We really do need to see a schematic (including the filters).
Is the Arduino involved at all? The Arduino's analog inputs are easy to use and the Arduino can drive a couple of "regular little" LEDs without transistors.
You can test your microphone preamp and filters by plugging the analog output into a power amplifier (AKA "speaker amplifer") and speakers (or headphones). Or if you have regular "powered" computer speakers these will work with your microphone preamp.
If you do this, keep the speakers away from the microphone to prevent feedback!
Do you really want to use a microphone to pick-up sounds in the room? It's often better to tap-into a line-level (or headphone-level) audio signal. You have to be careful with "high-power" speaker outputs.
If you do use an audio signal into the Arduino it has to be biased because the Arduino can be damaged by the negative-half of the AC audio signal. (The preamp schematic you linked to already has a biased output). This post shows the standard bias circuit, which is just 2 equal-value resistors and a capacitor. If you use high-pass and low-pass filters into two Arduino inputs, each input needs a separate bias circuit.
Note that the DC bias is "zero Hz" so a high-pass filter will filter-out any existing bias (so it will have to be added-back between the filter and the Arduino).
Ahhh... THE BIAS FROM YOUR PREAMP IS PROBABLY BEING READ AS "BASS". You'll need another capacitor as a high-pass filter that blocks the zero-Hz DC bias but lets-through the bass signal.
P.S. A high-pass & low-pass in series makes a band-pass filter. For example a filter that passes frequencies between 20Hz and 200Hz will kill the DC bias and the high frequencies while letting-through the bass.
Of course, the DC bias is "automatically" filtered-out with the high-pass filter.