Chest in the basement of Potos Village changes music:

456B-8F48 + ??6B-8F18

D F 4 7 0 9 1 5 6 B C 8 A 2 3 E

00 = Desert
01 = Flight Tune 1
02 = Flight Tune 2
03 = Flight Tune 3
04 = Boss Battle
05 = Wilderland 2
06 = Lofty Mountains
07 = Requiem
08 = Potos 2
09 = Kakkara Town
0A = Upperland Forest
0B = Waterfall Grotto
0C = Dark Lich
0D = Empire Town
0E = Wilderland 1
0F = Pandora
10 = Mana Palace 
11 = Color of the Summer Sky
12 = Save Point
13 = Legend (Sage Joch)
14 = The Orphan of Storm
15 = Eight Ringing Bells
16 = Matango
17 = Victory Fanfare
18 = Boss Explosion
19 = Cannon Fire
1A = Shooting Through The Air..
1B = Thanatos
1C = Lighthouse
1D = Water Palace
1E = Mana Palace Rising FX
1F = Dwarf Village
20 = A Strange Event
21 = Fanfare 2
22 = Fanfare 3
23 = Fanfare 4
24 = Crystal Forest
25 = Aboard the Sandship
26 = Emperor Vandole's Domain
27 = Pure Land
28 = Flammie Drum FX
29 = Dyluck
2A = Water Palace 2
2B = Game Intro
2C = Secret of Mana
2D = Angel's Fear
2E = Fanfare 5
2F = Fanfare 6
30 = Fanfare 7
31 = Mana Fortress
32 = Ending Tune
33 = Thanatos' Transformation
34 = Memories
35 = Fanfare 8
36 = Pinnacle of Destruction
37 = A Mana Beast Approaches
38 = The Mana Tree
39 = Prayer of the Arctic Circle
3A = Sprite's Sorrow
3D = * Sound Off

C1 = Major Echo Fanfare :)