According to the resonance formula; Fc = 1/(2 x pi x sqrt(LC)), it’s clear that Fc depends on the product of L and C. So there are many combinations that yield the same product values. For example, 3.5mH and 100uF gives Fc of 270Hz, so does 4.0mH and 87uF combo.
However, assume Re of the driver is 4 Ohms in both combos, the difference is on Q of the filter. Consequently,
1) What is the criteria for choosing L, or C, for the initial step? That is, assume Re = (ideal) 4.0 Ohms, L = 3.5mH or 4.0mH for the first component.
2) With Re = 4.0 Ohms, the 3.5mH and 100uF produces Q = 0.676, while 4.0mH and 87uF produces Q = 0.590. Which one is more preferred?
I know the process should involve measurement, however, I also believe the calculation could be performed before measurement (for some people) as well.
However, assume Re of the driver is 4 Ohms in both combos, the difference is on Q of the filter. Consequently,
1) What is the criteria for choosing L, or C, for the initial step? That is, assume Re = (ideal) 4.0 Ohms, L = 3.5mH or 4.0mH for the first component.
2) With Re = 4.0 Ohms, the 3.5mH and 100uF produces Q = 0.676, while 4.0mH and 87uF produces Q = 0.590. Which one is more preferred?
I know the process should involve measurement, however, I also believe the calculation could be performed before measurement (for some people) as well.
If you look at the response and see it needs no boost or cut, then Q=0.5 gives you a LR2 filter. If the response needs boost, a higher Q is preferred.
Until you know the end result, how can you say which is better?
Until you know the end result, how can you say which is better?
