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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
mijostyn's avatar
mijostyn
8,570 posts
 
It sounds like a 12 dB/oct Linkwitz-Riley crossover.
erik_squires
16,416 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
dannybad OP
20 posts
 
erik_squires- I believe that you are correct.  It does look like a Zobel.  I will do some more reading to understand this, but at first glance it makes sense.  Thank you and everybody else for your comments.  
timlub
2,042 posts
 
It is certainly doing impedance correction,  but 6 mfd sounds very low.  Years ago,  I rebuilt a pair of these and ran actual curves... I'm sorry, I just don't remember, but It seems to me that it was more like 20 to 40 mfd to correct the impedance bump in these. 5 ohm does sound right on the resister. 
audiokinesis
2,753 posts
 
Sometimes what works is a second-order lowpass filter with a lower-than-normal L/C ratio and a resistor in series with the capacitor on the shunt leg. This is a damping resistor which prevents response peaking and its accompanying impedance dip. This would be called a "damped second order lowpass filter", and it can look a lot like a first order + Zobel.

Duke
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