BMW 3-Series (E90 E92) Forum - View Single Post - Top 3 DIY "bang for your buck" Logic7 System Upgrades

kaigoss69 · 08-16-2010, 07:40 PM

IMO, and based on my experience:

#1: Add a tweeter to the center channel.

This does wonders for improving the imaging of the L7 system. Before, voices were located close to the left tweeter pod, and after they are very close to dead center, almost head-high. This also adds some "crispness" to the front stage. Highly recommended.

Cost: $0 - $90
Installation time: 1-2 hours
Difficulty: 2 (1-9)
Pics:

L7 tweeter with in-line crossover and plug-in connector

Tweeter plugs right into midrange

Tweeter mounted using high-tech bracket made from tin cookie box

Gorilla glue is awesome

Make sure the tweeter is mounted such that the surface does not touch the grille.

Note: If you want, you can "borrow" the tweeter from the rear deck (only in a sedan). Unless you like to fade to the rear of the car, you will likely not notice the difference with or without the tweeter back there.

#2: Amplifying the underseat woofers.

Basically, the OEM amp does not put out enough power for these to play to their full potential. Yes, they are OEM drivers and have their limitations, but they happen to be well-built, are optimized for the enclosures they're in, and do sound quite good with added "responsible" power. Notice to bass-heads: this upgrade is not for you!!! This will not shake the hell out of the car, make your system be heard for 5 blocks, or even make your rear-view mirror shake - it just allows the OEM "woofers" to keep up with the rest of the system.

Cost: $100 - $300
Installation time: 1-3 hours
Difficulty: 3 (1-9)

I originally did this the simplest way possible: Cut the OEM speaker wires coming from the OEM amp in the trunk, and feed the signal into an amp with speaker-level inputs and auto turn-on circuitry (like Blaupunkt Tha1250PnP). Then connect the speaker output from the amp back into the OEM wiring going to the woofers. You can use a mono amp, like I did, or stereo, the difference is virtually inaudible. Use the high-pass filter on the amp to protect the OEM woofers from overexcursion (and melting of the voice-coils), and set it at about 50 to 60 Hz. You can set it lower, or "off", but be very careful!

If you don't want to cut the OEM wiring, and/or you want to use an amp without speaker level inputs and auto-turn-on circuitry, forum member Technic has a harness for sale that will allow you to hook up an aftermarket amp without cutting any wires, period. It doesn't get any easier!

This thread was very helpful for me when I did this upgrade: http://www.e90post.com/forums/showth...ght=logic7+amp

#3: Install MS-8 Processor to replace L7 amp
(requires #1 upgrade above)

Info here: http://www.e90post.com/forums/showth...highlight=ms-8

Cost: $700 - $1000 (using OEM speakers)
Installation time: 3-5 hours
Difficulty: 4 (1-9)

P.S. don't try to remind me about the SWS-8 upgrade, it is #4 and didn't make the list!

08-16-2010, 07:40 PM	#1
kaigoss69 Brigadier General 300 Rep 3,969 Posts Drives: '08 335i Join Date: Jul 2008 Location: JAX iTrader: (6)	IMO, and based on my experience: #1: Add a tweeter to the center channel. This does wonders for improving the imaging of the L7 system. Before, voices were located close to the left tweeter pod, and after they are very close to dead center, almost head-high. This also adds some "crispness" to the front stage. Highly recommended. Cost: $0 - $90 Installation time: 1-2 hours Difficulty: 2 (1-9) Pics: L7 tweeter with in-line crossover and plug-in connector Tweeter plugs right into midrange Tweeter mounted using high-tech bracket made from tin cookie box Gorilla glue is awesome Make sure the tweeter is mounted such that the surface does not touch the grille. Note: If you want, you can "borrow" the tweeter from the rear deck (only in a sedan). Unless you like to fade to the rear of the car, you will likely not notice the difference with or without the tweeter back there. #2: Amplifying the underseat woofers. Basically, the OEM amp does not put out enough power for these to play to their full potential. Yes, they are OEM drivers and have their limitations, but they happen to be well-built, are optimized for the enclosures they're in, and do sound quite good with added "responsible" power. Notice to bass-heads: this upgrade is not for you!!! This will not shake the hell out of the car, make your system be heard for 5 blocks, or even make your rear-view mirror shake - it just allows the OEM "woofers" to keep up with the rest of the system. Cost: $100 - $300 Installation time: 1-3 hours Difficulty: 3 (1-9) I originally did this the simplest way possible: Cut the OEM speaker wires coming from the OEM amp in the trunk, and feed the signal into an amp with speaker-level inputs and auto turn-on circuitry (like Blaupunkt Tha1250PnP). Then connect the speaker output from the amp back into the OEM wiring going to the woofers. You can use a mono amp, like I did, or stereo, the difference is virtually inaudible. Use the high-pass filter on the amp to protect the OEM woofers from overexcursion (and melting of the voice-coils), and set it at about 50 to 60 Hz. You can set it lower, or "off", but be very careful! If you don't want to cut the OEM wiring, and/or you want to use an amp without speaker level inputs and auto-turn-on circuitry, forum member Technic has a harness for sale that will allow you to hook up an aftermarket amp without cutting any wires, period. It doesn't get any easier! This thread was very helpful for me when I did this upgrade: http://www.e90post.com/forums/showth...ght=logic7+amp #3: Install MS-8 Processor to replace L7 amp (requires #1 upgrade above) Info here: http://www.e90post.com/forums/showth...highlight=ms-8 Cost: $700 - $1000 (using OEM speakers) Installation time: 3-5 hours Difficulty: 4 (1-9) P.S. don't try to remind me about the SWS-8 upgrade, it is #4 and didn't make the list! Last edited by kaigoss69; 08-21-2010 at 12:33 PM..
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