Which Steps for Conversion from a passive to an active equalization Network ??

[tiefbassuebertr]

If there is a good suited passive correction network between amp output and a full range loudspeaker connections, and I want to transform this in an active network with operational amps, which method I must used ? And which topology ?

Mostly such desires comes up, if there is a big and expensive inductor necessary to purchase (in case of a passive network).

In the attachment an example: two frequency responses from a Fostex FE206EN in a 100 liters vented boom box (BB4) according
BB4 Loudspeaker Analysis
- one without correction network and one with an appropriate correction network.
As clearly to see, there are no frequency aeras, where an enhancement is necessary. Only an attenuation is realized.
Schematic and simulation results of the correction network you will find by post #7 about
fostex FE206En

How looks the appropriate active network (resp. passive network in front of the power amp), that brings me the same results in order to the frequency response?

Thank you for your advices.