Originally Posted by alpina527
I have a 2008 E92 with premium sounds. I've just replaced the under seat subs with some SWS-8 subs and find them a bit boomy and lacking in mid bass.
These are the 4 ohm versions running through a 200w X 2 JL XD400 amp.
Can anyone out there suggest some good EQ settings.
Where are you crossing over the SWS subs? I used a 24dB/octave filter at 110Hz, and then boosted to 200Hz band on the eq to the max. Seems to fill in the hole left by SWS somewhat - not awesome. Female vocals don't really grab you by the balls, but I can live with that.
The green trace is the line level output from the sub channel on the EPS system. You can see where it roles out, giving you an idea where the midrange 4" speakers crossover points. The blue is an RTA trace from my system with the SWS subs (500w mono), but without any EQ tuning (except for what I was able to do on the sub channel through the 3Sixty to fill in bass holes).
You can see the mid-range hole from 100-200Hz. Before you get crazy and buy new subs, one thing you might consider is playing with the OEM subs a bit more. It could be that the stock tuning was conservative and that you could achieve more if you had control over relative volume (you own amp) and bass eq under 100Hz.
One issue I have with a second sub system is the weight it will add to the car. If that's not an issue for you, then that may be the best way to go in the long run.