So I had a 12" W3 (2 ohm) JL Audio sub installed yesterday evening in my e60 with logic7. After much tweaking I have to say I'm pretty dissatisfied. I feel like the sub hits too hard. I had a W1 in my e39 and I thought it sounded great.

The setup goes like this. I have the Alpine M-500 (500 @ 2ohm) its sound input leads are coming from the woofer through a line convertor. In addition I have a gain control knob inline between the Logic7 AMP and the Line convertor.

I'm not sure if the W3 is supposed to hit that hard and if so what are your thoughts of a W1 providing more "filler" bass and less sub thump in?

Additional Tweaking: The first thing I did was tweak the gain on the amp so that it's pretty low. This helped, but still either too much or not enough. I set the crossover to 100Hz (should I just turn this off since the Logic7 amp has a built in low pass?) Bass EQ = Off. Also, one last thing. I've set the 100Hz EQ Setting on the iDrive to about 2 or 3 notches from the bottom. Does moving that level effect the sub? And last thing, in my e39 I unplugged the Nokia woofers in the rear deck which are similar to the woofers under the e60 seat. Again any thoughts on that?

I know this is a hodge podge of thoughts, but any input helps.

 

the L7 sub output is already crossed over, but it's on the upper end of what I would consider a sub cutover. you'll still need to cross it over, but i'd use a much higher frequency than usual (since there's already at least a 6db/oct slope going on there, if not 12db.)Mine's somewhere north of 200Hz right now- it's hard to tell because the markings on the adjustment screw are so far apart.

if the alpine has a bass eq setting, turn that off. Mine did on channels 3+4 and it was ridiculous. the sub sounds great with it off but ridiculously overpowers the L7 with the switch on.

I'm running an old school kicker 10" competition in a boston acoustics sealed box with a passive radiator (don't ask, it's a frankenstein of parts I had lying around to do this as a proof of concept before I spent major cash on the sub and amp) and it sounds great. So much that while I might look for a smaller digital dedicated sub amp (alpine pdx-1.600, i'm looking right at you) to make the fit inside the trunk panel better, I think i'm just going to keep the sub.

 

what gain control knob are you using? I thought alpine didnt make one.

 

Not very familiar with the BMW Logic 7 system but I always thought the Alpine amp has a built in cross over...anyway set it down to 70Hz; if possible, get some frequency filters and connect to the output line between the amp to the sub to ensure that the frequency doesn't get any higher. Also, I think you need to turn the gain as low as possible for it to compensate with the sound level from the stock amp. I think the bass is drowning out your mids and highs. I personally do not think BMW's speakers are good quality anyway especially when they're old like the ones in my car.

GL