Crossover Capacitor

[philh]

As I've said in other threads, I'm just a mechanical engineer, so go easy on me

I'm also really really cheap! LOL

Noticed one day my 30 yo Criterion 2005 speakers (with replaced woofers) just didn't sound like I wanted them to. So, just for fun I started fooling around with braided CAT5 (extra from house wiring project), and was shocked at the improvement. BUT, in the process had to replace the binding post, and managed to crack a capacitor. Since the wife got the new puppy, she said I could buy new speakers and settled on Beta 50's. Before I spent the $1,000 (which BTW freaked her out) going to take one more stab at the speakers. Put in replacement 15mF film(?) capacitors and suddenly my 2-way speakers have wonderful sound, including the missing midrange.

Now for the question, what does the capacitor do, and why did I hear the improvement in the mid range? Also, why didn't the cracked capacitor sound any different from the non cracked one?

 

[guess88]

how'd you break a binding post and crack a capacitor by changing speaker wire to cat 5?

 

[Rip Van Woofer]

Phil, I'd guess that the original electrolytic (my guess) caps in your old Criterion speakers had simply reached the end of their life, so of course replacing them helped! Main advantages to film caps are long life, stability, and lower noise than many other types. Oh, and I think you can get them in tighter tolerances than most electros, too, which is a good thing. But there's no magic involved beyond that.

 

[Francious70]

For info on why the cap does and why it helped, read this.

http://www.bcae1.com/passxovr.htm

What you did was fix a passive crossover that had no low-pass filter.

Paul

 

[philh]

how'd you break a binding post and crack a capacitor by changing speaker wire to cat 5?

Good question Typical mechanical engineering solution to a problem!

The "binding post" that came on the speaker was limited to {guess} 14g. The CAT5 cable I assembled was bigger the spring loaded opening. So, I ordered a nice new generic 5 way binding post to install. BUT, the old binding post was covered in the soft epoxy that held the Cap in place. Using my big hammer solution, attempted to pry the Cap and epoxy out of the way. Didn't work so hot Then just to make my day, when I put the new binding post in, once again, decided the small screw could take every bit of force I could apply to the wrench. Guess what, it didn't!

Probably sorry you asked

 

[philh]

For info on why the cap does and why it helped, read this.

http://www.bcae1.com/passxovr.htm

What you did was fix a passive crossover that had no low-pass filter.

Paul

Thank you, that was easy for even me to understand

But, I wish I had diagrammed my xovr, not sure I understand what it's attempting to do. From memory, there's an inductor in parallel to the capacitor leading to the tweeter, and one in series to the woofer, but this is from the memory of someone that thinks you can use screwdrivers to pry capacitors