Sub distortion dilemma in boat

[customfab]

So I've spend the last 3 days installing a pretty nice audio system in my boat and I didn't go cheap on the installation. Running a Pioneer 8500MP deck, 2 pairs of Alpine Type R 6.5" component sets, 2 Alpine 12" Type R subs. Powering both the subs and component sets with Lanzar Opti amps that exceed the speakers & subs power ratings.

My subs are so far excessive in seems insane in a sealed box with ~1.5 cu ft per sub. I've got the gain turned about 75-85% of the way down. Problem is, my boat (fiberglass cigarette boat) is vibrating to hell. It really distorts the bass. It almost sounds like a terribly designed sub enclosure. The subs are in the engine comparment which has access to the entire inner shell of the boat (essentially there is about 6-8" of dead space surrounding & underneath the cockpit and hull to the exterior of the boat).

Any suggestions to tuning this thing correctly? Seems I would have been fine with a $80 10" sub.

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[Decipha 10+ year member]

try sound deadening underneath the box... may help

or you can always mount the box off the floor of the boat

 

[bri487 5,000+ posts]

fire your woofers into the sidewall of the boat, both woofers on the same side of the boat. the sidewall is the strongest wall in the boat, especially when it is in the water.

ps: i am a huge boat audio guy. wakeboarding boats are huge in my area, as is the stereos in them.

 

[rocky 59 5,000+ posts]

hmmmmmm i would try the sound deading as said above. also it is in the stock location with no extra box inside the stock local? i would try building a box around the stock mounting holes if thats the case and they put some foam egg crate around the walls of the dead space to absorb the sound

 

[customfab]

So I need some "cushion" underneath the box itself? It is currently bolted securely to some subflooring. This portion of the boat is extremely solid.

I do have the subs facing the engine and open end of the engine compartment. I guess I will try to turn the box around and add some sound deadening to the adjacent wall. Anything else?

 

[bri487 5,000+ posts]

So I need some "cushion" underneath the box itself? It is currently bolted securely to some subflooring. This portion of the boat is extremely solid. I do have the subs facing the engine and open end of the engine compartment. I guess I will try to turn the box around and add some sound deadening to the adjacent wall. Anything else?

boats are extremely sensitive to install. lots of cancellation. i have a single 12" in my boat now that was louder than two 12"s with twice the power of the same brand.

 

[DFW40 10+ year member]

make sure the subs are firing out to the open or create and channel for the sound waves to go out into the air and not into the cavity of the boat where they will get lost and cancel each other. Does that make sense?

 

[bri487 5,000+ posts]

make sure the subs are firing out to the open or create and channel for the sound waves to go out into the air and not into the cavity of the boat where they will get lost and cancel each other. Does that make sense?

unless its ported, i have never heard good results in a boat like that.

 

[Spooby 10+ year member]

On the install Moe Lester has been working on with the type Rs, they do not really seem to like playing into the open air too much. We have to put some baffles in front of them to help load the front of the drivers. the difference is night and day. without the pressure on the front they sound horribly distorted and almost as if they are out of phase.

 

[bri487 5,000+ posts]

On the install Moe Lester has been working on with the type Rs, they do not really seem to like playing into the open air too much. We have to put some baffles in front of them to help load the front of the drivers. the difference is night and day. without the pressure on the front they sound horribly distorted and almost as if they are out of phase.

when dealing with how sound works in a boat, forget everything you know about how sound works in cars.

 

[DFW40 10+ year member]

All I was saying that you cannot fire a sub into a big cavity or hull of a boat and hope that the sound makes it out....pictures would actually really help.

 

[customfab]

You are guys are going to laugh at this one but I figured that problem out fairly quickly the following day after the install. The bass boost on my amp was all the way maxed out resulting in bad frequency distortion thoughout the boat. I never knew it was maxed out or even turned up from mimimum. Now the subs sound very good. I can't crank the amp up nor set the bass on my head unit to be too far up but overall it sounds very good. You can certainly tell the system is very capable considering it is a boat.

 

[bri487 5,000+ posts]

You are guys are going to laugh at this one but I figured that problem out fairly quickly the following day after the install. The bass boost on my amp was all the way maxed out resulting in bad frequency distortion thoughout the boat. I never knew it was maxed out or even turned up from mimimum. Now the subs sound very good. I can't crank the amp up nor set the bass on my head unit to be too far up but overall it sounds very good. You can certainly tell the system is very capable considering it is a boat.

come out here and hear the couple zapco sponsored nautiques.