New helm subwoofer encloser design help for malibu 247

[CRF-Rider]

Thanks for the input CRF! Yes this is a 15" re audio XXX and it is certainly a big ole sub. I actually cut my slot port out this week and I am fine tuning my port length to get it where I want. I am not doing any internal bracing in the box. As you noted, the slot port actually helps brace the box a little bit and I am going to do a wood support off the bottom of the box to the subs magnet to help support alot of the weight. This is very important when you consider hitting wakes on a rough busy weekend and how much this sub weighs.

As for the lining, I am just going to one of our local after market trucks shops around here and let them spray it. I'd rather not mess with it and it wont take them long to spray the box down. I still need to round all of my corners and sand the box but here is where I am at with the enclosure.

Cool man, seems like you got a good plan going. If it were me, I would forgo the wood support under the magnet. It has to be precise and it's hard to get it precise because you won't be able to see inside the box with sub installed to tell. You're clearly a good wood working though, so may be a non-issue. FWIW my 15" sub is about the same weight as yours, it's installed on a double baffle with 1 5/8" coarse thread drywall screws. It's taken a beating in Lake Austin chop over the past 3-4 years with no issues.

Thanks for your help, CRF. I actually did round the outside edges of the slot... not sure if you can see that from the pics I posted. Are you saying they should be even rounder??

No problem man. Yes, rounder, a pass with a 3/4" roundover bit. Essentially what you're doing is creating a flared port. You want it round and smooth. When the air comes out of the port, sharp edges will create noise. This isn't one of those overkill enthusiast type suggestions...port noise is easily encountered. When you get the box done, play a 38hz test tone and listen for noise at the port.

[rjones]

Thanks for the kind words CRF, I like to to think I can atleast cut some pieces of wood in a staright line lol! I think I am going to skip the sub support like you suggested. With 8 coarse thread screws holding the sub in surely it will be fine. Well I got my port done finally and the box is pretty well done other then getting it lined in the next few days. Here is the finished (bare) product. Will get a video once it is in the boat with some tunes!

[CRF-Rider]

Hats off...well done!

What size speaker wire is that? Not sure how long the run is to the amp, but I'd recommend using 8ga regardless for peace of mind. I used 8ga stinger power wire for mine.

I found that with a high powered sub like yours, the in-boat speakers couldn't keep up with the SPL. I had 8 high end coaxial marine speakers, then tried another brand of high end marine coaxials that couldn't keep up either. I came to the conclusion that coaxials weren't going to cut it. I ended up going with pro audio mids, super tweets, and an amp that was capable of running 2 way active. It definitely keeps up and sounds good doing it. Wish I knew then what I know now, I upgraded my $1k amp/in boat speaker setup with a $400 amp/in boat speakers set up. It'll be interesting to see if you have the same issues.

[rjones]

I was just running some cheap 14 gauge speaker wire to test the sub out. Installed some nice 10 gauge wiring I had laying around yesterday (hopefully this will suffice). You bring up a good point with the speakers being out of sync because one or the other can't keep up. I do not know if this will be an issue but will address it if I run into that problem. As for my sub box, I finally got it lined a few days ago and here is the final product. I am very pleased with how it turned out and it should last for a good 5+ years easy.

[shawndoggy]

but the $64K question.... are you happy with how it sounds?

[rjones]

I am pleased so far but I haven't really ran it to hard yet. It gets LOWWWWW and no port noise yet! I am quesioning if I went to low of a tune because some of the upper Hz (38-45hz) aren't ad loud as I would of expected. This could be all due to me not properly setting my gain and crossovers yet so all in all I'm happy so far!

Once I get some time in the boat this weekend I'll do a comprehensive review so that hopefully others can benefit from my experiences.

[IXFE]

I am pleased so far but I haven't really ran it to hard yet. It gets LOWWWWW and no port noise yet! I am quesioning if I went to low of a tune because some of the upper Hz (38-45hz) aren't ad loud as I would of expected. This could be all due to me not properly setting my gain and crossovers yet so all in all I'm happy so far!

Once I get some time in the boat this weekend I'll do a comprehensive review so that hopefully others can benefit from my experiences.

What did you tune it for?

[rjones]

I was shooting for around 34hz but it came out to around 32hz

[rjones]

So last night I got the sub tucked up in its new home under the dash and luckily all my measurements held true. It was a tight fit but fit like a glove!

I am blown away with the output of this thing and it sounds awesome. When I was testing the sub out at first I used some cheap 14 gauge speaker wire I had laying around so the output wasnt very good. Once I ran some quality 10 gauge speaker wire from the amp to sub the output doubled it seemed like and sounds so much better! Now after I get some good seat time this weekend I will do a review and let you all know my final thoughts. One thing is for certain.....it gets plenty loud!! :clap: :yahoo: I just have to remind myself to be courteous and not piss any of the yacht folks off at our lake.

[Bawshogg]

One point of caution. You see that corner on the lower right hand side pushing into the carpet? Or at least it appears that way in the picture. That's the hull. If your box is screwed to the floor and secure, that right there will be a problem. That point may cause a stress point in the glass of the hull of the boat and may even lead to big ol' spider crack on the OUTSIDE of the boat. You see, the hull flexes....a lot especially when you hit rollers, in out of the water on the trailer, ect. That rigid point will cause the glass to flex around that single point, not a good idea. I only say this from experience.

My first boat had a very similar situation to this occur. It was not pretty , especially when Malibu denied the gelcoat claim and the installer had to pay for the repair.

Looks like you possibly could move it over a 1/2 inch or so??

[rjones]

One point of caution. You see that corner on the lower right hand side pushing into the carpet? Or at least it appears that way in the picture. That's the hull. If your box is screwed to the floor and secure, that right there will be a problem. That point may cause a stress point in the glass of the hull of the boat and may even lead to big ol' spider crack on the OUTSIDE of the boat. You see, the hull flexes....a lot especially when you hit rollers, in out of the water on the trailer, ect. That rigid point will cause the glass to flex around that single point, not a good idea. I only say this from experience.

My first boat had a very similar situation to this occur. It was not pretty , especially when Malibu denied the gelcoat claim and the installer had to pay for the repair.

Looks like you possibly could move it over a 1/2 inch or so??

That is a great point and thanks for lending me some of your past experiences Baws, I certinaly appreciate it. I actually haven't screwed the box down yet. I used some 1/4" rubber mat pieces on the bottom left side and right side of the box to help suspend it off the hull and keep it from sliding any. To tell you the truth, I am still figuring out how I am going to secure the box but with this rubber mat it doesnt seem like it will be moving much at all. I was going to run screws through the bottom panel of my box but I am just not a fan of punching screws right through the hull......especially after hearing about your incident. The sub and box together weight about 95lbs. This is a ton of weight to transfer to a couple screws into the hull.

Do you have any suggestions on mounting?

[Bawshogg]

I do, but not very easily explained here. I usually opt for a tongue and groove setup using aluminum flat bar and angle channel with HPDE feet. I think how your setup is now, and if the box is not at all tippy, a piece of aluminum angle up front with about 4-screws #10 or ##12, across the front panel and 4-6 along the floor would work well. Especially if you are going to do a trim panel that will cover it any ways. Don't be scared to drill into the floor, just don't go crazy. I have measured those floors in several spots and they are around 3/4" thick for reference. So set your drill depth there with a tape marker on the bit just to be safe. Under size your holes a tad for a good bite and add in your material thickness to your screw length. IE: 1/4 aluminum plate +3/4" floor thickness. 1" long coarse thread stainless machine or wood screws if you can find them.

I don't like sub box designs that require you to remove the woofer to remove the box. They are a PITA if you ever have to do any work back there and only lead to failures of the box or the screw driver through the surround.

Edited May 21, 2015 by Bawshogg