crossovers

If a signal goes through an active crossover, the signal has changed.  The -3 db cutoff freqency (f3) also has changed by using the crossover.  If that signal then goes on to another crossover, the new crossover is added to the existing one.  It will change the curve and therefore the f3.  If you add another crossover, it too will be added to the existing ones.  The f3 changes with every change in crossovers.

You could download WinISD and do some experimenting with crossovers.  You can add several crossovers to a project and select however many you like, and you'll see the slope change with the addition or subtraction of the different ones.

I'm just barely familiar with crossovers, but I've gotten that much knowledge by working with WinISD on my own speaker projects.

it just so happens that i allready have WinISD but i havnt played with the xover function that much i didnt know you could apply them to the box curve. thanks for the good idea. when i said f3  i ment the point were the high and low pass signals crossover not the -3db natural foll off of a speaker/box combination wich is also called f3 refer to the crued pic. i put up. thanks for the reply!

pic didnt work ohwell  i hope you understand what i ment by f3 it has two applcations. The minus 3 db point of the natural speaker/box roll off and the point were the high pass and low pass xover slopes cross wich is also minus 3 db and called the f3 of the xover and  is also the freq. of the xover were this happens.  so hard to explain.

You would have to add .jpg to your picture to upload it, so we don't see it.  But I know what you're referring to.  Pick one of the subs in the programs data to work with, then bring it up twice as a new project.  Put a highpass filter on one, and a lowpass filter on the other.  The graph will show both filters used.  Then you can select different crossovers for each one and watch the difference in the graph.

Actually, they don't cross at the -3 db point.  The lines cross at a point near the top of the slope (near 0 db) for a smooth rolloff and minimal loss of frequencies.