2 Way Crossover

[wolfsvein]

What would the crossover point be for a 4 ohm crossover 3000 Hz 2 swy crossover be for 8 ohms speakers attached? Thanks.

[Cal Weldon]

Hold on there partner, there's more to it than that. When you change the impedance by 2X you need twice as big a choke coil and half the value of capacitor to achieve the same XO point.

So all other things aside, with a simple 6dB XO, it will not roll the woofer off until twice the frequency or 6000 Hz, and the tweeter high pass will begin at 1500 Hz.

Tell us what you have and what you want to do, let see if we can help. Maybe a pic or two also.

EDIT: Moved to Loudspeakers

[BlueWizard]

Indeed, it is far more complicated than you might think.

If this is a 12db crossover, meaning one coil and one capacitor of each section (high and low), for a total of two coils and two capacitors for the entire crossover.

If you add an 8 ohms woofer and an 8 tweeter, one component shift up in frequency and the other shifts down.

As an example, 12db/2nd order Linkwitz crossover for 4 ohms speakers at 3,000hz

C = 6.6333 uF
L = 0.4244 mH


Changing to 8 ohm speakers and using 6,000hz

C = 1.6583 uF
L = 0.4244 mH

Changing to 8 ohm speakers and using 1,500hz

C=6.6333 uF
L = 1.6976 mH

So, the coil aspect moves up to 6,000hz

and the capacitor aspect moves down to 1,500hz.

Keep in mind that in the above example, you have BOTH a coil and a capacitor on the Tweeter (and both on the woofer). So, one component of the tweeter crossover will start at 1500 hz and the second component will come in at 6000hz.

Very confusing.


Even is a much simpler 1st order/6 db crossover, which uses one capacitor for the tweeter and one coil for the woofer. The components move in the opposite direction.

The Tweeter (capacitor) shifts down to 1500hz, and the woofer (coil) shift up to 6000hz.


If you need a basic crossover, here is an on-line calculator that can help you determine what you need.

http://www.apicsllc.com/apics/Misc/filter2.html


But it would be better to start by learning WHAT you are doing, then you can determine what you NEED.

The best way to do that is to tell us what you are doing and what you need, and well see where we can take it from there.

Steve/bluewizard

[Cal Weldon]

Geez Steve, you didn't like my answer?

EDIT: Grammar

[BlueWizard]

Sorry, Cal, did mean to step on any toes. Your answer was fine as far as it went. And it was your answer that gave me the idea for my answer. So, thanks.

I just thought I would expand on your statements, and illustrate more clearly what was happening.

I'm aware we said essentially the same thing, but I though if the person could get a better look at the underlying mechanics, it would help him understand why it was happening.

So, I wasn't contradicting or even ignoring what you said, I was hopefully expanding on it.

Steve/bluewizard