Line level passive BSC

[rhapsodee]

Hi,

To cut a long story short, i built the Madisound RB kit, and realised that i need about 3dB more BSC.

I 'm trying to work out a passive line level BSC between my receiver preout to power amp input (NAD214s). I found this article whcih describes a passive BSC design.

http://www.t-linespeakers.org/tech/b...ssive-BSC.html

My baffle width is 7inches, for BSC Fc about 650 Hz is needed.
NAD 214 input impedance is 60kohm 500pF

With the following values of Rs and Cs (3dB compensation)
Rsource < 2k ohm
R1= 8300 ohm
R2= 20000 ohm
C1= 1.7nF
C2= 11nF
Cload= 500pF

I get these corner frequencies for the BSC.
FC1=723.43 Hz
FC2=511.26 Hz
FC3=11279.58 Hz
FC4=17165.48 Hz

I'm not sure if i'm in the ballpark, or am i way off? The article mentioned R2 should be much less than power amp input impedance. Is 20k too close to 60k?

Help much appreciated!!

[PeteMcK]

Rod Eliott's article shows you how to make the freq variable, that way exact values don't matter so much...
http://sound.westhost.com/bafflestep.htm