Speaker Placement In R33

[ZLLA]

I was given free pioneer speakers that are in a box. I wanted to put them on my parcel shelf but the rear windscreen is on to much of an angle. I don't want to waste them because they sound amazing but i have no where to put them. Anyone got any tips? What about the middle seat? If i can somehow secure them so they don't fly around back there.

p.s I don't want to put them on the floor because that's impractical.

Thanks in advance.

[Chris Rogers]

What size?

[ZLLA]

I don't know what size but the box is about 30cm wide and 25cm tall.