[Jacques]

Is it just me or is the Octane's sound quality far superior to that of the O2.

I'd go so far as to say it's better than my Mac Pro's sound. It sounds really clean and crisp, wheras the O2 sounds a bit hissy and almost filtered.

Do the two systems have significantly different hardward audio wise?

[stormy]

According to what I can find they both use the RAD audio processor. But the issue is whether you're using analogue output or digital. If you're using the analogue output it will depend on the quality of the DAC chip they used on either model. If you use coax/spdif output then you can have your own external DAC instead.

https://bukosek.si/hardware/collection/sgi-octane.html
https://bukosek.si/hardware/collection/sgi-o2.html

[commodorejohn]

Just curious, are you using the internal speakers, or hooking them to external gear? I've long wondered just how much effect the case has as a low-pass filter/resonant chamber when using internal computer speakers; seems like in my experience, going all the way back to the Mac IIcx I grew up on, it's pretty reliably the case that larger computers with more open interiors and heavier external walls work better to deaden unpleasant high-end junk while giving the warmer frequencies room to breathe.

[Jacques]

This is just 'testing' using a) a pair of Sennheiser headphones connected to the stereo jack and b) playback via phono cables to a NAD 3020 stereo amp and a pair of Bowers & Wilkens speakers. Test file is a lossless encoded, normal stereo audio file.

both machines have had the audio ports cleaned but still, the Octane just sounds better, almost more 'open'

[Irinikus]

The octane probably has a better DAC and analog output stage.

Let’s face it, the Octane was more of a high end machine than the O2 was.