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Getting in Tune with AirPort Express

by Michael Brewer
11/12/2004

Back in July, Apple started shipping the AirPort Express, what they're calling the world's first 802.11g mobile base station. It's a neat little device. Quite unimposing at a little larger than an iPod, it has a stark white appearance making it look like Apple's version of the monolith from 2001: A Space Oddessy. There are three jacks on what I will be calling the bottom of the device — although there is no obvious up or down as far as the device itself is concerned. It has USB, Ethernet, and headphone and mini-optical jacks.

AirPort Express

Setting It Up

This is the first bit of Apple hardware where I actually installed software before setting it up — I even had to reboot afterwards. Mac OS X Panther comes with AirPort Admin Utility and AirPort Setup Assistant, but not AirPort Express Assistant (of course this device didn't exist when Panther was released). So Apple includes a CD with the AirPort Express hardware that contains the AirPort Express Assistant, iTunes, and other AirPort software. If you're a Windows user, you won't get the assistant and will have to use AirPort Admin Utility.

The first thing you need to do is connect all of the cables to the AirPort Express (I connected a headphone-to-RCA cable for my receiver and a USB cable for my printer). Then, plug it in and turn it on. It'll start up right away.

The assistant makes setup very easy. It walks you through the steps with a good amount of explanation. It first gives you the option of creating a new wireless network or connecting to an existing one. If you will be connecting the AirPort Express to your network via Ethernet, you should create a new wireless network. Since my purpose for getting the AirPort Express is to have a way to stream music to the sound system in my living room, I opted to connect to my existing Linksys-powered wireless network.

AirPort Express Assistant finds the wireless network the AirPort Express created when it started up and connects to it after confirmation that it is the correct one. Since I decided to connect to an existing network earlier, I needed to specify the network to which it should connect. It also asked to name the AirPort Express and gives "Living Room" as an example, which is what I used.

At this point, the assistant goes about securing the AirPort Express. It prompts the user for a password that will be used in the future when changing any of its settings. The last step is to confirm the settings and update the AirPort Express. It was a very painless setup, and I was able to mate my Apple AirPort Express with my Linksys Wireless-B Broadband Router without any trouble.

Streaming Sound

After completing the initial set-up, I switched to iTunes to start playing music from my PowerMac in the home office to my receiver in the living room. iTunes will automatically recognize the AirPort Express by Rendezvous. The AirPort Express will be displayed in a drop down list along with an item for Computer. If you have multiple Expresses, each will show up in this list with their own given name.

Itunes automatically recognizes the AirPort Express

I performed some benchmarks while playing music in iTunes on my PowerMac Dual 2Ghz connected to the rest of my home LAN wirelessly. Before I performed my tests, I went to iTunes' Audio preferences pane and turned off Crossfade playback, Sound Enhancer, and Sound Check.

The results were surprising to me. I expected the transcoding from AAC to Apple Lossless (the codec used to transmit sound to the AirPort Express) to have consumed more cycles than it did. I averaged 5.13% CPU utilization in iTunes while playing 128 kbps AAC over AirTunes to the AirPort Express. In comparison, playing those same songs on my computer required 3.9% of my CPUs. Playing those same songs locally again, but this time with Sound Enhancer on and turned to high, used 4.37%.

My testing also revealed why Apple chose to develop their own lossless codec instead of using an existing free codec like FLAC. When streaming 128 kbps MP3s to my AirPort Express, the CPU utilization jumped to 20.17%. Wow. I'd previously thought that Apple's reason for inventing their own lossless codec was because of packaging concerns inside of the AirPort Express that may have meant FLAC would require more processor power than the Express provides. Apparently, they were more concerned about the hit on the computer.

Since Apple has promoted AAC as their preferred codec, they needed a lossless codec that could be cheaply transcoded too; Apple Lossless is evidently the result. I'd still like to see Apple open up Apple Lossless so that it could be used on other platforms. It'd make me feel much more comfortable about using it as an archival format for some of my out-of-print albums. Also, it would mean people on systems other than Mac or Windows could inter-op with the AirPort Express.

Streaming Showdown

Song Codec Playback Enhancer First Second Third Average
Neon AAC AirTunes Off 5.40 7.10 4.40 5.63
Rhapsody in Blue AAC AirTunes Off 6.40 3.00 6.70 5.37
Wonderful Place AAC AirTunes Off 3.20 4.10 5.90 4.40
Aggregate Average 5.13
Galleons of Stone ALE AirTunes Off 5.80 4.70 2.20 4.23
Getchoo ALE AirTunes Off 6.30 4.10 7.00 5.80
Paranoimia ALE AirTunes Off 6.80 4.60 4.90 5.43
Aggregate Average 5.16
5:15 The Angels Have Gone MP3 AirTunes Off 17.70 17.90 21.50 19.03
As Soon As MP3 AirTunes Off 22.40 25.50 18.00 21.97
Back To You MP3 AirTunes Off 20.40 18.60 19.50 19.50
Aggregate Average 20.17
5:15 The Angels Have Gone MP3 Local Off 5.70 4.60 4.70 5.00
As Soon As MP3 Local Off 2.20 3.60 2.50 2.77
Back To You MP3 Local Off 2.80 4.40 5.30 4.17
Aggregate Average 3.98
Neon AAC Local Off 5.10 2.80 3.60 3.83
Rhapsody in Blue AAC Local Off 3.00 4.50 3.90 3.80
Wonderful Place AAC Local Off 4.00 5.20 3.00 4.07
Aggregate Average 3.90
Neon AAC Local On 6.50 3.60 3.50 4.53
Rhapsody in Blue AAC Local On 4.50 5.50 3.90 4.63
Wonderful Place AAC Local On 4.10 3.90 3.80 3.93
Aggregate Average 4.37

The Experience

I've hoped that Apple would release a product for the living room from even before the iPod was announced. I envision something about the same size and shape as an average DVD player with a G4 or better microprocessor in it — something that can excel at all of the audio and video encoding and decoding that'll be thrown at it. Apple could easily take their new iMac, remove the screen, and rearrange the ports while adding a few more ports. They would come up with exactly what I've been hoping for as well as something that'll settle the enthusiasts who are pining for a low-end headless desktop from Apple.

But Apple hasn't done that; they released the AirPort Express instead. I had been leaving a docking station for my iPod in the living room, but the AirPort Express seemed more attractive than that, so I sprung for one. I've got the AirPort Express setup behind my HDTV in the living room with sound running to my receiver through a headphone to an RCA patch cable and with a USB printer attached.

My PowerMac is located in the home office in the opposite corner of the same floor. It isn't too difficult to walk over to my Mac to control what is playing, but I usually just stick it on shuffle by album or song and leave it alone. The way I listen to music on my iPod and the way I listen at home are different, and having the AirPort Express alleviates that. My iPod seldom has complete albums. Shuffling by album on it can be jarring when the song you're expecting to come up next is skipped over. And when I shuffle by song at home, I typically use it as background music instead of active listening, so I like to cross-fade the playback of one song into the next. The iPod can't do this either — yet.

I like to be able to log out of my account when I'm not using it and yet still let the music play. So, I created a user on my computer strictly for playing music. I rarely use it, but it is there for the occasions when it comes in handy, days when the wife and I are both using the computer but we both want to be able to control the music without having two instances of iTunes fight over who gets to stream music to the AirPort Express. Rendezvous music sharing makes this easy, but a shared music library with user- specific meta-data would be the ideal solution. Maybe we'll get a Spotlight powered version of that in iTunes 5.

The coolest thing yet was being able to unplug the AirPort Express from the living room, take it outside, and plug it into a stereo to provide music for a cookout I had. I was able to quickly create a playlist of songs in iTunes for the occasion, and with cross-fading enabled, we enjoyed hours of non-stop music. And I didn't have to touch a thing on the AirPort Express; I just had to hit play in iTunes.

Homogeneous Apple

I got an AirPort Extreme base station while I was writing this review. I bought it because I wanted to use WPA encryption and 802.11g. A side benefit of having the AirPort Extreme base station is setting up the AirPort Express to expand the range of the base station in a wireless distribution system (WDS). A WDS has its own obvious benefits.

But, the cool benefit for me of using the AirPort Express as part of a WDS is that I can connect my Thinkpad to the Express with an Ethernet cable and connect to the internet over the Express' connection. Since a lot of people are going to place their AirPort Expresses in their living rooms, I could see these same people setting up wireless distribution systems to enable connecting their video game consoles to the internet. If I ever get the broadband adapter for my PlayStation 2, it's what I'll do. The drawback to setting up a WDS is that I can't use WPA and have a WDS, so I am resigned to using 128-bit WEP.

Final Thoughts

AirPort is by no means the perfect solution for streaming music on a local network. But it's darn good. One of the early improvements that I'd like to see is the ability to stream music to multiple locations at the same time. As Apple continues to refine this technology, we'll discover more ways to enjoy and share our music libraries. But for now, I must say that I'm hooked.

Michael Brewer is a developer based near Charlotte, North Carolina. His interests include web development of various flavors, databases, and Java. One of the off-shoots of these activities is his website Brewed Thoughts.


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