Wednesday, February 07, 2007

Wireless Stereo!

Ok, we've all heard of Bluetooth, and should be relatively familiar with what it is.
Its a way to connect devices without wires, right?

Well, bluetooth is only as good as the devices that are released to take advantage of it.
The most common use is in wireless phones, where it can be used to connect to a handsfree headset, or sync with a nearby BT-enabled computer. But the potential goes far beyond that...
One day in the future, it would be nice to not have ANY wires on my desk at all... my monitor, speakers, printer, keyboard, mouse, scanner, webcam, etc... But that day has not yet come. While many of the devices on my desk can (and some are) wireless, they still haven't perfected the technology to a point that it can replace EVERYTHING, at least not easily. As of yet things like a video monitor feed over bluetooth aren't practical, and until recently, the audio quality of Bluetooth wasn't on par with wired stereo speakers.
Luckily, they're always adding new profiles, which are basically standards to attach to new kinds of devices.

The latest buzz in Bluetooth has been a serious upgrade to audio quality. Originally designed to carry little more than a monoraul phone coversation, people have expressed a great interest in having HiFi digital stereo sound over bluetooth. They call this profile the Advanced Audio Distribution Profile, or A2DP for short.

This allows for music lovers to be free of the wire tangles that many enthusiasts hate to deal with, not to mention you don't have to actually have your music player on your body... rather simply be in the same room as it. *

This also opens up new doors to convergence devices... many A2DP headsets such as the Motorola pair pictured here support both A2DP and the older audio profile designed for phone calls. With its built in microphone, you could listen to music and not be afraid of missing a call that you couldn't hear... the music will automatically pause as the headset switches profiles to allow you to hear a ring and answer the call. When you are finished, it will go back to where you left off.

Now, for you Windows Mobile enthusiasts who are reading this and wondering why I bring this up, here's my good news / bad news.

The good news: Microsoft started adding the A2DP profile to their bluetooth stack in newer versions of WM5 (aku 3 and up), and there are hacks available which will enable it in the older AKU's as well.

The bad news: MS's encoding algorythm stinks!
A2DP requires the sound be encoded using a system called SBC. For some reason, the way MS programmed their encoding, it creates an awful distortion on certain frequencies that are clearly audible with certain headsets.
For example, an I-tech R35 headset will play a very irritating hiss/ringing over vocal sounds when using a Windows Mobile device. However, these things sound great when paired to my PC's bluetooth which uses the Widcomm Bluetooth drivers.
Many headsets play the distortion differently, it may be more apparent in some versus others. Some won't even exhibit it at all, as is the case I found with a pair of Logitech Ipod headphones (designed to be used with an ipod adaptor, but can be paired with another BT device easily).

This is a serious problem for those who spend a lot of money on wireless headphones to find the quality is sub-par. Stay tuned for updates... hopefully MS will fix it in a future service pack.

* Theoretically, you only need to be in the same room (within 30 feet) of a Bluetooth device to stay connected. However, in practicality, many people find that a2dp requires you to stay a bit closer.