92 Formula

iTrader: (2)

I have been away from car audio for at least 8 to ten years. Due to that, I am completely out of the loop on current 3rd Gen stuff and who makes stuff for them. I am looking for companies that make sub boxes for two 12's or two 10's that fits flush in the "trunk" and level to the "trunk deck" like many of you have (Blake, Burn 'EM, 1gta2c, 87tpi and Rexer). I want them flush to the deck, like the above members have theirs, because I want to be able to store my T-tops safely.

What reputable companies make good boxes like the above? If you have their web addresses please provide them, too.

BTW, I highly doubt I would have the time to build my own, otherwise I would be interested in that, too.

Thanks sincerely for the time and info you may provide.

antoine

i have a box with two 15 kicker comp vr`s that fit in the well from www.ryjocustoms.com

ScrapMaker

just go to ANY car audio store...

you can get 1 of 3 different boxes (that I have seen)...

1. dual 12" box, sits level with the rear deck, stops at the midway ledge in the well
2. dual 12" box, sits level with the rear deck, fills the entire well
3. dual 15" box, comes up to nearly the top of the rear plasic, fills the entire well, and comes out to nearly 4 inches from the back seat.

Captain C

Don't buy the Q-Logic. I loved the single Q-Logic sub box I had so I bought the dual box with the custom fit cover that looked so cool. As it turns out, I have the rear wiper and the inside of the deck lid is several inches lower than a car that doesn’t have the wiper. The inside of the deck lid would hit the top of the box and I couldn’t shut the lid. Also, the box was too shallow for my Alpine Type R 10” subwoofers. I ended up cutting holes in the bottom of the box and mounting a piece of 1”x12” maple (painted black like my interior) on the bottom and sealing it with silicone. I mounted the amplifier on the bottom side of the maple with a computer cooling fan to blow air across the amp. I had to buy some grills at, hac, cough, Radio Shack. Actually it turned out looking pretty nice...... Just hated paying so much for something that was supposed to be custom and then have to modify it so much. I could have bought a better box for half what I paid ($205) for that..

While on the subject of Q-Logic..... I also bought the custom kick panels at the same time. What a joke!!!! They aren’t close enough to the originals to even dream of using them and they are too shallow to mount my Boston Acoustic RM-6 6.5” speakers. They look to be too shallow to mount anything over a cheap brand of 4” speakers...... Another $115 down the drain. Looks like I have to fab’ something myself.....

No more mail order on "Custom" parts........

HamiltonAudio

have had the same luck with customers qlogic boxes, but NOT the kickpanels???!!! they are a great foundation for custom building something. I've seen them fit very nicely in 3rd gens (including my own)....if they're not deep enough, we can build onto them with mdf, bodyfiller, icing, 'glass, etc....get the fit/look you want, texture and spray (or cover in vinyl or carpet to taste).

as with anything custom, don't be surprised if you have to massage

bmoney

Jim85IROC

iTrader: (2)

I still build thirdgen boxes. If you're interrested in a quote, send me an email.
jim85iroc@yahoo.com

92 Formula

iTrader: (2)

Thanks Jim, I'll be contacting you soon.

For everybody else, the reason I am looking for reputable online sub box sellers is due to the fact I presently live in an EXTREMELY rural area...I cannot stress that enough. There is no local, or semi-local, shop in this area.

If anybody else has any further ideas please add it to this thread as it may help others who are in the same predicament as myself. Ideally the best thing is for me and others to build their own box, but I sincerely do not have the time.

I appreciate everyone's input in this thread. This is a great board and very well moderated.

Thanks again.

ScrapMaker

your best bet is to get jim to build it for you... or just drive to the nearest town and get one for under $100... I got mine for $75 because they sold me some speakers with it, and they are usually really desperate to get rid of these old things, because they don't fit in any other new cars...


if you find a 15 inch box they will give you a really good deal on it just to get rid of it even moreso, because almost nobody wants speakers that big.

Captain C

I figure that I'll need to get a spare set of kick panels from the salvage yard and cut/fiberglass the Q-Logic pieces to fit. I was hoping to get the front speakers installed before I take my 700 mile drive to Utah on Tuesday..... I need to talk to a friend, but it seems I remember him telling me what I needed to put in the fiberglass mixture to get colors...... If worse comes to worse, my interior's black and I have a can of spray paint for a temporary fix.

FyreLance

I had the guy from SubThump.com build mine for my fourth-gen. He does thirdgen boxes too. Very quality.

ScrapMaker

I bet he has a 4th gen sitting around to make it with, if he didn't have a 3rd gen around, I wonder how well it would fit?


also how much was that? its simply amazing!

FyreLance

It was like ~$300 since I had the logo embossed on there, it's like $275 or something without that. I also picked mine up.

ScrapMaker

*** damn that is expensive! I picked mine up for $75... for two 15's

FyreLance

Yeah it's expensive, but it is very quality. I had it built for the specific airspace I wanted for my sub, and he used very high quality MDF. Plus, the way the box is designed allows me to still store my t-tops back there (notice the notch in the top... the t-tops slide in there.)

CAMp3RO

Ryobi, Craftsman, Makita, etc

(had to be a smart @$$)

HamiltonAudio

I was unaware there were grades of MDF??? been in the business a long time, and have yet to see "high grade mdf"...

??

bmoney

stiers

iTrader: (1)

I would guess that when he said high-grade he meant that it was thicker and not flimsy.

HamiltonAudio

I guess so. in box construction, there are really minimum standards that go into a good box. Like bracing, sufficient size material, etc.

to say I spent extra (how much extra btw?) to get thicker mdf (from what, 5/8 to 3/4 or something) is another way of knowing the installer duped you, thats all....

bmoney

FyreLance

I never even said high-grade... lol... but yeah, stiers, you're right. It's just nice and thick and braced well.

HamiltonAudio

"and he used very high quality MDF." copy/paste directly....it doesn't matter, I was just curious as to what high-quality MDF was, as I'd never heard of such a thing.

bmoney

ScrapMaker

I only use 1" HDF for my boxes...

HamiltonAudio

even for an enclosure for a single 10" driver that will see 200 watts?

bmoney

ScrapMaker

the build quality is always a factor... instead of doing 1" hdf, I use 3/4 mdf, with cubic bracing along all sides... this even helps when you are screwing it all together, as well as help prevent leaks...

the whole point is, you want the speaker to vibrate, not the box, and the stronger the box is, the less that will happen... for example if you made one out of an oak tree or something, I forget what the strongest wood was, but all that matters is that the wood that the box is constructed out of cannot vibrate... if you made a box with anything less than 3/4 mdf, I'd say it would be questionable how much quality/volume would be lost through excess vibrations... one way to fix that is to make the box ported though, you can pretty much make a good ported box out of crappy components if you know what you are doing, because they are less stressful (airpressure-wise)...

I also love using that sealing foam stuff, and go over all my already-sealed edges, just in case... then if you go sealed... time for some poly-fil

HamiltonAudio

there is a reason we don't use wood with grain in the enclosure business. grains have "voids" between them, which allows small amounts of air to leak. all these little leaks add up to a change in alignment and ****ty sound.

you're right, you want the drivers to expend all their energy vibrating the air, NOT the enclosure. but I strongly disagree with you about the ported box. below port tuning frequency, very little "air" is coming out of the port. AT port tuning frequency, things come to a standstill. its only past port tuning frequency when the box begins to unload. thus, there can be just as much pressure inside a vented box than a sealed one. which is why its equally important to have a vented box as sealed up and airtight as a sealed box.

polyfil is a bit of a misnomer as well. really its only purpose is to "fool" the driver into seeing a slightly larger box because the rear wave is dampened. there are debates on just how much, but concensus seems to be about 8-10%. In terms of adding to sound quality, I've done subjective tests for myself, and have found little or no difference with/without polyfil. its up to the user I guess!

in terms of sealing the enclosure, there is a SUPER easy way to make sure all your seams are airtight. Go to Walmart and buy yourself a can of rubberized undercoating! coulnd't be any easier to use, and the product actually gets sucked up by the mdf to a point. when you get good with it, you can spray it such that a nice bead of undercoat settles on all the seams. I've found no better way to do it....quick, cheap, easy, and drys fast.

fyi, while we're on the topic. if you use silicone caulk to seal the box (lots do), let the 'cone cure completely before installing the drivers. the noxious fumes that 'cone gives off while curing have very damaging properties to many of the materials drivers are made out of. it can weaken surrounds, spiders, etc....let it dry!!

bmoney

FyreLance

I usually just pour a thin coat of fiberglass resin in the box and let it dry to seal it.

HamiltonAudio

that would work really well too. but I guess the question comes down to cost. one can of undercoating is 2.96 at walmart, and is enuf to seal several boxes. resin on the other hand?

great ideas tho!!

bmoney

ScrapMaker

That is very interesting, can you explain that a bit more about the pressures in a ported box? I really think that it would be much less... considering that when you push on a driver in a sealed box, it pushes back quite strongly... but when you push on the driver of a ported enclosure, the speaker only comes back because of the magnet... but I could be completely wrong, I would just think that a ported box would have much less pressure on the inside....

so the air travels into the port tube, and basically just moves in and out with the woofer, but not actually much air escapes? is that what you are saying?

I know on every other ported enclosure I have seen, it sends high-velocity air, pulsating on the inward "hitting" of the driver... but the extent of the ported enclosures I've worked with are computer subwoofers, and home audio woofers around 8" (not subs)

I'd love to hear about this, because I am thinking of making my sealed box into a ported one, and if it's just gonna sound like crap even with the correct porting, then I would not do it... the knowledge would be helpful though...

thanks,

Steve

HamiltonAudio

everything is relative. remember I told you that past port tuning frequency, the sub begins to "unload" and move freely? when the sub is not powered, its resting at "dc" which is effectively 0 hz. this is MUCH past port tuning, isn't it??

above port tuning frequency, the air WITHIN the port vibrates more than it rushes out. its this vibrating that acts as another driver and gives the vented box its advantage in efficiency. do a test to prove my thinking: a given ported box tuned to 30 hz. play a test disc with raw frequencies on it, and play say 60 hz. now put ur hand over the port. I GUARANTEE not much if anything is coming out of there now play the 60 hz frequency and notice how the subs are almost standing still!!

ports (beng tubes or slots) exhibit "resistance" to flowing air. Much like a too-small garden hose restricts large water movement. (this is called frictional loss). We are able to calculate that a port of x dimension in a box of y volume will exhibit a certain frictional loss and "tune" the enclosure to a specific frequency. Think of that garden hose and its restriction - in many cases, you don't want the full flow, so the restriction is helpful. this is how a port works for us!

there is serious science behind how all of this works. if you're truly interested in the fine points from the beginning, get a copy of Vance Dickasons "Loudspeaker Design Cookbook". It gives you the gory details from start to finish including the math if you'd like to handbomb it!!

later,
bmoney

ScrapMaker

you say (for example) that the 60hz the speakers will looks like they are still... does that mean its not gonna be playing any sound?

HamiltonAudio

yes and no. I'm saying if the box were tuned to 60 hz (which is WAY too high, btw), and you played a pure 60 hz frequency, the subs would appear to be almost standing still.

However, output at this frequency would be substantial. Its a weird law of physics, and doesn't make much sense does it. but its true! in an anechoic setting, output within one octave or so of tuning frequency is generally greatest....the point at which gain is most significant.

don't forget, each vehicle has a natural "gain", called transfer function (literally box-within-a-box syndrome). each car's "loud spot" is different based on shape, accoustics, etc. To truly take best advantage of an alignment, a shop would measure the cars accoustics with an RTA and plot the vehicles frequency response.

for smoothest response, you want to tune the enclosure (whatever the design) to be strongest where the cars "gain" is the weakest. so, if the GP chassis has big gain in the 70-100 hz range, you don't want your enclosures gain to be in the same place. if you do, you'll have wicked output in that range, but a somewhat weak response elsewhere. but if you tune the enclosure to be strong in the 30-70 hz range, you'll have great output from 30-100 hz (the box being strong 30-70, the car being strong from 70-100) clear as mud?

cash-money

ScrapMaker

what are our 3rd gens strong at? nothing?

HamiltonAudio

oh no! the 3rd gen "pit" actually has very potent gain. I don't remember the numbers I modelled my 82 Zee at (did it like 10 years ago but you can bet that just about anything, done right, will pound pretty nicely.

the trick with the 3rd gen is....keep the subs down in the pit, firing up. seems to be about the best.

bmoney

ScrapMaker

well to tell you the truth, the best deep bass I have gotten so far is when I had my subs facing away from me, in the well...

the current setup I have now where they reflect off of the hatch, you hear the high bass notes too much... and the bass I like is below all filters that I have heard... I want to muffle anything over about 40hz, because it seems to hurt my ears when it gets much higher....

also I don't know how your cars sound, but when you have the subs pointing up, they tend to make the hatch vibrate more... when they point towards the rear, you seem to get deeper bass...

I wonder how it would sound if you had the subs on the bottom of the box, and a rear-facing porthole? It's a shame we can't get very good ported enclosures in our cars... the smallest one I've seen specs for wants like 5cu ft per driver.

HamiltonAudio

its a matter of to each his own. I'm curious about your assertion of 40 hz and down. that is VERY deep bass. what program material are you listening to that has the majority of its output below this point?

also, whut subs are you seeing that want 5 cubes per chamber???!!! sounds like an spl tuned 15" sub to me! I'm tinkering right now with a ported design for a pair of Infinity Reference 10's, and its in the 1.1 cube per sub range. more than doable in the hatch of a 3rd gen. Recently did a vicious vented design for a pair of Pioneer SPL2000 12's, destined for the xcab of an s15 truck. the design called for maximum output, and still only 2 cubes per chamber....that truck is pulling high 140's on the new termlab

bmoney

ScrapMaker

well for the question on the 40hz thing... the reason I believe it is that low is because the lower I go on the crossover the better it sounds (to me), and it stops at 50hz on my deck, and the amp doesn't go that low either...

check out the specs on the Kicker CompVR 15's... the ported enclosure is like 5.5 cu. ft..... my PPI's are very close in the ported design from what I looked up.

to give an example... I still have not been able to re-create as "deep" bass as I once had with my old single 10" subwoofer in a truck-box wedge design.... it was sitting in the well facing away from the driver... that is by far the deepest low-volume bass I have ever made before in my car... granted it could not hit as hard as my 15's for obvious reasons... but now it sounds like the hatch is amplifying the 100hz+ naturally... in fact, to me, my system is about 5x better when I cover the woofers with my t-top storage bag.


if I made another box I would do like I said and either make dual rear-facing 15's, or with a port on the top as well...

Jim85IROC

iTrader: (2)

I just wanted to elaborate a bit on what Hamilton said.

I assume that you're familiar with the resonant frequency of the driver. This is the frequency at which the driver itself resonates. This can be seen on an impedance plot as a very high spike in impedance. This high resistance at that narrow frequency band results in less power being turned into sound energy because the amplifier sees an easier load. But... the driver is more efficient at that frequency because, well, it resonates freely there.

Anyway... with a ported box, you get a 2nd resonant frequency whose frequency is determined by the enclosure tuning frequency. Just like the mechanical resonance of the driver, this frequency will show up on a driver impedance plot, which in turn will cause the amp to produce much less power at that frequency (which is why the woofers don't move much). BUT... because this frequency is the port tuning frequency, you have a tremendous acoustical efficiency in the enclosure at that particular point. A well designed box will have the tuning frequency and enclosure size tuned to compliment the natural rolloff of the woofer and produce a smooth response to a much deeper frequency than a sealed box can do. Such are the joys of a ported box. But... if your ported box isn't designed just right, you'll have a mismatch between the efficiency at the tuning frequency and the natural rolloff, and wind up with a terrible frequency response. If you're tuning for SPL, or to avoid a specific frequency response problem associated with your particular car, this can be used to your advantage, but in the vast majority of situations, it just screws things up.

HamiltonAudio

the one thing you're not mentioning in your dissertation (very good, btw) is the effect of natural cabin gain on the design. I made note of this in my previous post.

Lets also note that not any driver will work well in a vented enclosure. There is a formula (the result being "efficiency bandwidth product") helps us determine the suitability of a driver for a vented design. for the formula and how it works, read up in the Loudspeaker Design Cookbook If we try and use a driver that was determined NOT suitable in a vented box (in a vented box), we'll have terrible results.

The only other downfall I see with a vented design is the low end "danger". about 2 octaves below tuning frequency, the subwoofers have unloaded. this means the air within the port is no longer vibrating but rushes out, essentially allowing the driver to play free-air. In a high power situation, this can lead to "flopping" and severe damage. Subsonic filters are your friend with vented designs.

great banter!!

bmoney

Chrome

I'd go with JIM85IROCS sub box. I bought one oh probably been 3 years ago and works and fits great! I have two fosgate 12" subs in it and it hits HARD, heh. So hard my wife will not allow me to take our 6 month old in it (even though I told her I wouldn't even turn them on... ) She doesn't like the idea of those massive speakers staring her in the face - guess I wouldn't either... LOL

Only problem with sub boxes made of MDF - THEY ARE HEAVY!!! Just make sure you take them out before you go to the track - you'll pick up a 1/10 in the quarter! hehe

ScrapMaker

what do you suppose is lighter than mdf that can build a quality box?

Jim85IROC

iTrader: (2)

Fiberglass.

ScrapMaker

everything I have ever heard, to make the box strong enough to sound right, the fiberglass becomes heavier due to the required number of layers... plus I thought a lot of people still used mdf on the inside, and fiberglass to make the enclosure look better from the outside.

Jim85IROC

iTrader: (2)

People usually use fiberglass to mold to the exact shape of an interior space. I know of almost nobody who just puts it over the wood for cosmetics.

Anyway, if it's a flat smooth piece of fiberglass, it probably will wind up weighing as much as wood by the time you get it thick enough, but the joy of materials like fiberglass is that they are much, much more rigid when they are irregular shapes. In those cases, you can get away with a thin, lightweight enclosure that fits perfectly into your car.

Ever wonder why floor pans are shaped the way they are instead of being flat? It's so that weak-assed tin can have some strength. It's the same way with fiberglass. A thin flat piece of fiberglass isn't too strong, but if it's shaped in a way that it has a lot of rounded contours, it becomes exceptionally strong.

ScrapMaker

interesting... I had never thought of that... how light do you think you could get away with in regards to the standard dual 12 box that goes down in the well?

the mdf one I used to have was about 50 lbs I think...

the dual 15 box I have now is close to 80lbs

ScrapMaker

I guess you could make the fiberglass box so no one could steal it maybe? that would be a great feature..

onebadwagon

good post guys,

<--learns something new everyday.

just because i hadn't seen it mentioned.

in a ported box, the idea behind the port, is to change the polarity of the rear sound waves of the sub, back into the same wave that is playing through the front of the sub.

for the above reason,there is an efficiency spike with each port, is because at the tuned frequency, the rear waves is in phase with the front.

the mass of air moving in the port should be looked at like cone displacement.

ScrapMaker

does anyone here have a ported box? and if so, whats it tuned for, and does it sound good at all the other frequencies too?

I like the way my sealed box tends to sound good for any kind of music... but I wonder if I could port it to suit my low-end needs... I really want a box thats set up for 30-50hz... although everything online says I need ~5cuft per driver for these ppi c2's...

can you make a good ported box that's smaller than the required size? I mean, you see these "home" subwoofers sitting in their .5 cuft boxes, and they sound amazing... my friend had a 10" home box about twice the size of a standard computer subwoofer...

that's another one, how does a computer sub sound as good as it does? a 6" sub surely wants more than .25 cuft of space!

onebadwagon

post up the thiele-small specs, and you can figure out exactly what you can do with the subs.

with 15's i would tune pretty low, 25-27hz, most likely.

ScrapMaker

does that mean it would not sound very good at other frequencies? A sealed box seems to have a very wide range of frequencies....

onebadwagon

yes, absolutely, generally the tuning frequency will be approximately the lowest the box will play without unloading the driver and causing a problem.

but yes, there will be a definite gain at the tuning frequency, while still having a good sound above that frequency.



adam

ScrapMaker

http://www.sv-art.ru/eng/brands/precision.shtml

I have the pc15-c2...

so I would think that I would go with... I don't have any paper or pencil, but about 19hz, 6-8 cuft per driver... unless I'm just looking at it all wrong...