several questions

[patcheswfb]

i am building a pair of speakers consisting of a 12" woofer and horn tweeter in a trapazoidal prysem shape out of oak with an approximate volume of 60 liters. I want the crossover to be at 19000 hz. what equations would i use to figure out the values of the capacitor and the inductor for a full first-order network crossover (one capacitor in line with the tweeter, one inductor in line with the woofer)? the woofer is 8 ohm, i dont know the tweeter's resistance (i tried using an ohm meter, but it gave me infinate). Also, how would i calculate how long the bass ports should be? I am thinking two 5 cm ports, one on either side of the woofer at the bottom.

[killerkowalczyk]

Im pretty sure you would want the cross over at 1900hz, but my advice to you is to buy Speaker Building 201 by Ray Alden

[patcheswfb]

oh, yea, typo, sry. 1900 hz.

[Chris Roemer]

> i am building a pair of speakers consisting
> of a 12" woofer and horn tweeter in a

This is only OK if you're not after a Hi-Fi design.

> trapazoidal prysem shape out of oak with an

Solid woods are also not usually a very good idea. They'll warp on you. Use PB of MDF with a hardwood veneer on the outside.

> approximate volume of 60 liters. I want the

The proper interior volume for a woofer depends on the 2 T/S parms for Vas and Qts. You can't just guess at a volume (the odds are against it working).

> crossover to be at 19000 hz. what equations

You PROBABLY mean 1,900 Hz (NOT 19,000 Hz) right? NO equations will give you the right result if your decimal point is off by ONE position.

> would i use to figure out the values of the
> capacitor and the inductor for a full
> first-order network crossover (one capacitor
> in line with the tweeter, one inductor in

For a 2-way, you will probably NOT get hardly ANY rolloff of the woofer using a single inductor. To force it to roll off at fc you almost always need to add a Zobel or make it 2nd order (with a shunt cap). Also, you almost always need a minimum of a 2nd order on a tweeter to preclude distortion and possible burnout, not to mention an L-pad for attenuation.

> line with the woofer)? the woofer is 8 ohm,
> i dont know the tweeter's resistance (i
> tried using an ohm meter, but it gave me
> infinate). Also, how would i calculate how
> long the bass ports should be? I am thinking

Again, your odds of just accidentally guessing at the right box tuning is about 1000 to 1. Get WinISD for free at <A HREF="http://www.linearteam.org">www.linearteam.org</A> to answer your box questions.

> two 5 cm ports, one on either side of the
> woofer at the bottom.