i believe this is what you're looking for

https://www.hondacivicforum.com/foru...ad.php?t=28803



oh and a tip for bracing your sub box... you can do what i did to keep it from moving around in the trunk.
I bought an eBay rear strut bar, and then made brackets out of some flexible metal and trunk carpet (the carpet leftover from cutting holes in the carpet for the strut bar) for padding to keep the brackets from rattling.

here it is in my old civic (i did the same thing in my del Sol but the civic pictures are probably more relevant to your application)

 

i just threw some 3M industrial velcro under my box but my box is extremely light.

 

well if you want to keep the box from rolling around you really need to tie it down some how.... ive used two different things for mine in my civic... just some strong rope and screw it to the side of the box and then run it around one strut, then down and under middle brace for the floor, then around the other strut and screw the other end of the rope to the that side of the box. very easily... ive also use some ratchet straps to hold the box down and crank them tight.

not only will it keep the box inplace but it will also keep the box from hitting other items or falling over with some crazy driving or panic stops.

 

the velcro planted my box it doesn't budge at all but like i said my box is really light.