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Thread: Sub in driver footwell
04-14-2010, 05:03 PM #21
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"
04-15-2010, 12:17 PM #22
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.Brian Roberts
2001 Outback DD
04-15-2010, 12:23 PM #23
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!My Mom said I'm not allowed to get wet!
2000 Outback LS (sold)
04-15-2010, 01:59 PM #24
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.
04-20-2010, 07:21 PM #25
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 times2007 Outback V