I doubt there is anything wrong with the 803S's, but you're right in that there will be a "Magic" placement. However, everything else in your system will affect the sound that is "best for you".
I have 802D's and drove myself crazy until I got the sound I was after. Ended up with Class D amps (to feed the beast), and an ARC tube preamp. I use silver interconnects amp to preamp and everything in the phono circuit. However copper to the DAC and copper speaker cables. Bi-amping made a significant improvement. High pass filters built into the amps kept the highs quiet.
It takes time and effort but you'll get it worked out.
Paul
I have 802D's and drove myself crazy until I got the sound I was after. Ended up with Class D amps (to feed the beast), and an ARC tube preamp. I use silver interconnects amp to preamp and everything in the phono circuit. However copper to the DAC and copper speaker cables. Bi-amping made a significant improvement. High pass filters built into the amps kept the highs quiet.
It takes time and effort but you'll get it worked out.
Paul