Airport Express wav file vs CD played thru iTunes

I just bought an Airport Express and have it connected to my Primaluna integrated without using an external DAC (for the time being).

When I stream a wav file from iTunes the sound quality is noticeably worse than the same track played on a CD through iTunes. The wav file sounds compressed and very muffled. I would expect the quality to be equal to the CD. I only did this as a test and don't expect to play CDs through iTunes on my laptop streaming to the AE.

Will an external DAC "correct" this problem? Or is the wav file encoder for iTunes the issue? Or maybe something else entirely?
I think you need to use lossless/ACC files to get the same quality or close too as a CD. WAV, MP3's are compressed, look at the file size btw the two.

We have been ripping CD at lossless and yes they take up a huge amount of space but in comparing them to a CD the sound is almost the same (qualifying a bit)
WAV files are uncompressed and should be of the same quality as a CD, no?
I'm streaming wirelessly from iTunes on an iMac G5 through an Airport Express connected by glass toslink to a Benchmark DAC1 and then to my amplifier.

WAV files, which, as Arm said, are uncompressed, Apple Lossless files and AIFF files, which are what you find on CD's, are indistinguishable from each other. MP3 and other compressed formats don't sound as good, though MP3's at the higher bit rates aren't bad.
The one thing you have indicated that could be involved with the sound quality is when you indicate:

"is the wav file encoder for iTunes the issue?"

My question to this is are you ripping your CD to your computer using a WAV lossless file then importing this file into iTunes? While I am no expert on iTunes (don't much care for it personally), I thought when a file was converted and brought into iTunes it became an MP4 (which is compressed).

Perhaps I am off base on this, but I would check and confirm that you are bringing the lossless WAV file into iTunes (if there is any conversion, which I thought there was) using an Applelossless codec versus the standard MP4.

Also, I suspect that the internal DAC is part of the issue, but it sounds like you are already planning on doing something about this.
The difference is jitter. The stock AE has very bad jitter compared to a decent CD player or even a computer playing a CD. A reclocker can bring the performance of the AE beyond that of a good transport or CD player. Most audiophiles that are getting stellar results from Squeezebox, Sonos and AE are using a reclocker after it.

If you dont understand jitter, then read these papers:

Steve N.
Empirical Audio
Thanks everyone for the responses.

Steve N, I think you answered my question and the whole issue should be moot once I get an outboard DAC.

Ckoffend, I'm using iTunes for wav file encoding. I had read about others having issues with their encoder so I thought I would put it out there.

I guess I am a bit confused. I interpreted from Arm's first post that he was using the laptop with iTunes to play both the CD and the WAV file -which he compared. So wouldn't the AE's jitter apply to both media types, both are reaching the AE as a Apple lossless stream and then decoded there to analog?

Arm, please clarify if I have how you were playing the CD.

ARM - If you believe that a DAC is the solution to eliminate jitter, then you need more experience with DAC's. I get to hear a LOT of DAC's in my profession. They ALL need jitter reduction IMO.

Steve N.
Edo_musica - the CD is usually played directly from the laptop to a DAC, not through the AE.
Steve N.

Please elaborate on reclockers. I have iMac G5, AE, DAC. I wonder if PS Audio's upcoming Digital Lens is similar solution? Are there competing reclockers to consider? Please advise.

Eric - there are several anti-jitter units available, both old and new. The older ones were made by Audio Alchemy and also Genesis' digital lens (I believe did this). There are some modern day DACs that also incorporate jitter reduction and other DACs that depending on the transport can act as the main clock for the cd transport/player and of course there are also external clocks (such as the two by Esoteric). But for either a DAC or an External clock to work, one must have the appropriate connections and capabilities for them to connect to the transport/CDP. As a result, in some cases, you are getting into pretty big bucks with the clocking approaches.

From what Audioengr stated above, the AE has a tendency to create a lot of jitter. Perhaps there are alternative devices to the AE that may fix your problem more to your satisfaction - perhaps others that are more familiar with some such devices could recommend them here? Are you using the AE for wireless purposes?
Yes, I use the AE for wireless; but only for iTunes / AirTunes. No other usage such as internet / ethernet connected; not even using the usb port for a wireless printer. I'm using wired internet and another Airport Extreme Basae Station for wireless printing. So I'm experiencing rather excellent audio from my base station and have not yet seen the need to upgrade to say a squeezebox or adding a master clock / reclocker. I'm just curious as to how much more improved my system would sound with less jitter if even necessary. In dialog with Paul McGowan of PS Audio, I'm told a digital lens (upcoming) will definitely improve. However, since there is also an upcoming Ultra version of the DL-III, I'm sort of waiting on the sidelines before deciding / investing. Not to mention the also upcoming PWT transport. Isn't this a great hobby!