AirPort Express Sound Bites

Axiom: The Swedish are the most audiophiles in the world. And they have the best broadband prices, too!

Having an AirPort Express is not only great, it can be insanely fun, too! We received our AirPort Express and an accompanying little 5.1 Digital Sound System this week, which made me spend some time on exploring the possibilities.

Especially the fact that DVD Player does not yet support AirPort Express is a reason to searchfor reasonable ways to listen to 5.1 Dolby Digital or even DTS sound. Obviously, there are limited options when all you own is a shiny tiny 12" PowerBook: You need some kind of digital output.

The Options#

There are currently two reasonably priced items on the European Market that promise digital output via the USB plug:

• Creative SoundBlaster MP3+
• M-Audio Transit USB (Follow-up model of the “Sonica”)

The first is priced at CHF 80 while the latter can be bought for roughly the double. So, I bought the SoundBlaster MP3+ after two vendors in “Mac” stores told me it will work with OS X. I had my suspicions, but the urge to enjoy 5.1 Digital Video was greater and so I believed them.

But how do you test a 5.1 decoder if the only source of digital streams is the device under test?

AirPort Express to the rescue#

In a technical note, Apple explains how to stream DTS or Dolby Digital (DD) encoded sound to an AirPort Express that is connected to a DTS/DD decoder via AirTunes. Great! That would let me test how 5.1 Surround should sound – and how the SoundBlaster MP3+ did in comparison.

This sounds great, but again – where to take DTS sound from? A DVD obviously won’t work and I don’t have the Studio Equipment to test or produce that kind of music. So, Google to the rescue!¹

Lo, behold! It turns out there’s this little company called DTS that markets the DTS sound system to theatres, consumer products manufacturers and others. Not much interesting stuff there² – except for one thing.

Enter: The Swedish!#

At the very bottom of the file, I discovered this: The Swedish Radio provide DTS encoded files for download!

Radio? Yes! They have a whole area where you can find DD and DTS encoded sounds, ranging from classical concerts to radio plays.³ Wonderful! But its getting better:

Not only do they provide the aforementioned “classic” radio broadcasts, no, their library contains a whole lot of “test-data” that can be used to test the equiment etc. Exactly what I needed. They also have an archive with more stuff!

From all the available samples, the “Norway Demo” seemed the most suitable:

Norway Demo

This is our first clip in DTS-ES, 6.1 Discrete. It was played for the first time at the Nordic Soundsymposium in Bollkesjo, Norway. Norway VS Sweden in a bloody battle.

And the test shall begin!#

After I’d downloaded the 66MB wav file, I was ready to give my Sound System a try! I set-up iTunes accordingly, connected the AirPort Express via the optical link to the decoder and pressed “Play”.

Whew! When my wife heard it the first time, she just said «We won’t go to the mvoies anymore, do we?» It was plain fun – and not only because of the sound quality or the sound effects! Just give it a try if you can!

The result#

Now, we shall not forget that the intention of this test was to see, how well the decoder and the USB soundcard worked together!

As we’ve seen, our reference implementation worked well! Full 5.1 Channel DTS sound. The result for the SoundBlaster MP3+ however, was dim: I had the impression that the vendors “followed the spec” like the first category of programmers in Mark Pilgrim’s “ Why specs matter”.⁴

The device worked, it sent out a digital stream, but because these guys at Creative don’t know how to write drivers for Mac OS X, you only get the simple stereophonic representation (re-sample) of the DTS stream from a DVD. It’s digital, yes, but neither DD nor DTS.

(Fortunately, the decoder is quite clear about this: It displays exactly what kind of digital stream is at the input, so I have evidence for that!!)

Even worse: Playing the DTS tune I used for testing AirPort Express and the decoder over the SoundBlaster produced what you’d expect from a digital stream: random noise. Definitely no digital output!

Well, I should’ve known it. I will bring the SoundBlaster back today and buy an M-Audio Sonica or Transit USB, so we can finally enjoy the full fledged DTS sound of “Finding Nemo”. Hi, I’m Bruce.

I hope that Apple eventually will release the proper DVD support for AirPort Express but in the meantime, my wife and I will enjoy both the wireless radio broadcasts from our Macs and the stunning sound of Digital 5.1 surround.

A final note#

This article is once again powered by “ Bö”. It’s a great tool made by a great hacker! Thanks!

And I hope you agree with my axiom once you’ve tried the samples for yourself!

Update: Fun for all!#

For all those of you who can’t stream DTS/DD surround sound to your Hi-Fi tower and would nevertheless have some fun with the Swedish Radio, go and grab you a copy of VLC, the Video Lan Client. It is free and has an embedded DD and DTS decoder and will play the wavfiles without complaints as ordinary 2.0 stereo. Of course, you will miss the special effects, but there should be some fun in for you, too!

Oh, and: Never touch that switch again! …