I have built a MTM center channel with two 5″ Morel CAW538 woofers and 1 Kartesian TWt30 tweeter. The two woofers are 8 ohms so if I put them in parallel, the impedance dips down below 4 ohms between 120 and 220Hz and hits a low of about 3 ohms at about 175Hz. My amp, the Adcom GFA 7000 is rated down to 3.2 ohms. Would this be a problem? If I put seven 3.3ohms resisters in parallel and connect them in series to the woofer, it brings the impendence up to 3.6ohms at the lowest point, still at 175Hz. Is adding resisters just a bad idea? If I understand correctly, it does lessen the amps ability to control the woofers, but they will be crossed over by the home theatre receiver at 80Hz, so I am not sure if that is a big issue in this case??
I know I can wire the two woofers in series, but then I end up with decreased bass, causing me to have to had a fair amount of resisters to the tweeter to bring it back down, making the speaker not very efficient, especially when compared to my front towers. So I guess my main question is, better to wire in series and just increase the level of the center channel to match the towers (while having a very uneven impedance with multiple spikes over 20ohms ), wire in parallel with a dip down to 3ohms, or wire in parallel and add the resisters?
I did try changing the inductors values on the woofers and changing from 2nd to 3rd order, but could not get ride of the impedance dip without ruining the frequency response.
Thanks in advance for any help.