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"car subs" "HT" subs there is no such thing. Just the parameters are more for one environment or the other.
 

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Discussion Starter #3
Tell me more about this.

What parameters should I look for in a sub (if I was to have one built for me) that does not require the cabin of a vehicle to perform proprely (if car subs do require this cabin to function properly because I have noticed some guys putting subs on the backseat & it just does not sound as good as it should).
 

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The home subs are usually different.
Home subs are 8 or 16 Ohm. Indoors for the same SPL level you don't have to have a lot of watts. The home speakers are more sensitive(more than 90dB) but less chargeable.
The car subs are not so sensitive (90 dB or less) but can handle more watts.
In home are the walls fix, and you don't see that the speaker cone moves, but there is compression and sounds. That isn't work in cars. The car speaker must have more X-Max (sometimes 1" ore more) to do compression.
 

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Lot of different factors here. Outdoor or large venue often use big horns, they direct the sound making it louder. They also have low xmax like about all pro audio, and often don't go real low because it is hard to do in a large space. Lot of pro audio stops around 40Hz. In a car you have no room for a horn or a huge sub driver, so you go for more excursion. You don't have to tune really low because cabin gain makes it go lower. You only need to fill the car with sound and bass turns into 'compression' sound, you are compressing the entire cabin with bass waves/pressure while outside you could never do that. For HT you need to tune lower because you don't have cabin gain, also you might want to hear the effects sounds in movies that can be lower than typical music. Home and pro tend to be limited by mains power, while in a car you can go higher in power if you want to go to the trouble. They are tailored to that. A pro speaker will be very efficient and not need as much power to make big dB (horns, large drivers, etc) that also helps it be more durable for daily use...but they don't fit in a car or even most homes.

For an outside sub you would tune a little lower for use without cabin gain, and you need a lot of output depending on what you are trying to do. I would say similar to tuning for a stereo in a large room. Vented would be more efficient and a larger sub(s) would be better and will take less power at well. On the other hand lot of SQ people here tune ~30Hz or just under, that would not be bad for outside use anyway. The lower you tune the less dB you will get, but you have to get low enough to gain the SQ you are looking for. A lot of outside/large room stuff does not go real low because going loud is more important. If you have more room it is easier, I mean you can fill a wall in a house with IB subs and get some output or make a huge ported box. You really need larger of anything when you try to get lower frequency output.
 

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Discussion Starter #6
I dont really need low, loud is the objective (approx 40hz & up) & the listening point is outside of the vehicle (anywher between 20 - 50 feet away).
Space shouldnt really be an issue since most likely its a big vehicle I will be using it in (looking to change rides in a few years). I am considering a pair of horns BUT the fact that it will not be used like the traditional car audio subwoofer is the reason why I am looking at this.
I am considering getting something custom built from david at psi to meet my needs (should be 4, 2 or 1 ohm to be used with car audio amplifiers).

Its sort of different how we do it here in this country, competitors line up, basically go at it & the loudest wins. The winner is chosen by ear not by the meter (like in bass boxing).
I have been observing many of them have started removing the backseat & building enclosures to fill the void to house subs. There goes the use of the cabin because basically all you have is the front half of the car's cabin remaining & the 4 doors are wide open throughout the competition.
I have been meaning to get into it one of these days hence the reason why I am looking at getting a sub for this specific application. Correct me if I am wrong but car audio subs wont work here & HT subs are too high of an impedance to match car amplifiers.
The use of a horn may very well be plausible because I will have a lot of space to play with in the van or if I so happen to buy a car to be used solely for this purpose the by all means, i'm going all out! :cool:
 

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I dont really need low, loud is the objective (approx 40hz & up) & the listening point is outside of the vehicle (anywher between 20 - 50 feet away).
Space shouldnt really be an issue since most likely its a big vehicle I will be using it in (looking to change rides in a few years). I am considering a pair of horns BUT the fact that it will not be used like the traditional car audio subwoofer is the reason why I am looking at this.
I am considering getting something custom built from david at psi to meet my needs (should be 4, 2 or 1 ohm to be used with car audio amplifiers).

Its sort of different how we do it here in this country, competitors line up, basically go at it & the loudest wins. The winner is chosen by ear not by the meter (like in bass boxing).
I have been observing many of them have started removing the backseat & building enclosures to fill the void to house subs. There goes the use of the cabin because basically all you have is the front half of the car's cabin remaining & the 4 doors are wide open throughout the competition.
I have been meaning to get into it one of these days hence the reason why I am looking at getting a sub for this specific application. Correct me if I am wrong but car audio subs wont work here & HT subs are too high of an impedance to match car amplifiers.
The use of a horn may very well be plausible because I will have a lot of space to play with in the van or if I so happen to buy a car to be used solely for this purpose the by all means, i'm going all out! :cool:

Where are you located and what brands do you have available to you?
 

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The horn does a couple things for you, one it directs the sound in a direction. That is not always a big deal with bass because it is omnidirectional anyway (and someone into pro audio can tell you what difference that makes at what frequency). But all your sound in one direction makes it loud when you are in front of it. It also loads the driver, so you need a totally different sub for that. The sub will not move much depending on how it is designed, or not as much as in a normal box. Think of it like a band pass port at many frequencies instead of at one like a vented box.

Likely they are going larger because they make a more efficient setup with larger subs and boxes, you can move more air with less power. The higher frequency you go the less air you have to move that is why SPL is ~50Hz and a single sub can do well there. At 30Hz a single sub just can't move the air, well say a 12" sub anyway, to make huge dB. So yes you need to know what frequency you need to cover, if you tune lower you will lose output.

The impedance is a matter of your amps and how you need to wire them, it is not much of a factor otherwise. It is easier to take 12v in a car and run lower impedance speakers and that is why cars use them, though today amps are much more capable. If you use a lot of subs there is no reason you could not parallel 8 ohm subs and have it work fine at 4/2/1 ohm or whatever, long as the sub you need was available in 8 ohm of course and it may not be.

I'd say start by figuring out how much room you have to work with, then you need to come up with a box that makes the most output for the frequency range you need to play. Not sure but you might get more information in the spl section bass race can't be that much different but I'm not up on spl stuff. Of course you need a way to power whatever amps you use. A larger similar sub will naturally have more spl than a smaller one. So you often end up with maybe quad 15/18s in an efficient enclosure. Maybe they run even more of them. It is a different game than small box used in a common car that is not efficient, unless you have 10,000w to power inefficient subs. When you don't have the power you need to make the sub more efficient and that is more of them in larger more efficient enclosures be it horns or vented boxes of some kind or whatever works.

There might be other factors such as what response 'sounds' louder even though it may not actually be louder on a meter, if using ears only. Does how the sound comes out of the car matter, how can you make it louder where the people are, not have the doors block the sound, etc.
 

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Discussion Starter #10
Im located in Trinidad & Tobago (In the caribbean, Trinidad to be exact).

As to what availiable, there are quite a lot of brands but I dont think I can use a normal HT sub (or whatever it is really called) in the competition (rules, rules, rules). However there is no rule stating I cannot use a custom built subwoofer.

This is all in the planning stages for now btw.
 

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Today you can get all kinds of subs to do all kinds of different things. Some are nicer for specific applications, but you can use whatever works. The only issue with a car is mostly if it will be exposed to excessive moisture or sun many home speakers are not good with that.
 

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Is this one of those systems where very few if any drivers face the interior of the vehicle and all "judging" is completed outside the vehicle (where the drivers are pointed?)
 

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Speakers started off as a speaker with a paper cone, paper dustcap, and typically an accordian paper surround. This worked fine for low powered radios and television typical of the 1950's. As stereos evolved, manufacturers started using foam surrounds and woven cloth surounds to achieve greater excursion. more excursion: more air moved, greater spls. As excursion increased, cone rigidity became more important, leading manufacturers to use high pulp cones. Heavier cones required more powerful motor structures capable of handling more power. Unfortunately, the resulting assemblies were inefficient compared to the older, lighterweight speakers. Prosound (as in concerts and DJ systems) stuck with lightweight speakers and smaller amplifiers while home speakers generally became more advanced and somewhat less efficient. in the 80's and 90's as mobile stereo systems became more popular, the environmenal concerns of using mostly paper and cloth became obvious. Paper speakers fall apart when exposed to moisture, sunlight, and humidity. new designs came out with aluminum and poly cones and rubber surrounds. They lasted forever but were even heavier than their predecessors. Eventually manufacturers found that if they combined a very large motor structure with a very heavy sturdy cone, they could design speakers that would still perform well in very small enclosures and would stand up to the rigor of the mobile environment.
So the differences in mobile speakers from home speakers and from pro audio speakers has changed over the years, and there have certainly been crossovers in the process. The cerwin vega stroker, probably one of the most infamous subwoofers of all time, was evolved from a pro sound design, evident in its treated cloth accordian surround and its dual spiders (also seen on very high end pro sound applications). Modern mobile subwoofers are generally expected to accompany at least a 2 way system and as such reproduce only 120 hz and below. A typical 15" pro sound driver, conversely, is often expected to reproduce up to 2500 hz or higher when paired with a compression horn tweeter. As a result, the need for a lighter cone material with more controlled breakup characteristics dictates that different construction techniques be used. for a long time, home speakers and car speakers evolved somewhat divergently, but now that home audio has switched from massive tower speakers to the current trend of satellites with compact subs driven by powerful class D amplifiers, the current state of the art in home audio/home theater look very much like the current state of the air in car audio subwoofer designs.

Additionally, pro sound speaker assemblies, as mentioned previously, are often constructed with horns to better project the sound, even on massive 18" subwoofer assemblies (the portable earthquake by cerwin vega being the first that comes to mind). In a car, however, the body of the vehicle itself acts as a horn, loading the speaker and directing its output. Its very hard to predict how a horn type enclosure will perform when placed inside the closed confines of an automobile.
 

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Discussion Starter #17
So what sort of ts parameters should I look for if I was getting a sub specifically built for a horn loaded enclosure (since most likely the vehicles cabin will not be of any use to me as almost half of the cabin will be used to house the enclosure & the doors will be opened)?
 

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Discussion Starter #19
I shall dig into it in my spare time.

Last time someone decided to use a sub for midbass a new rule was made & the mid bass drivers were classified as bass drivers so he was bumped up to another class. With a custom built sub I doubt anyone can classify it so it stays as a sub....but built for a specific application.
 

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Trini looks like it knows how to party! I like your mobile Hi-Fi style, just roll up and rave. Respect. What kind of music do people play?

I'd like a system like that. I've always thought it strange that most booming car stereos were unable to reinforce the dance. I'd much prefer to just pop the doors and go home than to carry 200 pound double 18 PA subwoofer cabinets and load a truck that doesn't even have an AM/FM radio.

I've always thought of there as being 3 major categories of subwoofers, each with different qualities depending on the application, but I don't know if this is correct:

Home (including Studio monitors and Home theatre)
Car (SQ vs SPL vs shrug-it-was-cheap)
PA (long-throw Stadium & near-field Club)

I'm just now learning about Car Audio and so I'm also interested in knowing the ways in which it differs from high quality Pro Audio and why it does. Any info on the subject is appreciated. Great thread, don't think I quite understand yet, but thanks to everyone for posting.
 
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