Sub for Tangband W3-871S ?

[Kees]

I made loudspeakers with the Tangband W3-871S.
Sound great but need more and better bass.
I am thinking of making a sub with either a 8 inch Alcone 8 HE or an 10 inch Alcone HE.
Will the 8 HE be enough for a room size of 9 x 4 m ?

 

[Naudio]

get the 10 or a 12

u will get lower bass