hi
I want to install two speakers which require a 130mm diameter hole. The speakers need to be installed onto a surface which has an enclosed space behind them with some volume (ie, no good installing in bulkhead, as nothing behind them). In the photo below I have found what I think might be a good spot (see circles in red), which is a fibre glass panel at the bottom of the bulkhead. The volume is made up of the whole area under the V-birth.
My question is, structurally, is it unwise to drill 130mm holes in each side in this location of the boat, I think the glass is at least 4mm think. I was thinking I could use a ply backing which also has a whole in it to give a bit more rigidity.
Acoustically that is not a good location for your speakers, the sound could be somewhat muffled and even worse if people were sitting on the settees. A better location is the timber bulkhead where the cabin sides meet the deck.
I am aware that location doesn't meet your specs but a solution would be to fit something like these speakers, no hole cutting, only small screw holes and no need to worry about structural integrity.http://www.ebay.com.au/itm/3-Way-Outdoor-Indoor-Marine-Commercial-Waterproof-Sound-Audio-Speaker-Speakers-/390464180609?pt=AU_Hi_Fi_Speakers&hash=item5ae97a9181
Holes generate a "stress raiser" in the surface, which may possibly lead to failure, Windward Passage 2 had this occur with holes in the deck (I think for a compass?). In your case, the main structural area is probably the bulkhead, and your boats much smaller with less applied loads.....! If you increase the strength with some glassed or epoxy glued 8mm marine ply behind the hole you should be OK. not sure how hard it is to access to do this.
Only other concern maybe that the area you have indicated looks to be a water tight area for buoyancy area. Putting speakers into this space will compromise any air tight space you may have there. Not sure if this is really an issue. Nice tidy cabin. Looks great.
Thanks loosechange and fiesta
You are right, the location is not the best, but I have installed reasonable quality speakers in the parcel tray of sedans before and if you mount them solidly, the volume in the boot gives them a nice resonance. Hopefully that will offset the crap position.
The void is not water tight but could easily be, not sure why they never buoyancy into yacht design back then, but seems like a good idea. Guess that's where insurance and an epirb come into play ;)
Why not install them under the settees. I did this in the Boomerang and get great acoustics. If you use the storage under there you will have to be careful as I found out. Occasionaly the wires on the back will get knocked off.
Select to expand quoteshoodbegood said...
Northshore 27, beautiful little boats, enjoy!
Thx
Select to expand quoteslainte said...
Why not install them under the settees. I did this in the Boomerang and get great acoustics. If you use the storage under there you will have to be careful as I found out. Occasionaly the wires on the back will get knocked off.
Yes, I did consider that, out of the way there I guess.
I use 3 way bass reflex speakers mounted on the bulkhead in about the spot above the shelves in that picture, they might fit in that gap. I bought them from the Salvos op shop, $10 a pair. Superb quality book shelf items. The reflex vented bass enclosure gives a stunning performance. The Salvos here always have a good turn over of quality units.
Excellent idea Ramona - wish this thread had come up before I spent many hours making (sanding, filling, varnishing) a pair of timber speaker enclosures to mount on the bulkhead :(
Select to expand quoteDatawiz said..
Excellent idea Ramona - wish this thread had come up before I spent many hours making (sanding, filling, varnishing) a pair of timber speaker enclosures to mount on the bulkhead :(
Often dead pensioners have really top class equipment. The really good stuff gets taken by the workers but in my local there is always a choice. I was so impressed with the performance of mine I went back and bought another pair for my sail room.
