polar caps for bass blockers

[donnysparks]

Sorry, fairly off topic.  But you guys are the most shmartest people I know and I knew you'd have the answer.  I am trying to round out the sound in my old mercedes with 4" speakers all around.  I just hid a small woofer under the seat so I'd like to block freq's below 100-200hz from the 4" ones.  NOBODY local has nonpolar caps in the range I need.  I thought I heard somewhere you could use polar caps in series for this.  Is that true?  If so, how is it done? Pos to pos? neg to neg?  Caps in series have a subtractive effect, right (800mf-----800mf=400mf)?  Thanks in advance and sorry to stray from the cool stuff.

ray

 

[donnysparks]

So if...

1      1      1      1 
-- =    -- +      --      +    --    + ···
CT         C1         C2       C3

...when they are connected with the leads like this:  --(-)---(+)---(-)---(+)---
does the same hold true if you connect the pos to pos or neg to neg?  Do I need to just shell out the big : bucks for premade ones?  Seems to go against our principles.

 

[abbey road d enfer]

You can connect them pos to pos or neg to neg, doesn't make a difference.

 

[donnysparks]

Thanks very much!  Makes sense you could do it either way.  You think the relationship above still applies in that arrangement?

 

[CJ]

you might need to deaden some panels if you start dropping dome lights and hardware with the sub,

you buy this stick on stuff, very expensive, but 1 sq foot will silence a door, 2 sq ft a 1/4 panel, hera me?

 

[donnysparks]

hera me?

Whaat? Speak up sonny... ;D

No boom going on here.  Just dialing in enough to pick up the slack for those 4" speaks.  Sub is under my driver's seat.  Just have to remember to notch out the brown note.

 

[mikep]

Well, if there is any dc offset coming out of the amp, then it might matter, and could be either polarity, use a meter to check with the speaker disconnected. but if it was enough dc to matter to a cap, then your speqkers would already be smoked anyways.  What kind of old mercedes? still have the stock radio? I drive an 84 300sd. Stock speakers still working, replaced the becker radio last year.
Mike p

 

[donnysparks]

Well, if there is any dc offset coming out of the amp, then it might matter, and could be either polarity, use a meter to check with the speaker disconnected. but if it was enough dc to matter to a cap, then your speqkers would already be smoked anyways.  What kind of old mercedes? still have the stock radio? I drive an 84 300sd. Stock speakers still working, replaced the becker radio last year.
Mike p

Thanks very much for the info.  Its an '82 300TD (wagon).  I tried and tried to keep the stock radio, but it would spit tapes out at the slightest vibration and would stop playing if you wedged the tape in.  I can't handle only listening to the radio.  I saced it and kept all the original car wiring intact by running my own wires.  Mine had the stock speakers, and they sounded good, but I found a nos pair of 4" KEF hi fi speakers with the tweets built into the dustcap and they sound incredible in the dash.  Have you seen the new Becker models?  A bit pricey, but wouldn't that be cool?  Small world--I've been trying lately to get my wife in an SD or SDL.