Hello and a good day to all, I am fairly new to crossover designs, I am trying to make a passive 3rd order butterworth crossovernfor my subwoofer, I have the following components:
L1 2.85mH ESR 0.15ohm ferrite bell core
C1 3 x 220uf bipolar caps for the shunt
L2 1.18mH ESR 0.2ohm same ferrite bell core inductor
The woofer has a Re of about 3.8ohms
I am trying to get close to about 150hz cutoff,
I did some calculations and I should be close to this value with the given components, but I am new to crossovers and maybe my calculations are wrong
Could anybody help me if these values will result in close to 150hz?
I can alter the capacitor to increase the value if needed, but I don't have larger value inductor
Thank you all for your time and help with this
Criss
L1 2.85mH ESR 0.15ohm ferrite bell core
C1 3 x 220uf bipolar caps for the shunt
L2 1.18mH ESR 0.2ohm same ferrite bell core inductor
The woofer has a Re of about 3.8ohms
I am trying to get close to about 150hz cutoff,
I did some calculations and I should be close to this value with the given components, but I am new to crossovers and maybe my calculations are wrong
Could anybody help me if these values will result in close to 150hz?
I can alter the capacitor to increase the value if needed, but I don't have larger value inductor
Thank you all for your time and help with this
Criss
You need to consider the real (usually very varying around resonance frequency) impedance of the driver in the enclosure. Eventually you need to equalize the (upper) impedance peak.
I suggest you measure or simulate the impedance curve and then simulate and tweak the filter.
Thank you for your response, unfortunately I cannot messure the t/s parameters of the woofer, these are a pair of Definitive Technologies BP-7004 speakers, they had active amplifiers for the woofer part, but they are defective (quite common) I am currently using an off the self 2nd order 150hz filter with acceptable results, but I would lIke to build a 3rd order filter (the type that was used for these speakers) I can tweak later for humps and bumps, but I am trying to figure out if these inductor/cap values should give close to 150hz, so I can have a start at building and after that tweaking for better flat response
Thank you again
Criss
Thank you again
Criss
You seem to sum it up well enough. You’ll only get approximately close, so having the ability to EQ is good. That will get you there.
Thank you, I tried using chatgpt (new to this) to check my calculations but every time it gave on flicking results and nothing close to 150hz, results varied from 240hz to 1220hz 😐, online calculators also suggested 6.2mh 370uf and 2.2mh for about 150hz, but a math friend did some calculations and said given these components I have I should be close to 150hz not accounting for impedance peaks around fs, and given a constant re of about 3.8ohms, but I know there are people with much more experience here in designing crossovers and I wanted to double check if possible, always better to have more opinions,
Thank you again all for your time and help
Thank you again all for your time and help