baffle diffraction correction and crossover network.

[Aucosticraft]

I am designing satellite speakers. this has one tweeter, mid woofer.
I mid woofer is 4 Ohms. so I designed crossover to suit 4Ohms driver. Now the upper cut off is at 3.5KHz and lower is 100Hz. Baffle diffraction correction is at 1 KHz. now my problem is, if I connect correction circuit between driver and crossover filter. Then the impedance of driver seen by crossover is frequency dependent. So this might lead to improper functioning of crossover filter.

Am I right? What Do I do ?

[rho]

A loudspeaker x-over network is always frequency dependent. A loudspeaker is not a resistive load.
Besides that you have to take into account that there is no speaker with a perfect frequency response. So a theoretical calculation, based on a 4 ohm resistive load will yield results far from reality.

[Aucosticraft]

Originally Posted by rho

A loudspeaker x-over network is always frequency dependent. A loudspeaker is not a resistive load.

I agree, and So we use impedance matching ckt.

But still its with Baffle correction, in my case, filter network will see 8 Ohms for higher frequency and 4 Ohms below correction frequency ( it will be gradual change from 4 Ohms to 8 Ohms).

[Aucosticraft]

Just one reply? no one ?

[Bob Brines]

Originally Posted by Aucosticraft

Just one reply? no one ?

Probably because most posters here are into single driver speakers and the word "crossover" is only spoken softly.

Bob

[Keriwena]

Assuming I understand what you're doing....

Let's say you have a plexiglass tube, 3" x 12". You want to fill it 1/2 full of yellow water and 1/6 full of red water. Your questions equates to saying, "After I pour in the yellow water and start pouring in the red water, it mixes and makes orange, so I can't see how much red water I've added."

You can't "stack" passive filter sections. The inductor in your crossover will combine with the inductor in your baffle correction circuit and you'll get one roll-off, not two.

[Aucosticraft]

@ Mr. Keriwena ,Have a look at the diagram attached, and try to understand the difference. ignore the value of components.

[Keriwena]

Ah, yes, now I understand. You don't have a Zobel.

Maybe this 3rd order low pass looks familiar:



I'd follow Rod's advice, myself:
Baffle Step Compensation


And that's Miss Keriwena to you.

[Aucosticraft]

Well Miss Keriwena, (hope I am correct this time. ).

I am using zobal network but just did not put here. just for better understanding.
Compare the circuit again its not same..

[Aucosticraft]

Rod has put a lot good words on Baffle Step Compensation (BSC). Rather I say he has put lot of explanation on Audio. His site is one of my favorite bookmark.

I am looking for a deeper explanation. A simple question for you, which two sides would you use? so would say other two sides ( of four sides) has no effect on BSC ?

I got some link more on BSC. read it too.

I use Edge for deeper calculations.
Still the actual curves are nearly same. I wont say you strictly need Edge. but its better.