What is the difference between 4 pole and 2 pole and what is the difference in sound?
A 4 pole filter filters more than a 2 pole filter. A 4 pole low pass filter will remove highs at 24 dB per octave. A 2 pole low pass filter will remove highs at 12 dB per octave.
In addition to what Brian T said, the fewer the poles, the brighter the sound.
Some other well know filters are 2 pole so if you are trying to get something more like a Oberheim Sem sound or MS-10/20, they used 2 pole filters. Not that an LP is going to sound like the afforementioned synths but in 2 pole you’ll get closer to the filter response than you will in 4 pole.