LX-mini Crossover Article

Playing with Nelson Pass MicroCap-simulation

This sunday morning I was playing with MicroCap and LTSpice Nelson Pass is offering to us. Thanks! Big fun!

I want to get a bandpass between 80 Hz and 2500 Hz (for the mid-bass). Playing around to make the lower crossover point switchable (50 Hz /65 Hz/ 80 Hz / 100 Hz) by changing/ switch C1.
The highpass from 2000 - 2500 Hz up for the tweeter. I forgot to make screenshots. My present values are:
Highpass:
C4 4nF
C3 4nF
R1/ R2 18kOhm
R12 0K
C15 0nF
R9/R10 100 Ohm
C16 3nF
R11 1kOhm

Low / Bandpass:
C1 switchable 100nF = 52 Hz (-3dB)
60 nF = 65 Hz

47 nF = 80 Hz
33 nF = 100 Hz
C2 100nF
R6 47 kOhm
R7 15 kOhm
R3/R4 10 kOhm
C13 15 nF
C14 10 nF

Till now - only simulated! Need some new caps....Sorry for the bad pics.
 

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The crossover points i need are configured but ; they can easily go changed ; maybe a way to modify those crossover points by using a potentiometer or fixed resistors would be great. I also found that in simulation AC->Slider can create a pot out of any resistor allowing a almost realtime curve update.

see the archive here

Edit:
and screen shot; see sliders on right side :) :

wiki_asset.php
 
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First order xover changes question

I would like to try a first order xovr setup and would like to know how to do that. I know the high and low sections have 2 pole filters for a 2nd. order implementation, but I am not sure which capacitors or resistors to bypass in each section to accomplish a 6 db/octave filter for both high and low pass sections.

And also, a comment or maybe a question I Have been experimenting with the phase connection to my subwoofers. I started with inverted woofer connections but last night I changed the connection to "normal" and it seems to me the that the blend is much better ?.. So now, supposedly the woofers are out of phase. Both the mains and sw's are open baffle - Spatial M4's and a diy Ripoles. Thanks!
 
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