Building an Audio Analyzer with Matrices and Mega2560 / Uno and FFT and Op amps

I hate op amps that need that negative supply i.e. 741

There are many ways to use an opamp in single rail application - the devices don't care whether it is used in dual rail or single rail. All it cares about is differential potentials so there is current float.

Issues come around in interfacing with signals referenced differently. The dual rail solution happens to be the simplest in that department.