Two more great features I just discovered while plugging a mic into the system. Channel 3 and 4 have a combination XLR/1/4" plug so you can plug additional keyboards or guitars or mics using 1/4" plugs here. Also, the first 4 channels have a line/mic switch so you can use any kind of input here. I also just played with the built in SPX effects and the Reverbs are great. Yamaha has now given a reverb intensity knob on the first 4 channels and a master reverb on and off as well. The old model only had on and off on each channel and a master control.