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Jeff W
04-12-2010, 09:21 PM
I will have a single 12" sub in a sealed enclosure - my question is shall I point the sub towards the driver or towards the front of the boat? I've heard both arguments.

Thoughts?

stretch55
04-12-2010, 09:27 PM
Mine is toword the driver and it can get pretty intense. I have never heard one facing opposite. Be curious to see what the out come of this question is though.

ian ashton
04-12-2010, 10:38 PM
I have mine facing the rear of the boat (pointed towards the driver) and have had great sound quality; I do also have a second sub behind the observer seat though also.

you da man
04-12-2010, 10:41 PM
My JL Audio sub is in an enclosure and fires towards the driver and it's loud.

mmandley
04-12-2010, 11:48 PM
I did a lot of testing of this theory also. I fired the sub up into the dash and tried it firing down into the floor.

I personally didn't notice much difference. Facing up, and facing the floor the only difference was some songs you could feel the sub a little better as in the vibrations. Sound quality was the same in my mind.

I had the new box designed to fire forwards more for looks then anything. Remember a sub has to move air. When its in a sealed box, it still needs to move air off the woofer cone, if the air space is to small the sub will be less efficient. Firing into the drivers seat or forward gives you the bling factor, also you get that rush of air from it, and you can starve it for air to move.

Just my thoughts.

Jeff W
04-13-2010, 10:50 AM
Thanks guys - I'll face it towards me as I've seen most done. The only reason I ask is because I've heard a few guys saying when you face it forward - the properties are similar to a bandpass box when it fires into the front seating area.

NCSUmoomba
04-13-2010, 11:39 AM
I vote 100% for facing it towards the bow. In my mind, it is similar to putting subs in the trunk of a car. If they fire backwards toward the trunk lid, they tend to sound better. Plus I like the fact that it is hidden from view and protected from damage.

Jeff W
04-13-2010, 11:55 AM
I vote 100% for facing it towards the bow. In my mind, it is similar to putting subs in the trunk of a car. If they fire backwards toward the trunk lid, they tend to sound better. Plus I like the fact that it is hidden from view and protected from damage.

the plot thickens. I can see both arguments. Let's discuss further.

kaneboats
04-13-2010, 12:04 PM
Try it both ways and see what you like better. Make sure you do it on the water. It will sound different in the garage, out of the garage and in the water.

morgan040
04-13-2010, 12:19 PM
I put it in facing bow, driver, and the sides, and up. It no doubt sounds loudest and cleanest facing the bow of the boat!!!! It doesnt look as cool but hey its a sub, its for sound not looks right. I didnt have enough room to have it face the bow so mine faces to the side which is still much better than facing the driver.

Bass needs to bounce off of something to sound good!!!

http://img.photobucket.com/albums/v383/morgan040/IMG00014-20100409-1432.jpg

csmsk
04-13-2010, 01:40 PM
Damn, you guys... I would love to have my sub enclosed better than just the stock location, but there's NO WAY I could give up that much foot/knee space. I'm 6'4" and need all the room I can get. Maybe someday I'll rip out or modify the existing bulkhead, but for now I guess my wimpy bass will just have to do.

Brianinpdx
04-13-2010, 05:03 PM
A few observations for everyone.

In my experience the question becomes one of more practical application versus any clear hands down winner of a forward/ rear/up/down firing sealed enclosure. The real question people should be asking is, "can I get a bass reflex box in my boat helm location and not give up to much space."

Sealed enclosures should typically take up a lot less space.
Bass Reflex / Ported / slot vented will take up more space depending on the target volume and tuning.

With all this in mind, why then would anyone want to knowingly give up more space? Good question right? Answer is: A bass reflex enclosure uses the sound from the rear side of the diaphragm to increase the efficiency of the system at low frequencies as compared to a typical closed box loudspeaker or an infinite baffle mounting. This is what creates SPL. It's the Sound Pressure Level that we enjoy as bass. From a musical point of view, adding a sub to your setup will provide almost 2 octaves of sound where your cabin speakers stop. It also allows you to target your cabin speakers with more specific frequencies by running their amplifier in HP mode.

Remember, the goal is to maximize sound pressure level. If we keep our eyes on that goal, the rest is easy.

Jeff - If your going sealed. I'd try to dial down the enclosure to the smallest possible size for the given woofer. The bandpass comment is people telling you things they don't fully understand.

NCSU - Putting subs in the rear of a trunk and bouncing the sound off the rear hatchback glass gives you "cabin effect". I've seen some of this done in the helm area by firing or porting up into the helm cavity.

Kane - Your comments are spot on. He should try things for himself and see the what happens. I put Mandley through a similar process and you all saw his comments. I'd be surprised if Jeff heard any difference....

Morgan - do you have a 15" woofer in that enclosure? thats huge man!


Cheers guys,

-Brian
Exile Audio

morgan040
04-13-2010, 05:12 PM
I just have a 12" Memphis Mojo but it requires a 3.5 cubic foot box. Thats why its so big.

Brianinpdx
04-13-2010, 05:50 PM
Morgan - that my friend is one giant box. I'm sure it hits nice and low but in terms of being practical, its pretty ginormous (is that a word?) for a helm. Hell you got no space! But you do have tunes! lol

Check out the enclosure we did for Mandleys ride. It's half that size and a fairly similar woofer to your mojo. He only lost 5 inches of foot space.

-Brian

ian ashton
04-13-2010, 06:07 PM
Where did you get that hose to extend the heater vent?! I need some, and can't find it anywhere!!!

byronkoz
04-13-2010, 06:37 PM
I was told by Kicker my sub would perform best firing down. Problem was if I did a down firing box id loose cubic feet and I thought that was more important so I built a standard box, sub facing out.

Razzman
04-14-2010, 10:29 AM
Where did you get that hose to extend the heater vent?! I need some, and can't find it anywhere!!!

Ian if i'm not mistaken that's dryer vent hose you can get at any home improvement center.

ian ashton
04-14-2010, 11:30 AM
Thats what I thought too; I'll have to re-look. I couldn't find it at Home Depot

morgan040
04-14-2010, 01:38 PM
Ian if i'm not mistaken that's dryer vent hose you can get at any home improvement center.

Yes, that is correct. My local boat shop had it for pretty cheap, I just saw it there one day. It was like 5 bucks for all that.

morgan040
04-14-2010, 01:42 PM
Morgan - that my friend is one giant box. I'm sure it hits nice and low but in terms of being practical, its pretty ginormous (is that a word?) for a helm. Hell you got no space! But you do have tunes! lol

Check out the enclosure we did for Mandleys ride. It's half that size and a fairly similar woofer to your mojo. He only lost 5 inches of foot space.

-Brian

I totally agree, but.... I have never put my legs under there even when there was room. I have my seat all the way back and the cushon up. I use the box as leverage to sit up higher. I still feel like I cant see over the bow and Im 6 feet tall. Maybe Im just not used to not seeing over the bow.

I tried to find a sub that could take 1000 watts rms at 2 ohms and that was the only one I could find at the time. Then when I went to install it I found out what size box it required....so I just delt with what I had. It sounds amazing but I totally agree, just a "little" big.

Brianinpdx
04-14-2010, 05:03 PM
Morgan - Makes sense! Hey all is good. As long as it works out right?

You where wise to look for a sub that you can throw a lot of power at. Makes a world of difference in that open air environment. hehe!

Turn up the "V"

-Brian

NCSUmoomba
04-15-2010, 12:17 PM
I have some pics of my sub box in the Mods section, the "Ruby Roo" post. I built a sealed 0.61 cubic foot box for my Infinity Perfect 10, and it sounds great. One guy I know has 4 12's (don't know what brand) mounted in the V drive compartments of his 'bu, and I swear my sub sounds better than his. Most people can't believe that I only have one SVC 10 running on 150W RMS. I maintain that it is a result of optimizing all the different variables to produce the best result. I will not win any sound off contests, but I like it, and I lost basically no foot space.

kaneboats
04-15-2010, 12:23 PM
I did a box something like yours on my O/B last year. I mounted the box high and forward on the port side wall behind the observer's seat, firing forward. It's as though the whole bow becomes a subwoofer. It didn't have much power going to it either, but it rocked!

EarmarkMarine
04-15-2010, 01:59 PM
There can be an audible difference based on how you orient your subwoofer. The following acoustical generalizations should help you predict how each approach will perform.

Forward-firing toward the bow or side-firing into the hull tends to create a little extra low frequency energy. Whether you think of it as a clumsy horn or bandpass, you are using the cavity and its interior boundaries as reinforcing planes. The function works best when the subenclosure occupies space within the cavity thereby reducing the cavity's displacement. The compliance of this air mass will store and release energy in a non-linear manner. The lowest registers benefit but the midbass transients suffer a little as some of that energy is consumed or filtered. So there is a slight loss in tonal construction that offsets the extra compression. If using a bass-reflex scheme its important that both the woofer and port radiate without obstruction from surfaces that are too close. Its also essential that both the woofer and port are either collectively directed into the cavity or outside the cavity and not directed into separeate environments. If you direct these two sources with one into the cavity and one into the open air, you will still see output benefits of a ported enclosure, but you'll definitely lose sound quality. Its important that you have a uniform phase response between the woofer and port. There is a difference between just 'ported' and 'tune-ported.'

Direct-radiating toward the driver and into the open cockpit will deliver slightly less compression comparatively. However, the transients, midbass attack and articulation are a little better in a direct-radiating scenario, particularly if your crossover frequency is set high enough. There's a lessor distinction in tonal characteristics if your crossover is set really low. Placing a woofer at the face or opening of a substantial under-helm cavity is somewhat counter-productive because the cavity acts as a bass trap. So having a tall enclosure or facade to provide more isolation from the cavity helps.

A free-air subwoofer in the floor hump will also benefit from an overhead facade that provides a partition from the helm cavity and also provides another reinforcing boundary.

Downfiring should be reserved for necessity only. This will undoubtedly shake the floor. But placing the woofer too close to the floor can change the 'Q' and serve to choke the output when you effectively reduce the radiating surface area. So follow the same precaustions you would with a forward or side-firing sub. Keep in mind that applications that work well in the enclosed cabin of a vehicle do not translate to an open-air environment. In a vehicle, after a certain amount of excurion and below a certain wavelength the cabin interior becomes an increasingly more rigid air mass. As a result the woofer couples very well and this effect can offset a multitude of inefficiencies. In a boat, on the other hand, a transducer has only a fraction of the leverage so don't make the task any more difficult for your subwoofer and sub amplifier.

The acoustic differences are not the only considerations in designing a Moomba subwoofer system. The under-helm conditions vary by model and year... How and where the cables enter/exit the top of the hump for example. Or, your personal tolerance for lost leg/footroom is a concern too. So woofer orientation is a predominant acoustic factor but certainly not the only one in the equation. There is no singular approach fits all prescriptions. Take it boat by boat.

David
Earmark Marine

c.rix
04-20-2010, 07:21 PM
Jeff I have 2 12's the driver side is firing toward the side of the hull and mane they pound I would recommend doing that also I had great results with it like that ! The box to fit that area gets creative though so be prepared to test fit a few hundrend times :)