I cut a lot of holes for mounting speakers in custom cabinets I build. For this process, you will most likely need to use your utility knife. I put exciter speakers in each corner of the cockpit of my boat: Dayton Audio - DAEX19QLP-4 Quad Feet Low Profile 19mm Exciter You don’t have to cut any holes, they are cheap, and they give good sound through the fiberglass.Poor guy almost popped a blood vessel trying and I got to keep my $100! (Mine is a Ryobi, but takes Roto-Zip bits. I was ready to cut the holes to fit, but these speakers fit the 5" holes with no modification. Fasten #8 1 1/4" screws in to your pilot holes until box is secure. In this guide we are are building a simple box to show the process of working with speaker rings and glass mat. This is at least as strong as the "beefed up" fiberglass that wakeboard boats have, and most likely quite a bit stronger. This tool cut through all of that as cleanly as all of the rest - excellent work for large holes. Do not mount the speakers on surfaces with concealed hazards, such as electrical conduits or plumbing. You will definitely be needing the Fiberglass Glow Bit Repair Kit (Available on Amazon). Switch out with carbide bits (sold separately) to cut through plaster, ceramic wall tile, cement board and fiberglass. Place the chartplotter in the hole, and make sure that the mounting holes on the chartplotter line up with the pilot holes on the flush-mount template after cutting, sanding, and filing the hole.
The 6x9s came with 2 bezels and I only needed one, so I used the 2nd bezel as a cutting guide for the hole as the inside edge of the bezel is exactly the same as the hole size needed for the speaker.
How will you decide speaker placement? (Will you cut holes in fiberglass, or mount with screws?) What amplifier and wattage is best for your electrical system? What wattage speakers (and ohms) work with your amplifier? Do you want subwoofers and if so, what size can you fit? (And will you cut holes?) Is your wiring up to snuff for the marine.Use bondo and polyester primer to finish the smoothness for painting or just use bondo if you are going to vinyl or carpet the project. I took it down to West Marine and offered a salesman a $100 if he could pull the SternSaver off the cutout. This high gloss white fiberglass boat speaker box looks great and were designed with the JL Audio M770 and M880 speaker in mind. I have room behind the fiberglass for the speaker. The speaker installation instructions should spell out minimal space requirements and other such requirements for best performance.
What do you suggest I use to cut the holes? Router with a template guide? RED is current placement BLACK is possible speaker placement BLUE is Poor guy almost popped a blood vessel trying and I got to keep my $100! When cutting holes in the bracing, leave at least 1" between the hole and the edge of the brace, and when using multiple circular holes it is best to have the holes staggered for more strength. The cutting and drilling Set the depth of the cut just enough to shave the phenolic off without cutting into the plywood.