A horn question

[Duke Spinner]

its been 30 years since i thought about crossover stuff ...

at 12dB/ octave ....

isn't half the energy above ...

'n half below ...

the center freq ...???

[djk]

The Altec chart is misleading at best.

Those are the recommended crossover frequencies, not the horn Fc.

As stated by PWK in the AU-11 issue of the IEEE(Nov-Dec, 1963), the Fc of the K5J was 300hz, and the Fc of the K400 was 240hz.

The taper rate of the JBL/Altec horns designed for 300hz crossover was typically 190hz, about 1/2 octave lower than the intended crossover point. A full octave would have been better from a response smoothness standpoint, but would have increased the bulk by a factor of 8(2^3), and increased HF distortion as well.

If a horn was flat to its Fc(which it is not), then generally speaking, for a 1dB error in the sum of the woofer output plus the HF output, you need:

Two octaves for 6dB

One octave for 12dB

about 1/2 octave for 18dB or 24dB

A K400 with the K55V drops about 10dB from its Fc of 240hz to 200hz(1/3 octave), and is down about 20dB at 200hz WRT 400hz. All without a crossover.

Introduction of a simple 6dB filter (A or AA network), gives a very complex acoustic transfer function steeper than 24dB/oct.

[Duke Spinner]

Cool ......now, that's an answer

Thanks , DJK ...[]

[sunnysal]

yup thanks, yet another post I will print out and save. tony

[D-MAN]

If you cross a 400Hz horn at 500Hz -- does it still load properly?

I do it everytime I listen to my system! I crossed at 600Hz in a 400Hz horn!

DM

[raypenn]

Dean -

Do you think that you would hear much difference if you crossed at 500 or 700?

Thanks.

[travisc]

Dean -

Do you think that you would hear much difference if you crossed at 500 or 700?

Thanks.

I changed from 600hz to 400hz today with a 511b and there is a huge difference in male vocals.

though I am still confused. type B is a 6dB slope correct?

6dB less per octave(bear with me I am learning)