M4a77TD audio review: VT1708S High Definition sound card

Built into the ASUS M4a77TD motherboard is a 8 channel sound card using a VIA chipset (VT1708S).  It supports up to 8 speakers, microphone, and line in.

Audio playback is nice an clean, with zero background hiss/hum while music is playing back. Due to aggressive power saving mechanisms (the VT1708S is also meant to be used in laptops), if no sounds play for a couple minutes it shuts off power to the speakers, resulting in a loud hum/hiss. This is fixed immediately by playing some music, adjusting the mixer volume, etc, but is super annoying.  There is an easy work-around, however: use the Windows volume control (sndvol32.exe) to mix in just a little bit of sound from MIC or Line In to the output. The sound card doesn't check to see if any actual sound is playing on Line in/MIC, but assumes that there could be and shuts off power saving. I could only figure out how to do this with the Windows Volume control - the VIA mixer (HD Audio Dec) doesn't seem to expose this functionality (edit: it does - click the button below the volume slider to un-mute, and the white arrow at the lower right to show line in, etc.).

The VIA mixer/control panel is ugly, but usable. It attempts to look cool by visually modeling itself on a stereo, but just manages to look clunky and reduce usability. It does allow you to control the sound card's built in equalizer, which might be useful if you don't have a stereo and just plug the output into a cheap set of PC speakers.

It also offers a set of customizable hot keys to increase/decrease volume, or mute, in case your keyboard doesn't have that built in.

Meanwhile, the software takes ~14MB of RAM, and 32MB on disk. What a hog. SndVol32, in comparison, uses just 3.5MB. And keep in mind Microsoft isn't exactly known for efficient coding.


Recording ability is miserable. The MIC amplifier (even with "MIC BOOST" turned on) is way too weak, even when using a reasonably good quality $25 radio shack hand held mic. The frequency response isn't too good as well. The high frequencies are quite attenuated, even when recording a painfully loud, high pitched bell. The sound card does better recording from itself - if you set the audio input to stereo mix, and max the volume of every knob you can find (output and input) then you can get 45% of the dynamic range possible with a 16 bit recording. Which is to say, still not very good, but usable in a pinch. The frequency response appears to be fine in this mode - the recording is quiet, but not distorted.

You wouldn't buy this MB expecting to set up a home studio, obviously. But it is not too much to expect that your MB would be good enough to use with Skype. This does not seem to be the case. Very disappointing.

You might think that you could just slap in any old PCI sound card to rectify this problem - like an old Sound Blaster Live, but keep in mind that the PCI slots all use shared IRQs, so pick your sound card with care (the sound blaster live does not work in this MB).