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Crossover Capacitor In Parallel with Woofer

I successfully recapped my Altec Lansing Bolero 890C speakers and they sound amazing.  This has helped me understand how crossovers work but there is a section in it that is still strange to me.  It looks like there is a 6uf cap and a 5 ohm resistor in parallel with the woofer.  Is this making it a 2nd order (12db) crossover point?  Can anyone explain exactly how that cap is working on the low end or is it just effecting the slope of the the frequencies being crossed over? Thank you in advance.

dannybad
erik_squires
16,049 posts
 
Sounds like a Zobel:

https://speakermakersjourney.blogspot.com/2016/12/crossover-basics-zobel_8.html

The quick answer is it helps the woofer impedance stay flat so the low pass filter works more consistently.
erik_squires
16,049 posts
 
Oh, so the key difference when looking at a crossover between a 2nd order and Zobel tends to be the size of the resistor, and cap.


The resistors in a Zobel are in the 4-8 Ohm range. The resistors in even numbered poles is tiny, anywhere from 0.2 to 1 Ohm.

Also, the cap is smaller, since it's working up higher in frequency.


I strongly recommend you try finding XSim and downloading it. It's free, and will help you simulate and see how different crossovers work.
elzorrooro
1 posts
 
I use ngspcie-30, downlaoded from SourceForge - a free program.
https://sourceforge.net/projects/ngspice/files/ng-spice-rework/30/

Lots of info on passive and active circuits.

I also use a free graphics interface called kjwaves_1.1.3
http://ngspice.sourceforge.net/kjwaves.html

mijostyn's avatar
mijostyn
8,570 posts
 
It sounds like a 12 dB/oct Linkwitz-Riley crossover.
erik_squires
16,049 posts
 
Yep, those are good simulators, but they may not have a good model for a speaker.

The link I provided actually has simulation files with actual speaker drivers. :)

Best,
E
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