Logitech?
Really cool!
In my opnion, normally the music is coming from the front.
So the rear speakers will not louder than the front speakers.
Do not expect that there wiil be some strong bass from the 6x9 speakers.
I have tried JBL P-9633 and Polk Audio db691.
JBL P-9633
# frequency response 25Hz-22kHz
# RMS power handling 100 watts
# peak power handling 250 watts
# sensitivity 92 dB
Polk Audio db691
# Frequency Response 35Hz-22kHz
# RMS Power Handling 100 w
# Peak Power Handling 300 w
# Efficiency 93 dB
They both don't have strong bass.
(I don't use a amplifier.)
Maybe the bass will be stronger if you use a amplifier?
I don't know.
Just my experience.