Arrows do make a hissing or sizzling sound in flight, and bowstring noises vary quite a bit, although it's my understanding that the loudest sound a bow makes is the arrow striking the target.
I'm no archery expert, but I grew up with bows and guns, I just haven't had a lot of time to do either due to my circumstances, that's life... It's been a while since I've been to the archery range, but in my experience all bows put out roughly the same noise level: recurves (creak then fump) compound bows (less creak more fump), or simple bows (no creak all fump).
The noise, in flight, comes from the fletching which is widely varied based on the material. Synthetic feathers make the most noise, from what I remember, (cheapest is always loudest with arrows) but it's still very quiet, especially so when compared to the sonic boom of a bullet cracking by your head.
You're correct on the impact sound on hard targets, but not on soft ones. On hard targets. that it doesn't blow through. (e.g. trees - hopefully) the composition of the arrow makes the sound: natural materials crack and shatter with high-weight bows otherwise it's a little bit of a warbling sound, while synthetics undulate wildly (sometimes it almost sounds like a red-neck guitar). Even ricochets don't make a lot of noise, it's a quick scraping sound, until it sticks, breaks, or loses momentum, in which case synthetics can be the loudest, if the arrow's fiberglass not aluminum, but it's unlikely to happen (it was more likely that I broke the head and/or lost some fletching in those circumstances). In soft materials it's more likely that the target will be making the noise... Otherwise "softie" absorbs all the vibrations and, on high-pull bows, the arrow can completely penetrate through, if it doesn't ricochet inside the target (dang them bones).
Overall it's still very quiet with low pitch noises, and most of the time you get two shots before wildlife catches on. Maybe the future even has stealth arrows???