I'm jumping into this conversation a bit late but...
I just ordered a pair of Infinity Primus 363s a few days ago...The only ones I've really ever owned were good for loud volumes and that is about it.
If, by this you mean you want speakers you can listen to at lower levels, the P363 are probably one of the better candidates. The little extra bass they have will sound rich and full whereas a totally flat speakers will sound anemic in the bass department at low volume.
As you can see in the chart below, at lower levels, the bass really needs to be much louder for us to perceive it as being the same volume:
Now the thing that concerns me is that they are advertised as an 8 ohm speaker but this review clearly concluded it as a 4 ohm speaker. I have a Scott 390R receiver that will be powering these speakers. Anyone think this would be a good match or did I mess up?
I don't know that particular receiver, but I do know the Scott gear from the late 60's and early 70's was very nice. Late 70's may have been very good as well, but I know by the late 80's the brand was producing crap and milking the good name for all they could get out of it!
However, you are talking about 35-40 year old gear, so unless you have replaced the capacitors, it may not be well suited any more.
Moreover, about this statement you made:
If I retain my old speakers into the B and C channels
That is pretty unique to have provisions to connect three pairs of speakers to a receiver! Unless you have details on the rigor of the amp section, I would discourage you running 2 pairs of speakers at once. If you do this, you are cutting the impedance in half, so that place where the P363 drop to 4 ohms, the receiver may see as low as 2-3 ohms!
I love the look of the old gear. Wish we could get new gear in silver in the States!
