Speaker enclosures

My direct drive Malibu has speakers cut into the dash and in the rear along the side pockets. Typical direct drive installation for years. I also have a sub under the dash at the drivers fee. The speakers really have no enclosure and are fairly open to air. My system sounds good and for the most part the only time it is really turned up is while running the boat. Otherwise I prefer to keep the volume down where you can speak over the system. Regardless, is there something I should do to increase the performance in these locations.

Can you give us an idea to the equipment you have in place now? What amps (model, watts, # of channels), what speakers, sub. What type of sub enclosure, ported, sealed, "bass reflex"? What head unit, is there an EQ or preamp of any kind? Do you place CDs, MP3, iPod, etc...?

The more info you provide the better feedback we can give you.

X2 for more info.. pics are always a plus as well!

Receiver Alpine CDA9886M
Amp Alpine PDX 4.1M 100W per channel
Sub is one of those packaged units Bazooka MBTA 8100 with built in amp
Total of 4 Polk 6" 2 way speakers but I don't know which model.
No EQ or preamp.

There are no tower speakers only the two in the dash and the two on the sides near the rear seat. I play an iPod. I've typically tried to keep it simple...and dry. I relocated the head unit from the Malibu under armrest location to the glove box and installed the Alpine wireless remote on my dash. My thought was the speakers open to air would be the weak link but I can see by the questions you guys know where to take me. I'll look for some pictures.

Its not my boat but he pictures are accurate.

One on the dash behind the glove box.
One on each side at the rear.
One in front on the drivers instrument pod, The sub is at the drivers toes pointed toward the starboard hull.

Tim,
You are fine on the fullrange coaxials and the Alpine 4-channel amplifier driving them. Thats definitely not your weak link. And, the Alpine HU is great.
The powered Bazooka sub uses two BTL amplifiers driving a dual voice coil 8-inch sub. These 12 volt chip amplifiers don't have a switching power supply so they are limited to the same type of power that you would get from two channels of a typical source unit. Many of those are rated at 4 X 50 watts but we know that is a VERY liberal rating. So your subwoofer is always going to struggle trying to keep pace with the highpass channels and remain sounding clean and tight. Its just not enough clean power to drive a subwoofer in an open field environment with lots of noise competition.
At some point I would upgrade to an enclosed 10-inch subwoofer with an external amplifier.
Past that its going to be down to the installation execution and quality of system tuning in determining the performance of your system.

David
Earmark Marine

Thanks David. FYI, the better parts of the system have come from you guys.

I thought I should do something to create a "chamber" on the rear/backside of the speakers because except for the one at the passenger seat because they are "open" air.

Also, I have a separate control for the sub which is very convenient but I find myself messing with it a lot, depending on speed and music. Would it be more "stable" if I ran the volume control of the sub though the head unit as well.

If you would like more output you will need to run more power to the in boats and depending on the polk models you have, you may want to upgrade for better SQ.

It's always good to run more power then run at the lower end of the speaker's capability, we use polk speakers often and found that if tuned properly you can throw 800 watts at a set of 4 and they will sing, the MM polks will have a bit cleaner sound then the db series. If you just want more output and cleaner sound at higher volumes I would throw an 600 to 800 watt amp at them, # of channels depends on whether you are running the db or the MMs because the ohm load on them does differ from one model to the other.

I've got plenty of volume for my liking. I like to be able to BS with people in the boat and I do not think I'm over-driving my system while underway. I just want it to sound crisp.

I thought about adding tower speakers but not so much for the rider but for listening while taking a break out behind the boat without pounding on those relaxing in the boat.

i have 6 polk db's with a 5 channel 840w amp running them and they are real loud for being an inexpensive speaker. although i have heard the lifespan of them isn't that great. like david said, you are probably going to want to upgrade the sub and sub amp for optimal sound at higher levels. you also talked about adding tower speakers, if you do, you will want to add an EQ. the ws420 is a top pick on WW. with that EQ you will be able to run your tower speakers as loud as you want, while keeping your inboats low like you said able to speak over them.

Nobody really answered my original question but I do appreciate all the input. Maybe it's been ignored because its not an issue but are my speakers all right in their open air condition or do they need a box?

If your asking whether or not you should add an enclosure of some type behind the in boat speakers, I would say no. Would not get you much different of a result then your current setup.

Again this assumes that the tuning was done correct, if so then nothing we dramatically change your current performance.

Did that answer the question?

Tim,
I get this question alot and often the purpose of the isolation pods are misunderstood.
Your coaxials are a true 'infinite baffle' type so they are designed to correctly work in expansive car doors, trunks, coaming cavities and helm consoles. Placing your coaxials in a small isolation pod/enclosure will raise the effective resonance and midbass cut-off point. Using these pods can actually be to your advantage if you have a legit acoustic isolation problem to overcome. Issues might include a free-air woofer in very close proximity to and sharing a compartment with a free-air sub. Or, a speaker that is mounted at the edge of an open coaming pocket and therefore has little to no front to rear isolation and no back pressure to help damp the speaker. Or, a speaker that shares a small and confined compartment with an enclosed woofer that is extremely powerful and seriously modulates the smaller highpass free-air speaker. I don't think any of these applications apply to either your boat or the scale of your system.
Adding the pods in this case would be counter-productive. There isn't anything that needs fixing. Or, the problem is so mild that the effect of the fix is worse than the current condition.

David
Earmark Marine

Thanks all. Great advise and insight!

The system does sound good and the point made on the sub is probably correct because I can tell that the sub is the first thing to hit its acoustical limit.