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-   -   311 sub placement (https://www.offshoreonly.com/forums/formula/168481-311-sub-placement.html)

TylerBurich 09-11-2007 02:53 PM

311 sub placement
 
Hey guys,
I have a question about sub placement in a 1988 311. Has anyone tried putting subs in the spot under the lounge seats in their cuddy? There is the removable panel in the middle that i was thinking about using. But what about underneath the port and starboard cushions???? I can't seem to figure out how to access underneath them. I think this would be a good location utilizing all three areas because i have 3 jl audio 8w3's i'm planning on using. I was planning on modifying the three seperate areas to make them the exact volume jl recommends. Maybe even tune them really low with their recommended port tuning. Question is though, what is under those cushions, how do i get the cushions up, am i nuts????
thanks
tyler

t500hps 09-11-2007 03:38 PM

There is suprising little space under the seats in the fastech boats....and the vertical surface under the seat (front of seat to the floor) is the boats stringers....hope you weren't thinking of putting the speaker faces there facing each other near the floor.

TylerBurich 09-11-2007 04:19 PM

subs
 
Aha, was wondering bout that............hmmmm, wonder if that holds true for the older boats. I would still like to know how to access that area. A friend has a 32 fever with a sub mounted in the middle portion of the lounge seat and it sounded really nice, kinda using the whole cuddy as a bandpass enclosure. i'm beginning to think about putting one sub in the middle section of the lounge area, and the other two under the front seats with gunnel mounted enclosures. Of course i would have to flush them so i could still slide my gunnel storage doors open.

TylerBurich 09-11-2007 04:24 PM

btw, jl recommends .35 cubic feet of air space for each sub in sealed enclosure, and .75 cubic feet of air space for vented enclosure. they want about a 8 square inch vent to tune down to 35 hz. i experimented with three jl's in a previous appication where they shared a common enclosure with one tuned vent.....sounded like 12's. keep the ideas coming, i appreciate it

got twins ? 09-11-2007 04:24 PM


Originally Posted by 454captiva (Post 2267379)
Hey guys,
I have a question about sub placement in a 1988 311. Has anyone tried putting subs in the spot under the lounge seats in their cuddy? There is the removable panel in the middle that i was thinking about using. But what about underneath the port and starboard cushions???? I can't seem to figure out how to access underneath them. I think this would be a good location utilizing all three areas because i have 3 jl audio 8w3's i'm planning on using. I was planning on modifying the three seperate areas to make them the exact volume jl recommends. Maybe even tune them really low with their recommended port tuning. Question is though, what is under those cushions, how do i get the cushions up, am i nuts????
thanks
tyler

Hi Tyler,

I have a 88' 311 as well. I looked the same spots that you are currently thinking about too. What I ended up doing was replacing the front speakers with 6.5s (in the v berth) and in the cockpit on the port side beside the bolster I put a 10" sub with reforcement behind of 3/4" plywood glued to to the storage compartment wall. I also replaced the front speakers same holes w/6.5s and added 2 more 6.5s under the bench seat for rears all components are jl audio ( sounds freak'in awesome) .....
Just another idea if it helps .....

Jeff

TylerBurich 09-11-2007 05:28 PM

thanks for the info twins. I am now seriously thinking about building some enclosures for the same area you installed your subs. according to jl if i build a sealed box .35 cf (pretty small actually) my subs will tune out to 53 hz which is great for the cockpit area. what were the model of your subs, how do they sound down low? when you cut your holes how did you trim them out, sounds like a flush mount install. do the plexiglass doors still slide over them? thanks

handfulz28 09-11-2007 07:32 PM

I "think" the area under the lounge seats in the cabin is filled with foam. I haven't torn out those seat cushions myself, but you've got to really pull the edges up and look around for screws. The front edge material might be screwed in under the carpet.
Also, even if you went gung-ho to get in there, there's a lot less room under there then you think. You could probably get your .35cf, but that's not the area I'd mess with. That front/center compartment could work though. I know next to zilch about audio stuff...would a sub in that location provide good bass throughout the boat, like up in the cockpit?
Keep us posted (with pics if possible) as you progress.

got twins ? 09-11-2007 09:09 PM


Originally Posted by 454captiva (Post 2267673)
thanks for the info twins. I am now seriously thinking about building some enclosures for the same area you installed your subs. according to jl if i build a sealed box .35 cf (pretty small actually) my subs will tune out to 53 hz which is great for the cockpit area. what were the model of your subs, how do they sound down low? when you cut your holes how did you trim them out, sounds like a flush mount install. do the plexiglass doors still slide over them? thanks

All of the speakers are flush mounted. The sub is located at about your left knee on the port side bolster seat maybe a hair lower. There is no problem opening and closing the storage compartments (sliding the plexiglass).It is a pain in the ass but what I did is ... on the inside of the wall I installed a piece of 3/4" plywood by glueing it right to the fiberglass to strengthen the wall once it dried I cut the hole for the sub. It has been solid as a rock .... no vibration no loose screws.... In behind wear that "storage area' is I put all my life jackets (8) two reasons 1) they are soft and not going to damage anything when I am pounding in big water. 2) Acts as a enclosed box for better sound. There is no loss of sound what so ever. Now as you know you need a serious amp to power these speakers to get "clear music" as opposed to loud music. My goal was to be able to listen to anything I wanted at 50 - 60 mph with out distortion or "noise". You can listen to thump'in dance music ie channel bpm on XM or big tracks (rock) on XM it doesn't matter it rocks with the five speakers in the cockpit .... 4 - 6.5s 1- 10 sub. Something else when you hook up your v berth speakers only run them off the deck not your sub .... save your power. 1) You can't hear them anyway when you are in the cockpit. 2) If you are the cabin you turn off the cockpit speakers by turning the amp off.

I don't think you need to make specific "boxes" for you subs if you mount them the way i did.

Good luck

Jeff

P.S. another reason I mounted the sub where I did is you can't see it as much ... people look and can't figure why you thump as much as you can it is hillarious to see peoples responces.

TylerBurich 09-11-2007 09:19 PM

thanks for the info z28, i think i have given up on the effort to put subs under the side cushions. i think i will stuff one 8" jl w3 under the middle cushion for now and throw an amp on it. cool thing about the subs i'm wanting to use is that i can parallel the voice coils on one since they are dual 6 ohm coils and have a small amp push them at 3 ohm load....for now...then later add the other two...series the voice coils (12 ohm load) then parallel them all (4 ohm load). i really don't want to put subs under my rear seat, that's where i stow my anchor and ropes. where in ftl are you z28, i spend at least one month a year in davie

handfulz28 09-11-2007 09:59 PM

parallel...voice coils...ohm loads...might as well be chinese :) I know ohms, but don't know how all that works.
I'm actually up north...near Deerfield Beach. Keep boat in Pompano. Check out www.raft-up.com and let us know when you're in town.


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