Homemade bassblockers

[haydenm315]

Even though alpine included sub control on my 7863 head unit, their low pass and high pass controls filter all channels. It would seem wise to only filter the front/rear and leave the sub for control by the amp, but apparantly they want you to buy better models or equalizers or something. I've decided to take the cheap way out and install bass blockers. Quick research on the net shows that these things are simply a nonpolar/bipolar capacitor to filter out certain frequencies.

The site I went to says.... To figure out what frequency you want to cross em over at, here's a quick equation:

C = 1 / (2 * pie * frequency * speaker resistance)

I really have no clue what frequency I want to cross them over at, but I definately want to reduce the amount of bass getting through to them. I don't know much about stereo stuff, but am learning. I found both 4.7 and 10 microfarad nonpolar electrolytic capacitors at radio shack. What I don't understand is they both say For speaker crossover 4khz at 8ohms. How can they both crossover the same frequency if they're different? My front speakers have a resistance of 4ohms. Does this mean the capacitor frequency is going to be cut in half because twice as much gets through? Pardon my ignorance to electronics. It was taught to me briefly in hs during physics but I never took a college course. I do have all the records and equipment downstairs from my dad's course for reference

 

[SHOZ123]

4 ohms will be half the 8 ohm frequency. I would choose a frequency somewhere around 150-200 Hz.

 

[shoRunner]

4khz is way to high to crossover at unless its tweeters. i had my crossover set at 120hz for my front speakers and 80hz for my back speakers. you can buy bass blockers from many stores (circuit city) that you insert in your RCAs and they block at a certain frequency. they're only like $5.

 

[haydenm315]

shoRunner:
4khz is way to high to crossover at unless its tweeters. i had my crossover set at 120hz for my front speakers and 80hz for my back speakers. you can buy bass blockers from many stores (circuit city) that you insert in your RCAs and they block at a certain frequency. they're only like $5.

Well then it's crossed over at 2khz. I think the system sounds much better now that I dont' have to filter everything to help out the front speakers. I could adjust the balance but then the car is sound heavy in the rear. Now if I can just get the seat belt holder mounted on the deck to stop rattling

 

[92sho16]

Any non polarized 115-133 mircrofarad capictors are what are generally used for bass "blockers". The 133 microfarad caps at 4ohms will cut off at 300hz.

 

[SHOZ123]

What value cap will cut off the bass at 200hz @4 ohms?

 

[ScotSHO]

200 microfarad