I can understand wanting a deliberate mix going lo-fi, but having the basics in hi-fidelity allows you pare it to the sound you want and still retain the audio clarity. Running well recorded tracks back through a myriad of odd sounding devices is a way to achieve this.

Finding an older vocorder or a synth module of the analog variety and running a signal through it would allow you to manipulate the the frequencies and the modulations.....using stomp boxes on tracks....finding a decent cassette multitrack recorder and recording certain parts and then editting and time aligning with your program....

All these things are all about being experimental.....but having FIDELITY in your lo-fi gets it more listenable than a simple lo-fi recording with no fidelity.

I sometimes use some of logic's distortion effects to add a little dirt.

I oftenly use my old nagra recorder to tape things. And then play them through its tiny speaker and mic that back...
Works like a charm...