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

[shafesk]

Hello again, fellow forum members.

Having recently purchased an Apple Tv, which is connected through my dacmagic and to my speakers I found the sound quality a bit worse than when my macbook is connected to my dacmagic via optical using the same cables. The sound is a bit bright and I'm missing some tight bottom end. Anyone else have this issue? Can you also tell me that if I were to better the Apple Tv using a streamer, is it possible provided that I use the dacmagic? It is my opinion that more expensive streamers sound better simply because they use more expensive dacs. If you remove the dac from the equation I reckon a wireless streamer as a transport doesn't make that much of a difference. Thoughts and arguments absolutely welcome.

Cheers,

Shafin

 

[ifor]

In my experience wireless falls short of wired. I use Airport Express where you use Apple TV and Arcam rDAC where you use the DACmagic. When iMac and Airport Express are working wirelessly sound quality is poor. So I have turned off WiFi on iMac and Airport Express and connected them via Ethernet and Devolo HomePlugs. The result is excellent.

 

[WinterRacer]

It's not music being transmitted over the (wireless) network, it's packets of data transmistted using well known network protocols. If so many packets are lost such the original data cannot be reconstructed, you'll get a silence or click, not more treble or a less tight bass.

One obvious things to check is to make sure you haven't got any EQ set when using the mac. Failing that, the apple tv does resample everything to 48KHz. This is generally considered to be inaudible, but you never know.

 

[ifor]

Points well made by WinterRacer. I should have made it clear that my sound quality issue when wireless were dropouts rather than sound quality issues.

When I first started streaming from the iMac I had it set to adjust volume so that it was equal regardless of the recording volume. Bad mistake!! Presumably this would affect wired as well as wireless.

 

[shafesk]

Thank you for your suggestion, I am not (thankfully) being affected by dropouts so I think I can avoid the hassle of having a wired connection. I don't know how to turn off Apple Tv resampling everything to

48khz, according to the dacmagic's display it is playing at 48khz now.....any idea how to do this? All I can see is the 16 bit option on the Apple Tv

 

[WinterRacer]

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.

 

[shafesk]

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.

 

[busb]

I've just had to return to using my ATVII. I bought the newest model whose only difference is supposed to be 1080p HD video instead of 720p. I'm hoping that the new one is faulty 'cos I'm getting serious dropouts on audio over WiFi & will be returning it to the Apple shop I bought it from soon.

That aside, my ATV works very well - I usually use it via a PC connected to my router via Ethernet that then gets streamed to my ATV over WiFi. The ATV is connected to my M-DAC through a cheap 0.5m optical lead. Although I haven't done a recent comparison, the difference of streaming Apple lossless, 256k & 320k files versus my Rotel CDP (1m coax) was good enough for me not to worry. A good friend who's ears I trust felt the same - streaming over WiFi sounded no worse. He is 60 & I'm fast approaching the same so our ears are probably poorer than they used to be. I mention this because I recently tried the ABX MP3 comparison test here:

http://mp3ornot.com/

and failed badly! I'm not a huge fan of such short tests of music I'm not familar with anyhow but many see such tests as conclusive - I'm less convinced. iTunes sounds marginally better from my laptop through synchronous USB but close enough to be my imagination (as long as it runs on battery power!). I also use iTunes Match that streams at no higher than 256k when my PC is switched off in my bedroom - can't say I noticed any difference but neither am I particularly searching for one - I prefer to just enjoy music & fix any problems when I notice them.

 

[shafesk]

Thank you for your opinion busb, I would not have been worried if it was a tiny difference as I really like the convenience of the Apple Tv. However, the difference is striking and as streaming music is my main source I think its far too important not to get wrong. I'm trying out different cables atm to see what can bring it 90% of a wired connection to my mac. Wish me luck

 

[busb]

Thank you for your opinion busb, I would not have been worried if it was a tiny difference as I really like the convenience of the Apple Tv. However, the difference is striking and as streaming music is my main source I think its far too important not to get wrong. I'm trying out different cables atm to see what can bring it 90% of a wired connection to my mac. Wish me luck

I do indeed wish you luck 🙂

As you don't know me you can conclude that either I've got cloth ears or that the ATV works fine for some people so it's just a matter of sorting out why it isn't for you. No surprises that I go with the latter!

 

[Anonymous]

Hi Shafin

Hope you got to the bottom of the ATV sound quality issues. I've been using my ATV2 for over a year now and I’m really happy with the sound quality. I can't tell the difference between the ATV wirelessly streamed music and a cable straight from my mac into the amp.

I mainly use Spotify premium streaming 320kbps into the ATV plugged directly into a Denon AVR-1906 (no separate DAC) with B&W 684 speakers.

 

[the record spot]

Currently using Spotify Premium over wireless into the ATV3. I can't fault the sound quality, it's as good as the wired version and as good as the CD player.

 

[shafesk]

Hi Shafin

Hope you got to the bottom of the ATV sound quality issues. I've been using my ATV2 for over a year now and I’m really happy with the sound quality. I can't tell the difference between the ATV wirelessly streamed music and a cable straight from my mac into the amp.

I mainly use Spotify premium streaming 320kbps into the ATV plugged directly into a Denon AVR-1906 (no separate DAC) with B&W 684 speakers.

Hey Karl, if you have the Denon then you can use a spdif cable to connect the ATV to your Denon, it will then use your Denon's dac and will considerably improve sound quality.

 

[shafesk]

Thank you Karl and TRS for sharing your opinions. I have managed to sort out the problem, I was using a really cheapo spdif cable, I switched to a better built one and the lack of solidity disappeared. I don't think I can tell the difference between the ATV and a direct spdif connection to my mac anymore since last night. I'm not gonna open a can of worms and say digital cables make a difference but I rest my case.

Best Regards,

Shafin

 

[Anonymous]

Hi Shafin

What's the difference between a spdif and "normal" optical cable and why would using a spdfi bypass the ATV DAC and use the Denon one? Or am I missing the point entirely?

I'm pretty new to all this so please forgive my ignorance!

Thanks,

Karl

 

[Paul.]

Spdif is the stubby square head optical connection, whereas the normal connector has the same shape as a 3.5mn jack. You can get adapters between the two.

 

[Anonymous]

Thanks Paul. I think I might be using a spdif cable then...would you mind posting a link to each type so I can be certain?

 

[shafesk]

Hey Karl, well a spdif cable carries the digital signal bypassing the internal dac. SPDIF and optical cables are the same if I recall correctly, whereas a toslink cable is shaped like a 3.5mm headphone jack. Here's a link http://www.amazon.co.uk/Fisual-Install-Series-Digital-Optical/dp/B000WTM2PU/ref=sr_1_4?ie=UTF8&qid=1341478014&sr=8-4 Even if I'm getting the differences mixed up, this is basically the cable you need to run from your ATV to your Denon receiver to bypass the ATV dac.

 

[Anonymous]

Thanks Shafin. I've ordered it already and looking forward to it 🙂

 

[shafesk]

good to know buddy, please let us know your findings and don't let me or anyone else make you believe that it'll change things till you get to hear it.

 

[Overdose]

S/PDIF is a digital data transfer protocol.

The connection types are typically TOSLink (optical), or 75 ohm co-axial wired connection.

TOSLink is the squareish shaped optical connector.

 

[John Duncan]

It's not music being transmitted over the (wireless) network, it's packets of data transmistted using well known network protocols. If so many packets are lost such the original data cannot be reconstructed, you'll get a silence or click, not more treble or a less tight bass.

And yet, on using Airfoil Speakers to 'airplay' from my iPhone to my iMac, there's an inconsistency in sound quality (warbling and wavering) which is not the simple on/off that some would argue is the only thing that can happen with a wireless network. Explain...

 

[WinterRacer]

It's not music being transmitted over the (wireless) network, it's packets of data transmistted using well known network protocols. If so many packets are lost such the original data cannot be reconstructed, you'll get a silence or click, not more treble or a less tight bass.

And yet, on using Airfoil Speakers to 'airplay' from my iPhone to my iMac, there's an inconsistency in sound quality (warbling and wavering) which is not the simple on/off that some would argue is the only thing that can happen with a wireless network. Explain...

Airplay is based on UDP, UDP has error detection and correction built in, but unlike TCP, does not have packet retransmission built in. If packets are lost, the receiver can work out what the data should be, known as interpolation. If enough packets are lost, it'll just give up and you'll get silence, but this could be the effect you're hearing. Alternatively, you might just have a dodgy device somewhere...

Typically, Apple are not very forthcoming about how their protocol works exactly, someone claimed Apple had built retransmission at the application layer (of the network stack), but I haven't seen that info for myself.

If it's something that worries you, use a streaming protocol that runs over TCP, e.g., Squeezebox and Linn. TCP is known as a reliable network protocol. If packets are lost, all that happens is network bandwidth is reduced and the receiving buffer will be starved. If you've ever seen a Squeezebox rebuffering, you'll have seen and heard the effect of this - silence.

Hope that helps?

 

[WinterRacer]

If you think about UDP based streaming protocols as similar to a how a CD player works. The data on a CD player allow for simple error detection and correction. If enough data read errors occur, the protocol can’t correct the data and you’ll hear a click/pop or in extremis, silence.That’s pretty similar to what you’re hearing.Perhaps you’re just trying to prove something, but I’d still argue that random errors in data words do not result in more bass or treble. Warbling perhaps 🙂

If you think about UDP based streaming protocols as similar to a how a CD player works.

The data on a CD player allow for simple error detection and correction. If enough data read errors occur, the protocol can't correct the data and you'll hear a click/pop or in extremis, silence. No doubt you've heard this? That’s pretty similar to what you’re getting with Airplay (a UDP based network protocol).

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 🙂

 

[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?