MG-Rover.org Forums banner
1 - 13 of 13 Posts

·
Registered
other_manufacturer
Joined
·
2,464 Posts
Discussion Starter · #1 ·
Years ago, and I mean years, it was common practice for people to put capacitors on the back of their speakers (mids and tweeters) to block low frequencies.

Being the cheap skate that I am, can I still buy small capacitors to solder on the back of the standard-fit door speakers in my 75 ?

If so, anyone tell me what (rating) I need to look for in my local Maplin ?

Cheers :beer2:
 

·
Registered
Joined
·
37 Posts
Capacitors

not sure on car speakers, if you can let me know what wattage you are putting into them (I assume they are 4 Ohm) I can find out!, but if you do that you won't be getting full range out of them, or have you got a cunning plan?!
 

·
Registered
mg_zt
Joined
·
140 Posts
RichK said:
If so, anyone tell me what (rating) I need to look for in my local Maplin ?
Cheers :beer2:
Really they need to be non-polarised electrolytic capacitors. The value depends on the application - midrange, tweeter etc. At maplin JA75S (10uf, 100v) is quite suitable. Buy 4 (they are only 6p+VAT each) and try them in series and parallel and see what sounds best. If you want more lower frequencies use JA72P or VM76H. I have no connection with Maplins BTW
 

·
Registered
other_manufacturer
Joined
·
2,464 Posts
Discussion Starter · #4 ·
Sorry Paul just double checking, I need to loose the low freqs and keep mid/treble running. That Maplin part number still what I need ? (thanks for that btw!)

DJ Sense - 25wrms - By not getting full range do you mean I'll loose some mid/treb on the speakers by doing this too ?
 

·
Registered
Joined
·
2,075 Posts
I don't see how the power you're feeding the speaker matters?

No one has mentioned that the value of cap you use will determine the crossover point, and that you need to have a crossover point in mind. If they're OEM speakers, and you have something for the low frequencies already in place, I'd recommend that you start with a crossover point of 80Hz.

An 80Hz crossover point for an 4 ohm driver, would require a cap of 497 microfarads. Anywhere pretty close to there should be fine.

For more info, try this page: http://www.bcae1.com/passxovr.htm

HTH

Mark
 

·
Registered
mg_zt
Joined
·
140 Posts
The power affects the voltage rating and the current rating of the capacitor.
According to my calculations 100v capacitors are good for 300W or more into 4 ohms. The current rating of the capacitors would not be however!
 

·
Registered
other_manufacturer
Joined
·
2,464 Posts
Discussion Starter · #7 ·
Top notch info there gents, thanks very much !

The door speakers are indeed oem and there is an amp/sub in the boot. If I turn the head unit up over about quarter of the way, I can hear the door speakers breaking sweat, push it much more and I'll have to replace them (which I don't want to do yet) :)

Mark, the only bit of what you said that I didn't understand was the microfard part. Is that measured in "uF" ?

Maplin offer a 47uF 100V non-polarised electrolytic capacitor, do I need ten times that value or is that about right ?

Thanks again !
 

·
Registered
mg_zt
Joined
·
140 Posts
RichK said:
Just double checking before ordering.
No typo. 470uf to block the lowest frequencies. 47uf for a mid range.

440uf about 90Hz (2x JA71N)
220uf about 180Hz (1x JA71N or 2x VM 76H (cheaper & better*))
100uF about 400Hz (1x VM76H or 2x JA72P (better*))
47uF about 800Hz (1x JA72P)

for approx 4 ohm speakers.

phew. That why I always buy a few to try out and see what sounds best.

* both capacitors in parallel = higher current capability and less internal resistance.
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top