Yamaha SPX900 Operation Manual page 73

EFFECT MODE
SINGLE (No. 1 ~ 37)
MULTI (No. 38 ~ 47)
No.38 ~ 39 MULTI(ECH&REV)
No.40 ~ 42 MULTI(CHO&REV)
No.46 ~ 47 MULTI(EXC&REV)
No.43 ~ 45 MULTI(SYM+REV)
~
DUAL (No. 48 50)