In manual it says that you can use only 3 triggers (means 3 arpeggiators
and 3 tracks) , but how comes that those written riffs can usage 16
different beats on 16 tracks --------------------------------------------------- I am wondering where you saw this. I search XL-7 Manual G for the word triggers. The only place I saw 3 triggers mentioned was in the "Instant Gratification" section where there is an example using 3 triggers to play 3 arpeggiators.
"15. Now press Trigger Buttons 1, 2 and 3. You should be hearing three arpeggiators playing at once." (page 41 of the pdf)
However, this is just an example.
Also, using the word tracks there is misleading. The sequencer has 16 tracks, but each track can have up to 16 channels of midi data (C01A ->C16A or C01B->C16B). The E-Mu can have up to 32 different arps sounding--one for each midi channel on the two ports.