Along with progressing the players along Project Lied, songs can also be used to perform spells. The Spell shop located on the Shop board is where a player can purchase one of these Spells, a sheet of music, for bits. Many of the spells can be played with a single instrument.
Spells require a certain amount of Acoustics, a scoring system for instruments. Some require only 1 Acoustic, meaning each instrument can play it. However, many require more Acoustics. Some instruments have stronger sounds, allowing these spells to still be played by one instrument, but some players may need some help. Spells can be collaborated so long as one of the players has the spell bought. This means that a 3-Acoustic spell can be played with three 1-Acoustic instruments.
Some spells, however, also require certain kinds of instruments. A spell may be only played by a String instrument, while one spell may need both a String and Wind instrument. Players will be required to combine their efforts for stronger spells, in both Acoustic count and Instrument Type.
You do not need to hit an exact number of Acoustics to play a spell, so long as you go over. For example: two players with a 2-Acoustic instrument and a 3-Acoustic instrument can play a 5-Acoustic spell.