Thanks to the original maker: khoitran, the design looks great.

I wanted to stand my bookshelf speakers at the base of my sim racing rigs monitor stand that's made of 4080 aluminium profile.

I used his unibody file, changed the dimensions to 240x78x249 and to make it more stable i added two holes to the rear that are just the right size to take 2 M8x16 bolts.

Reducing the width to 78mm and making it taller made it less stable sideways but it seems strong enough with 6 walls and 25% infill.

Supported dimensions for the speaker measures: 78 x 207, don't knock your speakers and you should be fine :)

Parts, optional:
2 x M8x16 socket head cap screw (SHCS)
2 x M8 T-nuts