How to build a 60 Hz filter?

alesnoop

I have a subwoofer in a car. The box seems not to be enough large so when bass with frequencies below 60Hz (I tested with a professional frequency generator) is played, the subwoofer distorts badly through its hole...

I am considering the adding of a filter that will "trim" frequencies below 60 hz. I believe that the filter diagram should include some capacitor and inductor but although I have surfed a lot I have not found any guidance on the specs of the diagram...

Any suggestions? (Pls notice that I may not change anything on the box...)

RuSsMaN

Couple of things - first, you might want to post this in the 'car audio' section of the forum

Second, more information on your driver(s) is needed. Impedance being the key.

Are you sure you want to trim BELOW 60Hz, not above?

Here is a basic crossover link for you, has both high and low pass sections. This should give you the info that you are looking for, but It sounds to me like you have a improperly matched box/driver/port. Dropping in a simple high or low pass may work as a bandaid at best.

http://www.partsexpress.com/resources/xover.html

Cheers,
Russ

alesnoop

Russ,

You are actually right, the whole stuff is not going to work sufficiently well but I have no choice. The sub is a BOSE predefined and built for Porsche 986 so there is no way of playing with dimensions and so on - there is no room at all....

The impedence of the sub is as follows:
2 speakers 4 ohms each in parallel, ie 2 ohms as a whole

Thnx for the link but it seems broken...

alesnoop

Russ, I forgot to mention that YES I need to trim BELOW 60 Hz... The distortion happens actually below 55 Hz and I tested with a professional machine...

Rgds,
Alexis

RuSsMaN

Link seems fine on my end...good luck with your endeavor!

RuSsMaN

I copied the info into a word doc for ya...

alesnoop

Thanks for the attachment, I finally opened the web page thru another internet provider (!?!)

The info is very helpful but although I am an engineer I do not understand the schematics (apart from the inductor, capacitor that I understand them)...

Thanx for your help,
Alexis

burdette

Are you using the Bose electronics (the original amp) that was with the sub? If not, that may be your problem.

My Maxima originally came with a Bose sound system. The speakers alone sounded like **** without the Bose amps because they were tweaked to control/augment response.. i.e. boosting certain frequencies, etc. Replacement units were outrageous, which is why I've replaced the entire system all around.

The amps are also tweaked for individual car models. Even if you're using the Bose amp, then part of the problem may be that you are using it in a different car.

alesnoop

it is original Bose system, it was on the car from the factory...

i simply believe that they tried much but at the end they did not give a final touch. the result is that the sub is actually farting, ashame for Bose...