Hi,

i've read this thread and have to say that from an electronic view it's no good idea to only use a capactor in the signal chain. This can harm your amp, because of impedance peaks. It would be much better to use a standard circuit for freqency response leveling. This contains a capacitor, a resistor and a coil.

I've found a tool on the internet where you can simulate the freqeuncy response leveling. It also shows how to wire and what will be the right values for the electronic components (approximate values).

From my experience i would recommend a leveling of -3 to -6dB at approx. 150 hertz.
Personally i prefer the -6dB version. But that's a matter of taste.

Here is the link to the tool: Strassacker: Lautsprecher - Boxen - Selbstbau
The front mid woofers have an impedance of 4 ohm (RE = 3.4 ohm)

Regards
Markus