what would u do??(install q's)

[traksta15 0]

ok...here's my dilemna: i have (2) 12" premier 2000spl's, running off a hifonics bx1500d ("1500"x1@1ohm) in a 90 camaro, and they're currently running in a sealed box, because it's just begining to get warm here in the okla. i have decided what i want to do (box wise) and they are as follows....

1. i want the box to sit on the flat part behind my back seats and under my hatch glass.....

2. i need AT LEAST 3.5 cubes for the 2 subs (total, 1.75 apiece)

3. i want at least 60^2 of port area....

4. i would like to retain my back seats<----u no what im sayin?

now here's where it sucks:

i can't get enough box volume, with that much port area (and it hangs over onto the back seat...

i could just put the box on my back seats (they fold down flat), but that wouldn't make use of my back glass, and it takes up my most used "trunk space"

so here's my options:

1. build a ported box for 1 2000spl, and put it on the flat part where i would like it to go, and just run my hifonics at 2 ohms...(thank goodness for overrated amps right??)<--j/p

i dont wanna sell or buy anymore car audio equipment for a while, and would like to go with ^^^that plan....does anyone know about how much power my hifonics puts out at 2 ohms???and would 1 2000spl handle the supposed 1000 hifonics watts ok??any help would be greatly appreciated, TIA.....

[Supa_c 1]

run them isobaric

[traksta15 0]

elaborate please???

[Supa_c 1]

n/m

stupid idea..lol

[traksta15 0]

how is it a stupid idea???

[Supa_c 1]

ever seen an isobaric setup ?

[traksta15 0]

no, i've heard of 'em, never seen 'em...arent' they really complicated to build??

[Acidburn 10]

nope, they are not that complicated to build

[traksta15 0]

well what makes them special??can u show me a pic??explanation??

[mrray13 30]

iso is alright for small spaces but isn't known for it's effiency.

anyway, why not build the box to drop down into the lil trunk? that way u can get the needed volume and keep ur backseats??

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[traksta15 0]

i tried to measure it out like that, and it's not that box friendly...(and i can't/don't really want to fiberglass)would 1 2000spl take the "1000" watts??

[mrray13 30]

a good quick read on isobaric enclosures

i have no clue as to if the pioneer can handle the power...i know this, the spl series of pioneer subs have won the extrreme deathmatch a few years running....

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[traksta15 0]

what is the "extreme deathmatch"?

[traksta15 0]

after reading that i don't think isobaric is what i need...i want it to be loud, but not take up that much space.....i was contemplating about a 1sub/1amp setup but went ahead and bought these 2 anyways....i think if i watched my gains, and what not i'd be allright...they say it puts out around

1300watts at 1ohm so what would it put out at 2 ohms???like 800?if thats true i think i'd be just fine......

[mrray13 30]

u play as loud as u can as long as u can basicly...u break, u lose..lol...

or something like that..lol

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

[traksta15 0]

^^lol, i dont wanna risk my subs though.....

[traksta15 0]

and doesn't a ported box lower ur power handling??or somethin like that??

[dave_Edwards 1]

Many people don't realize that, unless you have virtually unlimited resources, there are going to be trade offs when designing a system. If you want a system to produce a lot of SPL (but have limited power or number of speakers), you'll probably have to concentrate a lot of the acoustic energy within a small band of frequencies. This would allow you to generate the desired SPL and properly impress your friends. It would, however, leave you with a system that would have less than perfect frequency response and marginal performance at the low frequency end of the spectrum. You could design a system that would produce the desired SPL at all frequencies but it would require significantly more power and speakers than the aforementioned system with the narrow peak.

Manufacturers Recommendations:

Many manufacturers recommend an enclosure that's going to give you a peak like we mentioned earlier. This will give you good results for rap or other bass heavy music. If you listen to those types of music, this system may perform satisfactorily. If you listen to all types of music, you'd likely want an enclosure that would give a flatter response. To get a flatter response, you could increase the size of the enclosure but the overall response wouldn't be perfectly flat. To build a system that had a perfectly flat frequency response (generally desired by audiophiles), you'll have to take the vehicle's transfer function into account (this will be discussed later). When a manufacturer recommends a particular enclosure, you should ask yourself (or, better yet, the manufacturer) what the enclosure is optimized for.

Enclosure Types:

When laying out a system, you need to decide what type of enclosure to use. No enclosure is magic.

A sealed enclosure will be the smallest (for a given response shape) and will have good low frequency extension but may not have the best low frequency extension. If space is limited, this may be your best choice.

A ported enclosure will generally have a better low frequency extension for a given response shape (alignment) but would require a larger enclosure. If you made the enclosure as small as the sealed enclosure but ported it to gain the low frequency response, the output would deviate from the desired flat response.

A bandpass enclosure can sound good and give you a flat response but most of the generic bandpass enclosures are not designed for a flat response. They are designed to impress you in the stores. This means that they are built to produce a large peak at some frequency near 60hz. These enclosures will work well with something like rap music but generally won't sound good with other types of music. If you use a bandpass enclosure, it should be designed specifically for your speakers.

a Free Air baffle,these are great for applications where trunk space is at a minimum and usually the easiest and least expensive way to add a subwoofer to most sedans. Not having to construct a box is an advantage, but many vehicles will require a new rear deck panel and/or vent to be constructed to accomodate even smaller woofers. These custom vents and panels could cost as much or more than a prefabricated or custom box.

Infinite baffle set-ups require a woofer with a beefier suspension for high power handling and one with better cone damping. This set-up will be less efficient in reproducing the lowest frequencies as compared to other second order or higher enclosures.

In any free air application, the back seat and surrounding panels should be removed to seal any possible areas where energy could be lost. It is crucial to separate (seal) the back wave of the loudspeaker (woofer) from the front wave of the loudspeaker. If not, bass cancellation will occur. This is also a good time to rid and deaden the trunk and surrounding areas of any unwanted noises and rattles.

now for the most complex design, a Transmission Line (TL) is not like any of these other enclosure designs. The Transmission line is an old design, but as it turns out, is almost a perfect system. For example, the Bose Wave Radio uses a TL enclosure to produce its award winning sound. As the name implies, a transmission line is a long tube that expends from the back of the loudspeaker. By tapering the line, there is NO possible way in which sound can reflect back and forth and therefore standing waves and resonances common to standard speaker enclosures are eliminated. By eliminating back-wave reflections, the driver is also protected from having the back-wave re-radiate through the diaphragm, causing distortion and diaphragm breakup. The purpose of the transmission line is to eliminate the phase cancellation that would occur if the driver was in free air. Because of the length of the line, there is not enough time for air to travel through the line and cancel the front-wave. The magic of the system is what happens to the back-wave. The length of the line creates a tuned chamber much like an open ended pipe from a pipe organ. This causes a phase shift depending on the frequency and the length of the line. Through proper design, this causes the wave from the end of the TL to reinforce the front-wave at the frequencies where the front-wave begins to decrease due to increased air resistance at lower frequencies. Also, the tuned aspect of the TL strongly effects the fundamental resonance of the loudspeaker. It causes a very heavy dampening effect, which also helps to eliminate the overshoot and undershoot of the massive bass driver diaphragm. But this dampening is unlike the air spring of a sealed box and the diaphragm does not have to fight for motion. As a result, the efficiency is better than bass-reflex enclosures, the accuracy is better than acoustic suspension, and the frequency response and linearity is better than all systems.

The line length is usually tuned to be 1/4 of the fundamental resonance of the driver loudspeaker. The TL can be folded, or in other words curved. If stuffed properly with damping material such as wool, the actual length can be decreased due to the resistive effect of the material on the air. The construction and design of a TL bass system may be more difficult, but the result is a dynamic driver than can truly complement an electrostatic loudspeaker.

If you're building your first system, I'd recommend a sealed enclosure. It is the simplest enclosure and will be the easiest to get right. A sealed enclosure only needs to be the right size and well sealed.

As you already know, for speakers (especially woofers) to work properly, they must be in the proper size enclosure. The manufacturer can give you the required enclosure volume but can't give the exact dimensions of an enclosure that will work in all vehicles. So that you can build an enclosure of the proper size for your vehicle.

Magic number:

OK... It's not magic but the number is 1728. If you forget it, just remember that the number is 12 inches * 12 inches * 12 inches. 12*12*12=1728.

Square or Rectangular Enclosures:

These boxes are the easiest to calculate the internal volume. You simply measure the height, width and depth (in inches), multiply them together and then divide that number by 1728. If the box has internal measurements of 6" high*18" wide*12" deep then the volume of the box is 1296/1728=.75 ft^3.

Triangular boxes:

The first type of triangular box has a right angle which will make the calculations a little easier. For a right triangle, you simply multiply the height by the depth by 1/2 of the base.

Things to build your enlcosure with

MDF

Medium Density Fiberboard is a compressed type of 'wood product' It is similar to particle board but is much 'friendlier' to work with than is particle board. The wood cuts with less dust and leaves a good clean cut as is seen below. It also resists chipping when screwing close to the edge. You should still pre drill the screw holes when assembling a box with drywall screws because the wood will split if a screw is driven into the end of the board. Many people (myself included) use a pneumatic stapler and a good quality wood glue to assemble boxes. Some people use liquid nails type adhesives to seal the joints but the solvents in construction adhesives can soften the adhesives used on some speakers (which could lead to premature speaker failure if the speakers are installed before the adhesive has dried completely). You should also realize that the fumes are flammable (and may be explosive when contained). If you have a loose speaker connection on the speaker terminals, you may have a fire/explosion hazard if the speakers are played before the solvent has fully evaporated. Silicone adhesive has acetic acid which is released as the adhesive cures. This acid will corrode speaker baskets if the speakers are reinstalled before the silicone has completely cured. The best way to make sure the enclosure is sealed is to make good quality cuts. It will take less time to make good cuts than it will for the sealant to dry/cure (24 hours).

Sealing around speaker:

If the speaker has no gasket and the speaker box isn't covered in carpet or vinyl, You can use an open cell foam weather stripping around the cutout in the baffle. The weather stripping should be about 3/8 to 1/2 inch wide and 1/2 inch thick.You need to make sure that the area around the cutout is clean and dry so that the weather stripping will stick. I recommend wiping it down with solvent and allowing it to dry before applying the weather stripping. If you REALLY want it to stick, apply a single coat of contact cement to the area around the hole and allow it to dry for 10 minutes or until it no longer sticks to your fingers when you touch it. When applying the weather stripping to the coated area, you get only ONE chance to lay it down in the right place. As soon as the weather stripping touches the contact cement, it's not coming back up.

Try them all, but remember that there is no MAGIC box that sounds the best, it is what are you goin to need from the enclosure/sub and what are you expecting.

hope this clears up sub enclosures.

[BASS OUTLAW 0]

1 sup ported will do...

i got the Pioneer version of ur Subs TS-W121SPL. in a 2 cuft powered with PRS-X340 @ 4 ohm (less than 700 w rms)

pics of the box is floating some where in the Show off section..

and am not sure if that sub will take the 1000w daily.. i think its too much...

[traksta15 0]

but aren't hifonics amps overrated @ everything except 1 ohm??at least thats what i've heard. I've also heard that even @ 1 ohm, they only do around 1300rms...my car has the stock alternator, and drops down to about 11 w/ my h/u on superbass,and with the volume at around 30/50....other than that it stays right around 13.5-14.4......would that help or hurt my choice of runnin it at 2 ohms ("1000" rms)

[traksta15 0]

i just hooked it up @ 2 ohms and it took it fine in my sealed prefab....(bout 1.5 per sub) with the gains 1/4 ways up....think it'll take it in a ported box???

[Supa_c 1]

Attenuate that gain, give the sub what it needs ( conservative )

[BASS OUTLAW 0]

how is the excursion ? watch out when playin the sub in ported (superbass.. can easily bottom out) if u r tunning high...

the wires from the terminals to the voice coil might get cut... that happened to me due to excursion.. it sucks when fixing it back

PS : if u got the Power ... why dont u put them in Small Sealed box ? less than recomended.. onlty if the sub cant take the excessive excursion..

[dave_Edwards 1]

with any ported enclosure the Xmax will be less---as is the power handling-----excurstion should have nothing to do with speaker wiring.

[BASS OUTLAW 0]

but while playin Lower bass tones( and tunning at 33.3hz or so.. .. excursion will increase.. and cone will lose control...