What exactly is Airport Express and AirTunes?

Question

Sounds like a system to send music wirelessly to any HiFi... Is that right and how does it work/what do I need? Would an audiophile be satisfied with the quality of sound? i.e. is this something that would be out of place on a high end audio system or more suited to the more usual integrated stereo systems?.
I am using an Apple TV as a music source and just wondering whether the Airport is a possible alternative.
Does the airport also transmit video?
Thanks!

Answer 1

Sounds like a system to send music wirelessly to any HiFi... Is that right and how does it work/what do I need?
The AirPort Express Base Station (AX) is a combination NAT router, wireless access point, print server, and a target device to receive AirTunes audio streams.
AirTunes uses the Remote Audio Access Protocol (RAOP) to stream music to the AX. RAOP is based on the Real Time Streaming Protocol (RTSP) but with an extra challenge-response based authentication step.
For audio playback, you would need the following as a minimum:
o An iTunes host with with either wired Ethernet or wirelessly capability.
o Powered-speakers or an audio receiver with either analog RCA or digital/optical inputs.
o Either a 3.5 mm minijack-to-dual RCA or a 3.5 mm TOSLINK cable.
Would an audiophile be satisfied with the quality of sound? i.e. is this something that would be out of place on a high end audio system or more suited to the more usual integrated stereo systems?
For the AX, the audio is handled by a Texas Instruments PCM2705 digital-to-analog converter which it outputs on a 3.5mm stereo minijack. However, the innermost end of the 3.5mm jack is an optical S/PDIF transmitter.
The AX works only with iTunes v4.6+ and is limited to music files that iTunes can read; ie, 16-bit data only. (An exception is you can use a third-party product like Rogue Amoeba's AirFoil to stream other non-iTunes sources.) These data, though, can be in any file format that iTunes recognizes, from lossy MP3s at the low-quality end of the spectrum to Apple Lossless and lossless AIF or WAV files at the high end. It is also important to note that the AX functions only at a 44.1kHz sample rate. When you play 32kHz or 48kHz data, iTunes sample-rate-converts the data in real time before sending it to the AX.
iTunes uses a QuickTime CODEC to convert audio files to Apple Lossless, and then, uses AirTunes to send them to the AX. In turn, the AX uses built-in software that converts the Apple Lossless to an Encoded Digital Audio format. From there, digital audio is sent to a optical transceiver to convert the electrical signal to an optical one before sending it to the innermost part of the audio port. For analog, the AX has a built-in DAC to convert the Encoded Digital Audio to Analog which is sent to the same audio port.
I am using an Apple TV as a music source and just wondering whether the Airport is a possible alternative.
Unlike the Apple TV, the AX has no means of storing audio content. It is only a "relay" between the iTunes host and the sound playback device. Note: With the latest firmware update, the Apple TV can now use AirTunes to stream to an AX.
Does the airport also transmit video?
No. There are no video CODECs built-in the AX.