melorib
Lowrider
It is very complicated to do what you ask, to measure it has to be upside down, not possible with the EL34 on, so not possible to switch on without resorting to kamasutra... 
The bass problem is not with the subwoofer, I think, it is above those frequencies, just sounds less sharp than before...

The bass problem is not with the subwoofer, I think, it is above those frequencies, just sounds less sharp than before...