What synthesizer should i use?
If you're on a budget try a Yamaha. But usually FL Studio has some effective VST plugins like Sytrus & SimSynth standalones that work like a midi instrument but with half the price.
What IS a synth?
If you can play a piano and have some ability to follow instructions from a manual you can play a synth. The advantages; you can recreate just about any instruments timbre, plus discover some interesting sounds never heard before. Your missing a lot ...
Synthesizer Speakers?
Every speaker will work, get an adapter for 1/4 jack to whatever is needed for your speaker. By the way the unit is mislabeled, it's not a synthesizer because it won't let you edit it's sound. Check out the sh201 in the same price range from Roland f...