Do you have a question about the MTX Thunder TS5510-44 and is the answer not in the manual?
A 4 Ohm speaker wired directly results in a 4 Ohm load.
Two 4 Ohm speakers wired in parallel create a 2 Ohm load.
Four 4 Ohm speakers wired in parallel create a 1 Ohm load.
Three 4 Ohm speakers wired in parallel create a 1.3 Ohm load.
List of parts and dimensions for constructing a sealed enclosure.
List of parts and dimensions for constructing a vented enclosure.