Electronic L-R Xover 12db/Octave 5V single supply

This is a 2-way Linkwitz-Riley electronic crossover, working on 5V single supply, designed to also provide some gain.

The need for this crossover came as I wanted to design a battery powered small Bluetooth speaker boombox.

The boombox has two small drivers, one full range which has good performance up to 4-5Khz, and a tweeter which enhances the higher frequencies. The drivers are powered by a 5V dual pam8406 amplifier, using one channel of the amplifier for each driver.

So I needed a crossover to separate the frequencies for each channel of the amplifer. As everything else works on 5V, I wanted to come up with a 5V design for the crossover as well.

The schematic is based on "Elliot Sound Products" project 81, which is a Linkwitz-Riley, 12db/Octave dual supply crossover.

The original scematic was modified to work on single supply. In addition, I chose the mcp602x opamps cause they are audio quality, 5V rail-to-rail opamps.

The first stage was also modified to provide some gain cause the signal level of the bluetooth is relativly low and there is room to add gain, to reach the maximum input sensitivity of the pam8406.

The mcp6021 which was used for the first stage, was also proved practical as it provides the necessary half-supply reference.  

With the given values or resistors and capacitors, the first stage provides a gain of 2.5 (about 8db) and the crossover frequency is at 4822Khz.