# D'Appolito Crossover Calculator

the reverse calculator is
also available
This calculator was developed to help our customers to change a standard 2 way system (1 tweeter + 1 bass driver) into a 2 way system with 2 bass drivers that are often surround the tweeter (D'Appolito arrangement).

Now the question arises: how to change the crossover?

Regarding the bass driver:

That part of the crossover that serves the bass drivers needs to be changed as follows:
- the coils' inductance needs to be halved (therefore, 2 coils are in parallel)
- the capacitors' capacitance needs to doubled (therefore, 2 capacitors are in parallel)
- the resistance values need to be halved (therefore, 2 resistors are in parallel)

Please bear in mind:
The coils should have a wire diameter that is 1.4 to 1.5 bigger.
The resistors should have double the load-carrying ability.

Regarding the tweeter:

That part that serves the tweeter remains unchanged with regard to coils and capacitors.

However, the output of the tweeter needs to be increased by 6 dB. To achieve this the resistors have to adapted. The picture below shows on the left how a system with one bass driver should look like, and on the right how it should look like with 2 bass drivers. Just enter the impedance of the loudspeaker and the values of the two resistors on the left and click calculate.

 2 way loudspeaker with one bass driver D'Appolito Level Calculator High Frequency Circuit 2 way D'Appolito with 2 bass drivers ------------> Impedance of tweeter: Ohm Please enter decimal separators as "." Serial resistance Rs: Ohm Serial resistance Rs: Ohm Parallel resistance Rp: Ohm Parallel resistance Rp: Ohm Damping: dB Notes regarding the result: Damping: dB Total impedance: Ohm Total impedance: Ohm further hint: Please choose a resistance with adequate load-carrying ability. © Lautsprechershop Daniel Gattig GmbH, 2002. All rights reserved - Warranty excluded