Do you have distorted bass in the front woofers of your HIFI? I have the fix!
I swapped out the stock fronts with MB Quart a while back and it was like night and day the amount of low end I gained with them but when I would crank up a deep bass song they would not be able to take the excursion. So I wanted to tone them down a little but maintain a good solid front end to keep up with my sub install. I searched for a good cheap 6db crossover (passive) at about 70hz or so. I found that the right frequency (6db rolloff at around 65hz could be accomplished with a pair of parallel 330uF caps on each positive speaker terminal. The sound is much improved and if you have the same problem this is an easy fix. Below is the link from Partsexpress.com. Hope it helps someone! You need 4 off them, 2 per woofer.

http://www.parts-express.com/pe/show...TOKEN=37851880

 

My problem is that there is too much bass going to the center 4" speaker in the door causing it to distort. Will these work on that speaker? I have a 2008 Clubman S with the Hi-Fi

 

I would reccomend a little higher frequency for the 4". Something above 100hz for them will take most of the bass out. If you want I can do a calculation and post the correct cap and frequency? Let me know.

 

For around 200hz (leave below this frequency to the woofer) you will need one of these per speaker.
http://www.parts-express.com/pe/show...number=027-366

 

http://www.apicsllc.com/apics/Misc/filter2.html

 

Putting a capacitor in parallel with the middle speaker will eliminate low frequencies from the woofer also, if they are all fed from the same amplifier output (I don't know if MINI feeds each door speaker separately, but I doubt it)

 

caps go in series(not parallel)....remove the middle speaker grill and the speaker and cut the + wire and wire a cap in line with the + wire....at that point it should have no effect on the lower speaker.

Adding coils in parallel(across the + and - wires) with the cap in series changes the slope to 12db.

If i was going to attempt this mod i would replace the mid door speaker with a true tweeter and build a simple 2-way crossover that i would house in the armrest. That would be the cheapest and easiest way to improve the sound of the mini, wand would not require removing the door panel...just the midrange cup.

 

Minisq, great link above!

As stated above the filtration at that specific speaker with a cap in series will not effect the other speakers.

 

What is the upper frequency going to the 6" lower door speaker? Wouldn't you want the middle door speaker 4" to take over where the lower speaker stops.

 

not sure where the upper frequencies are set but Yes, having the 4" take over just under where the 6.5 cuts would be optimal.

 

I got a couple of 100uF capacitors at Radio Shack ($3) and installed one in the 4" speaker in the passenger door last night. Afterwards I tested it by setting the fader all the way to the front and varying the balance between the left and right sides. Boy what a difference, now
that mid speaker doesn't get muddy when you add a little volume to it. I then installed one to the drivers door speaker. Installation was very easy, using 2 screw drivers pry off the mid speaker enclosure from the door panel (this is separate from the door panel so you don't have to remove any of the panel). On the drivers side you have the switch for the mirror, but you don't have to remove it, just slide the housing away from the speaker and let it hang on the wires to the switch. Remove the 3 torx screws for the speaker and unplug the speaker. Cut away couple of inches of insulation tape from the speaker wires. Cut only the + wire about 1 inch from the connector and soder in the capacitor. Use shrink wrap or tape to cover the exposed ends of the capacitor. Plug the speaker back into the connector and install the speaker and snap the housing back onto the door. I think it has to be the best benefit/$ you can spend whle keeping the stock speakers. I can now run the fader to the center setting and have the bass set to 2 or 3 with no distortion.
Below is a picture of the passenger door with the capacitor in place. There isn't a lot of extra wire, so don't shorten the wire while adding the capacitor.

Oh, my mid-door speakers didn't have any manufacturers (Harmon or Alpine) name on them, only the
BMW emblem, part number and "Made in Hungary" was on it.

 

This is a very interesting thread. Im about to add a 100uf capacitor to the 4" speakers.
Does anyone know if this same principle can be used for the tweeters? I find them to be too loud or harsh. I was thinking on replacing them but someone used Infinity Kappas and he said they were very harsh too. Im beginning to think that it has more to do with the amp signal rather than the quality of the stock hi fi tweeters. I have tried to solve the problem adjusting the treble but it doesnt help. If I could only lower the volume a bit.

 

THere is already a capacitor in the line for the tweeters to eliminate the base from them but adding anohter cap will not reduce their volume. You would need to add a resistor to do that but you would need a very small value resistor.

 

Thanks for your quick answer Schatzy. Do you have any idea of what size resistor could help? I was also thinking of placing something between the grill and the tweeter to "dampen" the sound a little.

 

Can someone tell me (us) how to determine polarity of the speaker wires? One of mine has a black stripe and the other an orange or brown stripe. Does it really matter with a non-polar cap? Also, the capacitors sourced from Parts Express are much larger than those shown above by Big Jim Slade. They must be wired in using an additional wire lead so that they are not trapped behind the speaker basket. TIA

 

On the 2008 Clubman S the passenger side + should be blue with a black stripe (- is blue with a brown stripe) and the drivers side + is blue with a white stripe (- is blue with a brown stripe). If you have both speakers out the negative wires should have the same colors on them.

 

Here are the speaker wire colors at the X9331 connector of a 2007 R56. I don't think they have changed much.

 

Hi David,

I want to purchase a 100uF capacitor for my 4" speakers on a hi fi system. Big Jim Swade is not online to ask him what voltage capacitor he installed. Do you know if 100V is what I need?
Thanks for this great thread.

 

I don't remimber the voltage, I got them at Radio Shack for $1.49 each. I think they were low voltage though, maybe 18v?

 

100V is the spec for the filter caps. I just installed 200uf caps on my 4" speakers to push the rolloff a little higher. At very high volume the system still sounds like crap, but at any normal listening volume it really cleans up the midrange. Remember, the cap must be non-polar......couldn't find any at Radio Shack.

 

I couldnt find them at RadioShack either. There are so many voltage options. Dont know which one to pick. And should I place a 100 or 200uF?

 

See post #4 above. 200uf caps will roll off slowly below 200 Hertz which seems to work well for de-mudding the 4" midrange. This link has a chart for choosing other roll off points.
http://www.carstereo.com/help/Articles.cfm?id=1