Stuttering Audio Fix for Asus EEE 1000HE

The not so new EEE PC was experiencing intermittently stuttery audio when playing a Flash based radio stream. This was strange as it coped fine with MP3 and WMV streams, even with video. It wasn’t a buffering issue. The audio had very short glitches – the kind of thing that happens when a device driver locks the bus too long (he says, having worked on a Linux audio driver a few years back).

The wireless drivers were up to date and the wireless hardware configured to use CAM mode (a problem that plagued the ION HTPC when I first installed XP on it). Power management settings were set for high performance.

I also determined it was no where near running out of CPU, sitting at only 10% when playing the stream. After updating drivers, firmware and minimising the configuration as much as I could, I started thinking it might be network related.

I set up a regular ping of length 8192 bytes from my workstation to the EEE so I could see what network performance was like. I was only half surprised to find that ping times were all over the place, with some peaks in the 100s of ms. With the audio streaming, the high peaks corresponded with glitches in the audio.

With it happening even when close to the WNDR3700 wireless AP, it wasn’t a signal level problem. It was connecting at 130mbit (N speed) on the 2.4GHz band.

I switched the router to limit 2.4GHz to 54mbit and the audio problem went away. Ping times to the EEE became a solid 4ms.

Looks like its a combination of crappy behaviour for the EEE’s wireless driver in “N” mode and the Flash Player using a very short audio buffer, making it easy to underrun audio playback. Fortunately I can handle the slower 2.4GHz network since I run a separate 5GHz network for the HTPC.