Hi Sumanta,
Thanks for the reply. Some history on this.
3 years ago I built a 4 way active speakers with the below crossover frequencies
Low pass - 114 (Subwoofer)
Band Pass - 70-900 Hz (mid-woofer)
Band Pass 750-3500 Hz (Mid Range)
High pass - 3500 Hz (Tweeter)
Some details and pics are here
Pics of my new 4 way active filter and amplifier using NE5532 LM3886 and LM1876 - diyAudio
The amplifier used for this is giving lots of loose connection problems now. There are many wires connecting to lots of PCBs. I shifted house and moved the amp many times in last few months. So instead of fixing it every time, I decided rebuild it and minimize wires. I planned to make just 2 PCBs, one for all amplifiers and 2nd for all power supplies, and reuse the existing active filter pcb with minumum changes. To reduce complexity I plan to remove subwoofer section from the amp and remove high pass section of 70-900Hz bandpass from active filter to make it 900Hz low pass and remove all components of 114Hz lowpass.
I decided 900Hz because I already have a active filter with this value.
My existing speakers will not produce much bass without subwoofer, because mid-woofer enclosure is sealed and have very less volume and was not at all designed to produce lower frequencies. So I plan to make a new enclosure and checking options for replacing woofer.
I don't care about SPL, because this is a active setup, I can easily adjust volumes of each amplifier to match SPL of all drivers. Or worst case, I can adjust the gain of output opamp of active filter by just changing a resistor if SPL is too low for any driver.
Thanks,
Anirudha