Designing a Crossover...

[Wheels]

I understand XOver basics, but I don't understand how to design one for a pair of speakers and make it sound decent. I get lost trying to figure finished rated power output and how to match the spl levels of the speakers. oh yeah, I am guessing that the speaker property used in the calculations is the impedence (Z)?

my spl knowledge is limited, i understand that a 3db difference changes the intensity by a factor of 2, but it pretty much stops there.

any examples would be great too.

Thanks
Wheels

[TacoD]

Most people use a software simulator to simulate x-overs. Take a look at speaker workshop.

[Finleyville]

Also, do not wish to be a spoiled sport, but the most successful designs published here use actual test data for the simulations instead of published data. That way they can hear and test their design in their spec'ed baffle and enclosure dimensions.

This is not to say that a design modeled on published data cannot sound good. It is just that there will be more trial and error to make it work. That's all. Happy designing!

[cjd]

Software goes a looong way.

Impedance is only one of the things (though if you're looking at base calculations we're fundamentally manipulating impedance in a crossover)

I don't think you can look at a graph and know how it will sound till you've heard how things sound and seen what causes it, a lot... i.e. experience with bad choices on your part.

You've given us very little information on what you're actually trying to do. There are tons samples on this site - if you just want a great set of speakers, you can pick a design and not worry about it. If you really want to learn crossover design, hang on - it's a bumpy ride. And long-ish.

The book "Speaker Building 201 " is recommended.

[BobEllis]

I'll second the recommendation for Speaker Workshop. While not the cat's meow the price is right and it does what you need to do - model and measure.

Matching driver output levels is fairly straight forward, the matter of a resistor or two. There are other ways to do it, but an L-pad is pretty straightforward. There are calculators on the web, and IIRC Speaker workshop has it built in - tell it you want an L pad and how much attenuation you want and it creates the appropriate pad.

Personally, I don't give a hoot about the rated power of a speaker. In home use, it is usually driven by the woofer and how low you want to go. If you are like most and using a sub and value you continued ability to hear, in most cases you won't run into trouble.

A lot of designs will hit the woofer's xmax with a lot less power than the thermal limit you see published. If you size the amp for that power limit you'll likely run into clipping which will potentially damage your tweeters. I go with high powered amps to avoid clipping but am judicious with the volume knob.

CJD hit the nail on the head - learning to design crossovers is a fairly long process. You will likely go through several iterations and spend a lot of money on caps and inductors learning. It is rewarding when you get it right, though.

[Wheels]

Thanks guys for the response.

Mainly I was just trying to learn more about XO's, but I am getting ready to do a PA speaker build and was trying to get a head start. I will be starting a thread on the design for recommendations within a couple of weeks and I didn't want to have to learn the baisics there. We have to get more of the budget figured out before I can get too serious with the speakers. I will defintly be wanting help designing them.

[cjd]

Designing for audiophile listening is different than designing for a venue (though crossover basics and the math don't specifically change). Nothing like adding even more to the challenge.

Can you be more specific about where you're located?

[Wheels]

Northeast Oklahoma

[cjd]

Oh sure... I don't know if anyone else is out there Might be helpful if so.

[Wheels]

Thanks for the thought, I hadn't thought of that.