Crossover help

[NcHalfrican]

What is a good calculator for crossovers? It's a two way setup but my tweeter is 3~db more efficient than my woofer, so will I need to incorperate some kind of BSC?

[Cal Weldon]

A crossover calculator is only a starting point and will rarely give good results. Here's some reading for you:

Introduction to designing crossovers without measurement

If the tweeter is more sensitive than the woofer, you require an L-Pad.

[AllenB]

Originally Posted by NcHalfrican

my tweeter is 3~db more efficient than my woofer, so will I need to incorperate some kind of BSC?

BSC is not related to a woofer or tweeter, it is applied to the overall system. It amounts to some bass boost below a particular frequency, and for many conventional two-way systems it happens below the crossover frequency and this is just a matter of coincidence.

So assume you have crossed a woofer and tweeter to have a flat overall response. As a result of the BSC chosen, the woofer will have its top end reduced a little further. At the same time, the tweeter needs to be brought down to that same level.

[strawberry]

What is a BSC? Try 2 ohm, then 3 ohm.

[rjbond3rd]

Speaking strictly as a newb, for me it helps to take a look at the ideal scenario, then work backwards based on how your situation differs.

Simplistically, it would be better if your woofer were more efficient than your tweeter, and that you choose a crossover point which happens to be right at the center frequency of the baffle step. Then you gracefully "lose" the woofer's extra efficiency because it's now compensating for the baffle step loss. No padding down of the tweeter required.

This of course requires that your crossover point and your baffle step frequency -can- be the same, that the woofer is indeed more efficient, that the tweeter can be crossed that low (unlikely unless your baffle is really skinny or your tweeter is more like a widebander).

If your tweeter wants to be crossed much higher than the baffle step -3dB point, then your woofer would need a BSC separate from the crossover (or alternatively, just prevent the baffle step loss with flush-to-the-wall positioning like an infinite baffle, or add a second woofer acting as a 0.5 driver, or make the cab compensate by providing gain in other ways, e.g. reflex loading, horn loading, wider baffle, etc.)

[rjbond3rd]

Another way -- not practical necessarily, but just to illustrate what's at work.

Make your cab an undersized sealed box, with a pronounced bump in the response (e.g., a sealed box with a really high Q at least 1.0 but probably higher -- that's really high but it's just to show a point).

Now, is that bump of the right frequency and magnitude to compensate for baffle step loss? Most likely no, so just keep adjusting the dimensions of the box (keeping the same volume) until the "bump" of the undersized box meets up with the baffle step loss. Presto.

I'm not suggesting this will work in your case, it's just another tool in the toolbox, one particular strategy. Putting a big bump via an undersized box has other sonic consequences but everything's a compromise (apparently!)

[PeteMcK]

L pad calculator - attenuation dB damping impedance decibel loudspeaker speaker voltage divider - sengpielaudio Sengpiel Berlin