found is rather interesting. Airplay via apple tv to dac magic through a different optical cable sounds better than a 10 foot usb cable via macbook to dacmagic. Then again I should mention that the optical cable I used before has been rendered completely useless, maybe thats why I was noticing huge sonic differences between my macbook and dacmagic. Unfortunately, I cannot test whether a direct connection from my macbook to the dacmagic via optical sounds better than optical to dac magic and atv since the optical cable is way too short. As far as I remember it sounds the same, then again I do not have the most revealing dac so the differences Andrew mentioned here might be better revealed in a better setup.

I want to point something out to Andrew here, I think he is better equipped to make sense of this than me. Before, when I was using the nearly dead optical cable and atv I noticed a totally different sonic signature that was immediately noticeable, it was the kind of difference that you could tell without paying much attention. That lead me to change the optical cable, now it sounds like my system (although there might be soundstaging, lesser details which I haven't compared enough). Do you think that a digital cable can make things so bad? Or is it the Atv was "Burning in" and now has settled down? I'm really baffled here.

I'll try and see if I could get someone to conduct a blind test for me when I get a longer optical cable to see if I can tell the difference between the mac and the atv via optical. It makes sense that if the atv is upsampling 44 khz to 48 and then is fed into an upsampling dac that it sounds totally rubbish.

 

[jcbrum]

In other words, the best cable is the least bad cable.

That qualification may have some bearing in the analogue domain, but in the digital domain, it is not accurate.

In digital terms, the perfect cable is one that is merely good enough. No further improvement will have any effect.

'Good enough' means all the bits in the right place, with an acceptable error in time. All digital signals jitter, which is tolerable, and inconsequential.

The important thing is that the received file be exactly the same digital string as was transmitted. There is no 'music' to be affected, merely a string of data.

Given the above qualifications, and effective error checking, buffering, and re-clocking (which is nothing to do with the cable), it doesn't matter a jot whether you transmit files via radio, satellite, wires, or light beams.

Any audible differences will be due to the analogue converter (nothing to do with the cable employed) or imagination.

It would be tedious to further discuss Malcolm Steward's faux-pas in this respect, but it is relevant.

JC

 

[Anonymous]

Hi Shafin

Just letting you know I've now plugged my ATV directly into my Denon AVR-1906 with the optical cable and there is a massive difference!

Cheers,

Karl

 

[Andrew Everard]

That qualification may have some bearing in the analogue domain, but in the digital domain, it is not accurate.

In digital terms, the perfect cable is one that is merely good enough. No further improvement will have any effect.

'Good enough' means all the bits in the right place, with an acceptable error in time. All digital signals jitter, which is tolerable, and inconsequential.

The important thing is that the received file be exactly the same digital string as was transmitted. There is no 'music' to be affected, merely a string of data.

Given the above qualifications, and effective error checking, buffering, and re-clocking (which is nothing to do with the cable), it doesn't matter a jot whether you transmit files via radio, satellite, wires, or light beams.

Any audible differences will be due to the analogue converter (nothing to do with the cable employed) or imagination.

It would be tedious to further discuss Malcolm Steward's faux-pas in this respect, but it is relevant.

JC

I wasn't aware we were discussing Malcolm, nor indeed am I aware of him making a faux-pas.

Anyway, I agree that it's important 'that the received file be exactly the same digital string as was transmitted', but disagree that, simply because the digital signal can be reconstituted by 'error checking, buffering, and re-clocking', it's acceptable to use any old cable through which the signal can just about make it in some recoverable form – surely it's better to get the signal through in as intact a form as possible, so that all that post-processing doesn't have to be done before it can be converted into analogue?

I guess it comes down to whether one is prepared to settle for 'merely good enough', or endeavours to achieve the best one can. I mean, I listen to podcast radio programmes in the car when I am commuting, most of which are at very low data-rates, and they sound fine. But play them on a decent home system, and their limitations are all too apparent – a case of 'merely good enough' not really being good enough.

I guess it depends on the quality of the equipment on which you're listening, and its ability to let you hear the differences between 'good enough' and excellent.

And how on earth can any audible differences be due to the analogue converter – I assume you mean digital-to-analogue converter – when I'm sure I read somewhere the opinion that all DACs, provided they're implemented properly, sound the same?

I suspect we're not going to agree on this one.

 

[shafesk]

Interestingly (mods delete it if I am breaking rules here) http://www.stereophile.com/digitalprocessors/505apple/ shows that the airport express makes a "respectable digital transport for very high end systems"

 

[Andrew Everard]

Interestingly (mods delete it if I am breaking rules here) http://www.stereophile.com/digitalprocessors/505apple/ shows that the airport express makes a "respectable digital transport for very high end systems"

Or at least did by the standards of seven years ago.

 

[Anonymous]

Interestingly (mods delete it if I am breaking rules here) http://www.stereophile.com/digitalprocessors/505apple/ shows that the airport express makes a "respectable digital transport for very high end systems"

Or at least did by the standards of seven years ago.

I don't think anything's changed in that time Andrew, digits are still digits are they not? If they get to the DAC then whatever got them there has done it's job and nothing else could have done it any better, would you agree?

 

[Andrew Everard]

If they get to the DAC then whatever got them there has done it's job and nothing else could have done it any better, would you agree?

No, but if you are satisfied with the performance offered by these rather restrictive devices, then enjoy your music and be happy.

 

[Anonymous]

If they get to the DAC then whatever got them there has done it's job and nothing else could have done it any better, would you agree?

No.

, Andrew, you said yourself that a digital cable cannot improve anything, so how can a streamer do so?

 

[Andrew Everard]

Andrew, you said yourself that a digital cable cannot improve anything, so how can a streamer do so?

I said that a cable cannot improve things, but can minimise losses so that the receiving device has less work to do. The same applies to a well-implemented streamer, able to process the incoming data to a higher standard and thus present a 'cleaner' digital data-stream to the digital-to-analogue conversion.

 

[Anonymous]

Andrew, you said yourself that a digital cable cannot improve anything, so how can a streamer do so?

I said that a cable cannot improve things, but can minimise losses so that the receiving device has less work to do. The same applies to a well-implemented streamer, able to process the incoming data to a higher standard and thus present a 'cleaner' digital data-stream to the digital-to-analogue conversion.

There's no such thing as a cleaner digital data stream

It's either corrupted to such a degree that it cannot be fully reconstituted - and you won't hear the music, or, it can be fully reconstituted - and you will hear the music,

Nothing, no cable or streamer, can improve a digital data stream, either 100% of it is converted by the DAC, or there is a failure as the DAC (or codec in the case of HDMI) does not have all the data to process

 

[Andrew Everard]

There's no such thing as a cleaner digital data stream

It's either corrupted to such a degree that it cannot be fully reconstituted - and you won't hear the music, or, it can be fully reconstituted - and you will hear the music,

Nothing, no cable or streamer, can improve a digital data stream, either 100% of it is converted by the DAC, or there is a failure as the DAC (or codec in the case of HDMI) does not have all the data to process

I said 'able to process the incoming data to a higher standard and thus present a 'cleaner' digital data-stream to the digital-to-analogue conversion' – in other words, do a better job of reconstituting (to use your word) the incoming data, reducing or (ideally) removing the effects of jitter, transmission losses and the like.

I'm not talking about 'improving a digital data stream': I'm talking about doing a better job of putting right the damage done further upstream in the chain between the source of the data and the DAC.

Anyone believing in 'perfect or not there at all' has never heard the differences between CD players, seen 'sparklies' on a TV screen or heard 'bubbling mud' on a DAB transmission.

 

[jcbrum]

I wasn't aware we were discussing Malcolm, nor indeed am I aware of him making a faux-pas.

You must be one of the few 'computer-audio' enthusiasts in the world who isn't aware of his almost universally derided remarks concerning changing his hard-drive data cable to improve his audio quality.

It's a classic example of digital cable foo, which has already been discussed ad-nauseum, hence my remark that whilst it was relevant, there's no mileage in discussing it further.

I guess it comes down to whether one is prepared to settle for 'merely good enough', or endeavours to achieve the best one can. I mean, I listen to podcast radio programmes in the car when I am commuting, most of which are at very low data-rates, and they sound fine. But play them on a decent home system, and their limitations are all too apparent – a case of 'merely good enough' not really being good enough.

I think that has more to do with the compression technology, and the low data rate, employed, rather than the fact that digital propagation is employed. If what you said was generally true of digital transmissions, the internet, and world-wide data systems, and music downloads of any type, wouldn't work properly.

And how on earth can any audible differences be due to the analogue converter – I assume you mean digital-to-analogue converter – when I'm sure I read somewhere the opinion that all DACs, provided they're implemented properly, sound the same?

The analogue converter, which is that part of a complete 'DAC' (in a hifi equipment sense), is the only part you can 'hear'. It's what produces the 'analogue', - you can't 'hear' digits, and perceive music.

I suspect we're not going to agree on this one.

Possibly, but put your faith in 'a ray of light' emerging

JC