It's not just beeps (I might be imagining those rather than remembering them) but pretty nasty static.
So it's a common fault with cheap PCs? That's a bad show for a >£1000 machine.
What do you mean by going digital exactly? Bluetooth headphones? I really like my Sennheisers so it's pretty disappointing.
It can be static, a fizzing, the aforesaid rapid blips, etc. Even the Pro has an inferior soundchip in terms of analogue performance in comparison to some competing
workstations (where audio performance could be hardly said to be critical, unlike the use many Pros would be put to).
Going digital is using a DAC (digital to analogue converter) or a home-theatre receiver - or if you're feeling fancy,
a pair of headphones with built-in DACs (not bad actually) - from the built-in optical digital output of Intel Macs (Pros have separate outputs, others have combined line out / optical out jacks). While the sound capabilities of the chips are once again not that great, the digital output will get the most out of it without extraneous blips, fizzes or scrunchings. The other alternative is as I said an external soundcard.