Do you have any crossovers on your 6.5 speakers? Are they stock? We need a little more info about your setup. What vehicle? Sealed or ported box? What kind of power wires are you using? What amp? Something seems really wrong to not hear your bass with 1000-1300w.
on your headunit, you need to set the hpf to 80-100...that will keep the 6.5s from playing lower frequencies like you are experiencing right now
So lowering the EQ frequencies above 80hz doesnt work? Lower 200hz, 400hz 1khz 2.5khz 8khz and 16khz to -10 db and build your EQ curve from there and raise up the volume or else you arent getting anywhere close to the 4V pre-out your head unit is suppose to make.
again. Need a multi meter. You need to put it on your amp terminals and play your hardest hitting song and see how low your voltages are dropping. If they drop below 12.6v then you need electrical upgrades. If they still are above 13.8 volts, you can easily add another 4 channel amp without any stress or issue to the electrical setup.
Pretty sure adding the 4 channel will be okay for your setup. In actuality even after you add the 4 channel amp, as long as you are above 12 volts, its fine, its just a threshold where you would want to look into upgrading electricals before going any bigger.
150 x 4 would be the cap for class D. 125 x 4 would be the cap for class ab
