Hi!
I've tried to search a bit here and there, but can't find out what makes ASIO superior to direct sound. Could somebody please enlighten me? 
Not being an expert, ASIO is a another driver model for those Windows OSes that support it. It was designed from the ground up as a low-latency, professional-grade framework for recording and other audio operations by Steinberg.
It's primarily advantageous if you are running WDM-based drivers in WindowsNT and 2000. I don't know about XP. The Windows 9x (& ME) family use a diffferent driver flavor called VxD.
At least in Win2k, the problem with WDM drivers is that it passes all audio information through something called the KMixer. This "wonderful" piece of software would automatically downsample the audio & add latency into the playback. Basically, it downgraded audio quality.
The VxD drivers don't have the KMixer, so audio applications frequently sounded better on Win9x, etc. than on the flagship OSes.
ASIO allows applications to bypass KMixer and send the bitstream directly out of the card. I notice a difference in the sound quality when using ASIO and my M-Audio Dio 2496 on Win2k. Also, it allows uncorrupted bitstreams to pass through--eg. DTS CDs.
There is more information than you can shake a stick at on this subject over at the AVS Forums:
http://www.avsforum.com/avs-vb/Best,
Brad
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Topic: What's the big deal about ASIO? (Read 1736 times)