Let’s take a cap on a tweet.
Let’s assume a nice flat 8ohm load………….. (lol)
The formula C = 1 / ( 2 x Pi x F x R)
So, given 8ohm tweet, 5khz, the value is about 4uF
My question is “Is it 6db down at that frequency” ?
I'm hoping to ghost a tweet in.........................
Norman
Let’s assume a nice flat 8ohm load………….. (lol)
The formula C = 1 / ( 2 x Pi x F x R)
So, given 8ohm tweet, 5khz, the value is about 4uF
My question is “Is it 6db down at that frequency” ?
I'm hoping to ghost a tweet in.........................
Norman
T = R / (R + 1/jwC) normalized HP filter, with corner = ( 2Pi x f ) = w = 1/RC
T = jwRC / (jwRC + 1)
| T | = sqrt ( T x T* )
| T | = sqrt [ [ jwRC / (jwRC + 1) ] x [ -jwRC / (-jwRC + 1) ] ]
| T | = sqrt [ (wRC)^2 / ( 1 + (wRC)^2 ) ]
at the corner frequency, w = 1/RC
| T | = sqrt [ 1 / 2 ]
| T | = 1 / sqrt 2 = 0.7071
20 x log ( 0.7071 ) = 20 x (-0.15052) = -3.01 dB at w = 1/RC or f = 1 / (2Pi x RC)
How's your mom?
T = jwRC / (jwRC + 1)
| T | = sqrt ( T x T* )
| T | = sqrt [ [ jwRC / (jwRC + 1) ] x [ -jwRC / (-jwRC + 1) ] ]
| T | = sqrt [ (wRC)^2 / ( 1 + (wRC)^2 ) ]
at the corner frequency, w = 1/RC
| T | = sqrt [ 1 / 2 ]
| T | = 1 / sqrt 2 = 0.7071
20 x log ( 0.7071 ) = 20 x (-0.15052) = -3.01 dB at w = 1/RC or f = 1 / (2Pi x RC)
How's your mom?
Last edited:
Sheesh! Thanks, never seen the math; now I know why my mentor just said odd orders = -3 dB, even orders = -6 dB.
GM
i guess i'm too much of a Hitchcock fan to ever ask a guy with that name about his mom...
if the assumption of a "nice flat 8 ohm load" where true wouldn't that result in a stepped response?
if the assumption of a "nice flat 8 ohm load" where true wouldn't that result in a stepped response?
That would give the ideal first order crossover curve.
Higher order filters can give a sharper corner, but none can be square.
Last edited:
