[El Bishop]

Trying to get the clutter off my desk. Currently, my terabyte external HD is connected via USB to my MBP. I have a netgear g router and an Airport Express, which I use to stream music to my stereo. If I replace the Netgear router with an Airport Extreme, can I connect my external HD directly to its USB port and then expect to stream bit for bit from that HD to my MBP and then to the Airport Express or will I lose something along the way?

Also, is the only difference between the Airport Express and the Time capsule the HD in the latter?

Thanks very much!

 

[krmathis]

I expect that to work fine.
The disk connected to the AirPort Extreme should show up on your computer, and from which you play music. WLAN is more that capable of streaming from the AirPort Extreme to the AirPort Express at the same time, speed wise.

The difference between the AirPort Express and the Time Capsule is more than just the HD. The later one I suspect have a stronger signal strength and also a more configurable network. AirPort Extreme and Time Capsule on the other hand is much closer in function.

 

[El Bishop]

Sorry - meant what is the difference between Airport Extreme and Time Capsule -- guessing they are pretty similar other than the HD

 

[darwinshardhat]

Have you been using the Airport Express and are you happy with the sound quality doing it that way?

From a performance perspective receiving audio wirelessly on an Airport Express is the only step in the chain that is going to lose bit for bit quality. Your other computer hardware will have the ability to get every bit from point to point with error correction. I'm not sure what it is about the Airport Express but that's what I've heard from an Apple Engineer a coworker knows. It may be the method of converting the data signal to digital audio in the Airport Express that is cheaply implemented. That coworker uses a mac mini at his stereo location and goes out to a firewire DAC from there. Even better I think would be to go from the Mac Mini to a high quality USB ->SPDIF converter and go into your DAC from there, but that's a much bigger investment.

 

[El Bishop]

Thanks. Airport is actually pretty good and it's what I'll be using until someone tells me there's a better product. It does have an SPDIF/optical output and as far as I've been able to ascertain does receive a bit for bit accurate transmission from the computer.

 

[krmathis]

Quote:

Originally Posted by darwinshardhat /img/forum/go_quote.gif From a performance perspective receiving audio wirelessly on an Airport Express is the only step in the chain that is going to lose bit for bit quality. Your other computer hardware will have the ability to get every bit from point to point with error correction.

Its been verified that the AirPort Express' digital out (optical) is bit-perfect.
So its a quite safe choice, I would say.

 

[xenithon]

Bear in mind though, IIRC, the Airport Express's digital optical output is limited to 16/44.1; whereas the optical out of a Mac machine (Macbook, Mac Mini, iMac) can go up to 24/96. Particularly important if you are playing hi-rez files.

 

[audioengr]

Putting an AE to feed an Esoteric DAC is like putting a $10 cartridge on a $10K turntable IMO. The AE is one of the worst WiFi devices for jitter. In fact, of all the WiFi devices, the Duet/Squeezebox has the lowest jitter, and even this needs reclocking.

Steve N.
Empirical Audio

 

[El Bishop]

I know the AE is the weak link in the chain but the convenience of the iPod remote when not using the CD transport . . .

What would you recommend as a good long term solution for my hard drive based collection? A dedicated music server connected directly to teh DAC? Does that take care of jitter? I assume that the digital files can be transfererd wirelessly. It seems as though all teh wireless solutions are far from perfect for teh time-being.

 

[grawk]

Quote:

Originally Posted by audioengr /img/forum/go_quote.gif Putting an AE to feed an Esoteric DAC is like putting a $10 cartridge on a $10K turntable IMO. The AE is one of the worst WiFi devices for jitter. In fact, of all the WiFi devices, the Duet/Squeezebox has the lowest jitter, and even this needs reclocking. Steve N. Empirical Audio

I didn't think members of the trade were allowed to comment negatively on their competition?

I've never been able to hear the effects of jitter, and the airport express to a dac works very well. Is it the best possible transport? Probably not, but it sounds good and is darn convenient.

 

[nick_charles]

Quote:

Originally Posted by grawk /img/forum/go_quote.gif I've never been able to hear the effects of jitter.

Nor are you ever likely to. In the 10 years since Benjamin and Gannon (Dolby Labs) assessed audible jitter levels nobody has provided substantive empirical evidence to suggest that they were off the mark and they measured jitter audibility in the 10 - 30 ns range in a worst case scenario using signal correlated jitter on a high frequency tone and then embedded in music.

In fact only one audio device commercially available has jitter in excess of 10ns and that is so measurably bad in so many other ways that jitter is the least of its problems and even Stereophile did not like it much, nor was it cheap...

 

[audioengr]

I dont like dedicated music servers because they have limited lifetime and trap you into certain players and formats, usually not optimum. Separates are better IMO.

Actually Sonos is pretty perfect, and a lot of folks like the Duet and Squeezebox too. I have SB3, but I dont care too much for Squeezecenter. I like the Sonos better. Go to Sonos.com and run the demo. Really well-designed IMO. You can control it from iPhone or iPod touch too.

The only issue with all of these is jitter.

And dont get me started on jitter. It is real and those of you that dont believe you hear it are likely hearing it, or the other noise in your systems is so large that it is masking it. Once it is gone, the difference is obvious in most systems. The majority of industry experts in computer audio agree that jitter is the #1 concern. Here is their feedback:
ca intro

And furthermore, the AE is not a product competitive with mine. I dont sell any WiFi devices.

Steve N.
Empirical Audio

 

[El Bishop]

Thanks, Steve.

So does the sonus produce superior sound quality (i.e., better than 16/44.1)? or is it just the functionality?

 

[nick_charles]

Quote:

Originally Posted by audioengr /img/forum/go_quote.gif I And dont get me started on jitter. It is real and those of you that dont believe you hear it are likely hearing it, or the other noise in your systems is so large that it is masking it. Once it is gone, the difference is obvious in most systems. The majority of industry experts in computer audio agree that jitter is the #1 concern. Here is their feedback: ca intro

If you look at the actual measurements for digital audio devices a clear pattern emerges. Both IMD and Harmonic distortion are orders of magnitude greater in terms of the distortion generated than jitter. Jitter as a small number of signal correlated sidebands is worse than random (broadband) jitter which just raises the nosie floor. In fact if you compare the IMD and jitter figures for a sample of digital audo devices you see that the correlation between the two is extremely close. This would make me think that it is IMD not jitter that we need to worry about since it looks like IMD is a result of jitter. Bob Adams of Analog Devices suggested that you do not need to measure jitter as you will see it in oher distortions.

So then what level of IMD is actually audible and do many digital audio devices get close to this, the answer I get from the AES library is IMD is more audible than harmonic distortion but the threshold is in the order of 0.02% , what devices have IMD this high, er well not many actually, to the best of my knowledge only 1 DVD player and 1 music server are verifiably this bad, not even the PS1 is that bad, so why worry ?

 

[audioengr]

Quote:

Originally Posted by El Bishop /img/forum/go_quote.gif Thanks, Steve. So does the sonus produce superior sound quality (i.e., better than 16/44.1)? or is it just the functionality?

Functionality. Sound quality requires reclocking. All WiFi devices only do 44.1 except for Transporter. The Sonos does 24/44.1, which is bit-perfect, but lower noise floor.

Steve N.