ive made this shelf for the gt4-12 jbl 1000w speaker i have but i decided to add 4 more speakers to it. I added 4x 200w speakers to the shelf powered by a mrp-m350 alpine amp and it sounds ace u can feel the thud from inside my house when the bass kicks in ive not had it on full max yet. I was wonderin ive made a sealed box made of mdf ive screwed it tight and sealed it with silicoan seal if i place the box under the jbl speaker to creat a boom box /parcel shelf will this make the bass more tighter or shud i not bother
