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      07-04-2011, 06:10 PM   #7
jml's Avatar

Drives: E90M3
Join Date: Dec 2008
Location: Austin, TX

iTrader: (2)

Originally Posted by VP Electricity View Post
I too am very confused about why you would lowpass the underseat woofer at 110 @ 24 when you have a 4" midrange highpassed, per your chart, around 250.

alpina527, I agree that I would not use the amp's lowpass filter in your situation.

@ jml - Per your chart the EP lowpass F3 is around 250. I'm not clear if the blue line is acoustic (with a mike) or electric (how you describe the green line). But given how closely the blue and green lines are mapping each other up to 200 Hz, they have to be the same. These measurements do not resemble the measurements I recall in a 2011 M3 w/EP - I will have to see if I saved the screenshots.

Look, we are using somewhat absolute terms for a relative difference. Many people use the SWS and do not find them lacking. One of the contributing factors is what they listen to. Other folks can't stand their sound, and that too is a factor of what they listen to.

alpina527, what are you listening to?
Blue is via an RTA mic positioned at head height on the drivers side (E90). Green is direct from the LOC (I obviously messed around with the level to get it visible on the same graph).

Running the SWS over 110-120 sounded pretty bad to my ears. It's clearly not designed to maintain accuracy in that region. Lots of harmonic distortion. So I pushed the OEM 4" drivers to try to cover it by boosting 200Hz in the OEM eq. It sounds good enough that I'm not motivated to add more weight to the car.