A speaker box optimized for SB Acoustic SB20FRPC30-8 requires al least 27 Liters for a sealed enclosure (between 27 and 45 Liters) and if ported requires a more volumed box than a sealed box. Either enclosure will work. However, if you want to go for bass reflex you need around 100 liters of volume. As a result, if you prefer smaller enclosures go for sealed. You can also fill it up with damping material to improve the sound.
