Calculate xover freq from component values?
- Thread starter Zombie
- Start date
awkwardbydesign
Officially Awesome
Xsim?
A 2nd-order Butterworth LP filter consists of:
* a 1.8mH inductor in series with the driver
* plus a 14uF cap across the driver.
A 3rd-order Butterworth HP filter consists of:
* a 13.3uF cap in series with the driver
* followed by a 2nd cap - 40uF - also in series
* and a 0.95mH inductor connected across the driver between the 2 caps.
These values are for:
* an 8 ohm driver
* and 1000Hz 'roll off' frequ.
If you double the frequ ... you halve the coil & cap values.
If you halve the frequ ... you double the values.
If you change the XO 'roll off' frequ from 1000Hz to 500Hz ... you halve the inductance & double the capacitance.
If you know your XO values, the above should enable you to work out where the LP & HP 'roll-off frequencies are.
If you want to send me the LP & HP filter component values, I will sim them for you (I use lspCAD) and show you:
1. a graph of the result, plus (potentially)
2. a slightly different combination of LP & HP filters which should result in a flatter overall FR.
Just send me a PM.
Zombie
pfm Member
I can change it if I have an impedance file.Then it's not much use.(I presume it's free software?)
awkwardbydesign
Officially Awesome
But you can add parallel or series resistance to it to effectively change it.
Zombie
pfm Member
it goes bonkers when I add a 24 Ohm resistor in parallel on each speaker
awkwardbydesign
Officially Awesome
Oh, sorry to hear that, it has worked for me.
Zombie
pfm Member
I have probably done smth wrong
PigletsDad
My intelligence test came back negative.
Regardless of the orders, you would hope the HP and LP corner frequencies match! So why not just use one of the online calcs for say the LP section by itself?
No - if the order of the slopes don't match ... you need to stagger the HP & LP 'corner frequencies' for the flattest overall FR.
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