weird rating on a capacitor

Discussion in 'Home Theater Projects' started by David Giesbrecht, Aug 7, 2003.

  1. David Giesbrecht

    David Giesbrecht Second Unit

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    A couple of weeks back I embarked on a mission to slightly
    improve the poor sound quality of my pyramid speakers witch are currently in my HT setup. I decided I needed a better crossover in it than none at all, except for the single bi-polar cap that came atatched to the tweeter. The problem is that the cap does not have a uF rating on it all it says is 3.3 MFD. So being the impatient person I am I decided I would just follow the basic chart in the parts express catalog and it should work better than what I had. So I ordered up 5 20 uF Solen caps and 5 .33 mh air core inductors to get an x over point of 2 khz for 4 ohms. After installing the parts in all my speakers and putting them back together it was time for first listen. So I grabbed my dads Styx Equinox CD and WOW! what a difference The mids no longer sounded so strained and grainy and the treble was much faster sounding and cleaner. The only thing that concerns me is that I can now feel the domes on my tweeters vibrate and I'm afraid I'll blow them. I think they got crossed over to low. So I'm now wondering what the rating was on the old caps.

    If anyone has any ideas please help!
     
  2. ThomasW

    ThomasW Cinematographer

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  3. David Giesbrecht

    David Giesbrecht Second Unit

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    Is it possible that I might also have the cap hooked up backwards does it matter on Solen caps?

    20 UF and 3.3 uf is quite a diiference i think I better put the old ones back on but wouldn't 3.3 uf put the crossover frequency somewhere around 10 khz on a 4 ohm driver that seems way to high for a 1" dome don't you think?
     
  4. Chuck Bogie

    Chuck Bogie Second Unit

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    Sounds like the tweeters may have been crossed VERY high in order to protect 'em.
     
  5. ThomasW

    ThomasW Cinematographer

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    Solen caps aren't polarized so it doesn't make any difference which direction they are wired.

    One shouldn't use 'generic' XO charts for their speakers. Proper XO's are designed after measuring the performance of the drivers in the box, and having access to all the T/S parameters. This info is then put into a XO design program.

    Regarding XO mods unless one knows what their doing it's better to leave well enough alone than to blindly shoot in the dark. XO's can't be correctly tuned by ear.......

    I suggest returning the components and saving your money to buy a speaker kit when you have enough cash. That way you'll have a proven performer and very low risk. It's either that or start buying test equipment/software and learning speaker design theory.
     

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