For $115, the 4.5s are a great deal. I can hear the amp hiss on mine about two feet away, so I just don't use them up close. They really do sound great, IMO.
Thanks! I just checked mine and I get the same thing - hiss (and 60Hz hum) in a quiet room that disappears right around 2 feet away when listening for it. I've used them a lot and had not noticed, my laptop fan (Lenovo ThinkPad i5) is louder.
FWIW, one of the reviews said if you get static/hum to ground the source.
It can use (unbalanced) RCA or (balanced) TRS 1/4" inputs. I don't know if a balanced input would eliminate the issue or not. I'm good with it as is.
Looking for other pros/cons:
Pro:
1) Headphone jack (on front).
2) The drivers have metal grills to protect them (I use mine as a portable speaker system, so this is handy).
Con:
1) They use spring clips for the speaker wire between the speakers which means bare wire ends (I don't like for travel since they can snag stuff - I put them in a separate pouch or just a baggie).
2) The speakers do not have a high pass filter to limit the low frequencies when a sub is connected (pretty sure no LPF either)
3) From a review I just read, it sounds like the BT range is only about 12-14 feet (he tried with 3 different sources). I have used BT, but had not challenged the range.