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Sound quality of shared iTunes library wireless

Hi Everyone,

I hope this isn’t a dumb question, but here it is. First a little background.

In my two channel system I have an old iMac serving up my music files via a Schitt Bifrost DAC. I uploaded all my CDs to iTunes in a lossless format (AIFF) and they are stored on a 7200 RPM external firewire drive. The old iMac has a small hard drive and can’t handle my music collection. I have been super happy with this and it was a big step in sound quality over my old Rotel CD player.

I also have a spare MacBook Pro with a bigger drive. Recently I copied the entire music library to it’s drive and have this upstairs. To be clear, the Macbook has the same exact iTunes library with the same lossless files.

Today I was playing around and accessed the MacBook’s music library from the iMac via my home wireless network and iTunes sharing. I compared a number of the same tracks - from the connected hard drive and from the shared library wireless. It *seems* to sound exactly the same, but I find myself second guessing and imagining things. So, that is my question. Does it sound the same? Should it? Since they are the same exact files, it seems the only limiting factor is the speed of my wireless network, right? There is no compression or any other funny business via sharing… or is there?

I realize that if I can’t tell, what does it matter, but some of you guys know everything about this and I am curious. Plus, I have other uses for that 2 TB drive and would like nothing more than to use the iMac to access my music wirelessly like this.

Thanks in advance
karavite
8 responses Add your response
mceljo
1,357 posts
 
I recently picked up a DAC and am now using iTunes on my PC via an Apple TV as a source. I have been unable to tell a difference between the DAC and my CD player. Even knowing the Apple TV has issues from an audiophile perspective I can't hear a difference.

I think you are on to something.
karavite OP
36 posts
 
Thanks Mceljo. I spent the better part of yesterday ABing the same tracks and I could not tell either, but then I wonder if I lack the sommelier-esque listening palate of so many audiophiles - not to mention an endless supply of clever adjectives, metaphors and similes. :-)

However, I still want to know the technical answer. In non technical terms, in my set up, both options are accessing the same source file - right? The music is NOT being transmitted, it is the data.
mceljo
1,357 posts
 
It all boils down to your view of the digital side of audio and your physical ability to hear the differences. In theory, if the data is transmitted to the DAC bitperfect then the results should be identical.

In the case of my Apple TV, the data gets converted to 48kHz which is the TV standard so I know that in theory it is inferior compared to even an Airport Express that converts to 44.1 kHz, but I still cannot hear a difference in my system. I am sure that it may be possible to hear the difference in some systems.
richardfinegold
196 posts
 
I didn't quite follow that list part. Why would Apple TV at 48 kHZ be inferior to Airport Express at what seems to be a slightly lower rate?
kijanki's avatar
kijanki
4,428 posts
 
Why would Apple TV at 48 kHZ be inferior to Airport Express at what seems to be a slightly lower rate?

Because there is some loss of quality on 44.1kHz to 48kHz conversion.

Karavite, If data is identical then the only thing that change sound is timing. If you send music in form of S/Pdif stream from computer to DAC any time variation (time jitter) converts to noise. In case of wireless you send data without timing, most likely in packets. This data is saved in the receiver buffer (in my AE couple of seconds) and new timing is created either for internal D/A converter (if you use analog outs) or external DAC (if you use digital out). Since your computer timing is unimportant you can use slow computer, any HD drive etc. The only way computer can affect the sound, in this configuration, is thru the ambient electrical or mechanical noise in the room. In that respect faster computer can be much worse (more electrical noise, stronger fans).
karavite OP
36 posts
 
Thanks Kijanki, I think I understand. I hear no difference at all. Please realize I am not using Airport or Apple TV. I have one Mac with my lossless files and it is sharing the files (not streaming) to other computers via iTunes sharing.
mceljo
1,357 posts
 
To clarify, the digital files are being fed from the same computer to the DAC? If so, you should expect identical playback unless there is a wireless glitch in the sharing process in which case you may hear the music drop for a split second.

What is the gateway to the DAC?
mwp7373
29 posts
 
I also use an apple TV (2nd Gen) to wirelessly deliver my music collection (iTunes-ripped AIFF files on a windows 7 computer) from one room to another. I purchased one of the Remedy Reclocker units from Wyred4Sound which now sits between the ATV and the DAC and I believe this arrangement does a very good job with redbook files. The W4S site has an interesting graphic about the jitter reduction achieved. (I'm not associated with W4S in any way other than a consumer of their products). The real drawback is that this approach dead ends everything as far as hi-rez streaming goes so far as I can tell from what I've read. Any insights on how to get around that one would be welcome.
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