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Old 5th June 2004, 07:13 PM   #31
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Quote:
Originally posted by Ron E
Before you go too nuts with the bass boost, you might want to model excursion. Just because the EQ'd woofer will go flat to 20Hz doesn't mean it will handle much power there.. Make sure to apply boost at the tuning frequency.

Glad you are enjoying yourself!
Good advice. I might also want to learn about calculating phase. Can you recommend a book that has this stuff in it?
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Old 5th June 2004, 09:32 PM   #32
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Quote:
Originally posted by Ron E
Before you go too nuts with the bass boost, you might want to model excursion. Just because the EQ'd woofer will go flat to 20Hz doesn't mean it will handle much power there.. Make sure to apply boost at the tuning frequency.

The tuning frequency is indeed right around 20 Hz. I'm going to change those resistors to move the boost level down to 20 Hz.
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Old 5th June 2004, 09:57 PM   #33
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Quote:
Originally posted by Dave Jones


The tuning frequency is indeed right around 20 Hz. I'm going to change those resistors to move the boost level down to 20 Hz.
... or remove the boost alltogether. I'm going to start another thread. See XLS 10" -- boost?
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Old 7th June 2004, 05:52 PM   #34
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One more question, please Ron.

What's the formula for a 24dB/octave 4th order Linkwitz-Riley crossover?
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Old 7th June 2004, 06:16 PM   #35
Ron E is offline Ron E  United States
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I posted it earlier:

"You can square B(f) and if the crossover Q is 0.707, you get a 4th order Linkwitz Riley slope.
LR4(f) = B(f)^2 = 1/((1-fc2)^2+(fc2/0.707^2))
"

The LR is down 6dB at fc2.

---in LaPlace Notation----------------------------------

2nd order highpass is:
sn^2/(sn^2+sn/Q+1)

2nd order lowpass is
1/(sn^2+sn/Q+1)

sn is normalised complex frequency sn=s/sc
sc=crossover frequency

substitute s=jw

for frequency response:
take magnitude of numerator and denominator
magnitude of numerator or denominator = sqrt(realpart^2+imaginary^2)

for phase response (in radians):
phase = arg(numerator)-arg(denominator)

cheers.....
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Old 7th June 2004, 06:34 PM   #36
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Thanks again. I am trying to find books and so forth on this. It's amazing how little I've found on the net.

I think this is correct for a Linkwitz-Riley 24db @ 100 Hz.
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