I have to design a spectrum analyzer that takes a normal audio input and creates a 4 band spectrum display.
My current plan to accomplish this task is to construct 4 band pass filters centered around the 4 frequencies that must be visualized. The audio input will be split into 4 identical signals via the use of 4 voltage followers (So as to ensure that they do not effect each other). These 4 signals are then each fed into a separate band pass filter. These filters then feed their output into a TI LM3915, which compares the input voltage against a reference voltage and then turns on between 1 and 10 of the output's. These are then fed into DIL Bar Leds for visualisation.
My question is: Does this seem like a legitimate method for accomplishing this, or am I way off the mark? And if it is a legitimate method, what improvements/flaws do I need to take a look at?
Side Note: I've seen the MSGEQ7 chip, however I have 4 specific frequencies that my analyzer must be centred around, so if anyone knows of an IC that can do this it would be even better.
Side Note 2: I can't supply a PCB schematic as this is for assessment.