Rene Nieuwburg wrote:
>
> Someone can give me information how to design/calculate a passive
> crossover network for a speaker system. I would like to a 12db/octave
> filter with a higher crossover frequency as you normally see on the
> market, around 4 khz
>
> Please CC to my Email address
Rough & ready way to design HP or LP half of 12 dB / octave crossover, where
configurations are as shown:
HP: LP:
|| .-. .-. .-.
PA Out ---||------ PA Out --- () () ------
|| | |
| |
---*--- ---*---
| | Tweeter | | Woofer
) _|_ | _|_
< | |/ === | |/
) |___|\ | |___|\
< | | |
) | | |
| | | |
---*--- ---*---
| |
__|__ __|__
___ ___
_ _
Assume that the impedance of the speaker at the desired crossover frequency,
in each case, will be close to its DC coil resistance. This is not a
spectacularly accurate assumption in all cases, but won't be too far off.
Then, pick L and C for each case so that the reactance of these components is
equal in magnitude to the speaker impedance at the crossover frequency (C = 1
/ (2 * pi * f * R) and L = R / (2 * pi * f)). This will give you high and low
pass filters that are within "spitting distance" of being critically damped.
Picking vaues in this fashion will give you a crossover that will work well
enough for most practical purposes. For a more accurate and finicky design,
suggest you make careful measurements of speakers' impedances vs frequency,
come up with model for each, have a go at filter transfer functions, either
paper, pencil, and algebra, or with Spice, MatLab, MathCAD et al.
Good Luck!
W Letendre
Dir Eng
NEAT
Date: 21 Sep 1998 17:08:26 GMT
Original Subject: Re: Passive crossover design