Crossover design questions

[shmb]

Hi all,

I bought a DIY 2 way speaker system using Vifa drivers and the crossover network puzzles me. The system sounds fairly balanced and smooth so it seems to work.

Anyway here is the schematic, I couldn't read the value of the bottom inductor but it is definitely between 1mH and 1.8mH.



Main questions are:

-Is this some sort of series crossover?

-Looks like a 1st order HP? Or is there something in the path back through the woofer?

-Dual inductors on the woofer? Bass enhancement maybe?

Please help, I wan't to know what they were thinking.

Thanks.

[DougL]

I am no expert, but it looks like a second order Series crossover.
The First order is 5.5Uf across the Woofer and .56 H across the tweeter.
The other Cap in series with the tweeter gives the second order roll off.
Ditto for the Other Inductor.

I know that series crossovers model in Soundeasy (I have done it),
The Series crossover in the Modula MT drove my brother crazy.
If it works, so much the better.

HTH

Doug

[wolf_teeth]

I concur- 2nd order SXO.
Wolf

[VaNarn]

The circuit of the xover is for a second order series layout as DougL says,however the component values do not appear to correspond to text book values.Perhaps knowing the speaker impedances would provide more clues.

[shmb]

So its just a conventional series type second order xover?
Ok, I just thought there might have been some other ideas in there too.

Thanks.

Drivers are the well known Vifa P17WJ-00-08 and D25AG-35-06.

[tvrgeek]

Originally Posted by VaNarn

The circuit of the xover is for a second order series layout as DougL says,however the component values do not appear to correspond to text book values.Perhaps knowing the speaker impedances would provide more clues.

Yes, yes, yes. The combined result is the acoustic response (drivers , placement, and baffle) added to the electrical network that includes the driver model ( far more than the inductance, D'Appolito has a decent model). A book crossover is just a place to start. It will never be optimum.

[shmb]

So what is the advantage (if any) of using a series x-over over a conventional parallel type one?

[wolf_teeth]

Originally Posted by shmb

So what is the advantage (if any) of using a series x-over over a conventional parallel type one?

I don't know that it is an advantage. Some designers swear by them, but it's really only another means to an end, or another way to skin a cat.
Later,
Wolf

[VaNarn]

For passive circuits,a parallel second order crossover is a better choice if the issues of phase and signal summation are not a priority.The reason for this is that the high frequency driver receives some damping via the falling impedance of the parallel connected inductor in the crossover region and below.This does not happen with a parallel first order (or the // third order).I would agree with tvrgeek that a text book design is just a starting point and that the acoustic response and measurements are required for a proficient design.

[PeteMcK]

re:"what is the advantage (if any) of using a series x-over over a conventional parallel type one?" - for 2nd order,none: Series vs. Parallel Crossover Networks