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**pwrusr** · 12-18-2004, 01:19 AM

it sounds like a interesting plan man!
I think you will have to use dynomat at least on the rear deck to mimimize vibes from the subs pounding away at the rear deck.
I can't wait to hear some more info and PIX of this

free bump for you

**DRAGGEN** · 12-18-2004, 02:00 AM

well the free air idea is interesting..but as for that you use the trunk as an enclosure so..dynamat once again is gonna be your friend. your talking about subs: low frequencies means they move more air thus rattling in anything that has not had some sort of sound cancellation material applied to it. with the 8's dont expect rap bass to sound like you had 15's back there 10's is a better choice keeps the rms wattage down to a decent level and then you have to take into account your listening preferences do you have it loud enough so ppl stare at you when you drive by? or if your an old fella like me at a normal volume. Porting a couple of tens through the rear deck is a good possibillity from what i see in your post use a vented enclosure probably something band pass.

**ProblemChild211** · 12-18-2004, 02:34 PM

i dont really want to use free-air subs though... its gunna be too much hassle tryin to seal up the trunk...

i REALLY want to use regular subs (thinking of using the jl w6v2 10in OR an alpine type r or s) in a enclosure put up through the hole in the rear deck... i realize i will have to use dynamat on the deck... but will i have to use it anywhere else?? will the rear glass vibrate??

i listen to 90% rap... i dont like that rumbling,boomy unclear bass... i like that CLEAR, TIGHT heart-stopping thump... that good bass sh!t that you can feel in your heart that makes you feel like youve got a heart attack

.. i like clear nice bangs... i dont like that bass that drowns out the vocals... VERY CLEAR, TIGHT, HEART-STOPPING, STRONG,LOUD, THUMPS, daz mi sh!t...
BUT, i want to be able to turn it down..
what kinda subs do you recommend?.... im not looking to spend more than $400 on subs..

what are the top of the line free-air subs out there??

im looking for AT LEAST 150watts RMS each sub.

what can i expect with this setup (e.g. unclear tone, excessive rattling)??
is it gunna end up costing more than a trunk setup?

**chessboxer** · 12-18-2004, 02:43 PM

thats gonna take some custom work, and it was something i thought about at one point, but then when i saw all the metal id have to cut and al that, i just gave up the idea altogether. so the moral of the story is that you need to do this to show me up and make me realize that i shouldnt have been a quitter.
also, if your subs are pushing a shit ton of air, the glass might be an issue, as fat as breaking is concerned, especially with them hitting right there up to it. but i might be talking out of my ass there, so perhaps someone else can elaborate on that or tell me i dont know what im talking about.
good luck either way

**DRAGGEN** · 12-18-2004, 04:30 PM

i first always recommend Kicker (small enclosures) but JL is a good sub ill have to take some time and look up some of the parameters needed for the kicker or JL and maybe come up with a isobaric that can be suspended from the rear deck and yes the rear deck for sure is gonna have to have dynamat. Maybe some of the trunk such as the sides. Since they are just metal no factory material on them

The window no, off topic a little, i ran 1 12" solobaric kicker back when they were brand new on the market ,off of a Kicker XS 50 about 360 watts and didnt know i had a small crack in my windshield well when i did 2 runs of 145+ DBs the small crack spread right across my window. was kinda cool cuz i was the talk of the stereo comp how i had cracked my window..lol

ok back on let me check some stuff out and ill get back at ya.

**dwf137** · 12-19-2004, 08:13 PM

i suggust that you just suck it up and throw a sub in a small enclosure in the back, and deal with it. If you're going to be building an enclosure for the subs that's going to stick down from the rear deck and cause a visual disturbance in the trunk. Also, you're going to need a shitload of support in order to put any sub in the rear deck, which will be another visual disturbance. I've got 2 6 1/2's in my rear deck and when i put my stereo to about 1/2 volume, that rear deck rattles beyond what you can imagine. The trunk also helps to reverberate some of the sound from the sub if you face it towards the back of the trunk, and it will sound louder then it actually is..

my suggustion: get over your cosmetic kick, and go for function.

**Smokinspeeds** · 12-19-2004, 11:00 PM

forget the deck

Ok one thing you have to consider is that your rear trunk lid has two bars going under the deck. That's what keeps your trunk lid up when you open it. You can take em out but your trunk won't stay up unless you hold it. Then what does cosmetics matter? You won't ever be looking into your trunk for long like that. You'd also have to re-build your whole deck if you didn't want it to sound like trash. And being that close to your window it might make it pop off if you put some good subs in there lol. Distorted base sucks but that's half box and half how you set your audio. Tuning any setup is the most important thing with any system yet many ppl don't spend the time to get it right. Avoiding distorted bass is half just setting your head-unit and amp levels. You gotta spend some time with it. With any setup you can avoid distortion, although you might not get it as loud. Part of it also depends on the box. Bandpass boxes are good for clear bass and you might want one but they aren't going to necessarily be as loud as say a ported box. A sealed box would be really good cause there is no chance of the box over enhancing certain ranges since ported and bandpass boxes are normally tuned, but they don't enhance the sound in any way. Ported boxes done right can be clear, and they can be muffled. They can give you an extra 20 decibels of volume. The compromise is between extra volume and sound clarity. More volume=more distortion. I have a ported box that I built (my second) and I can get loud clear bass or even louder somewhat muffled bass. Part of that is because I don't have a good head unit and my amp is rather low in power. But heck ppl don't believe I'm running legacy 12"s with only 75 watts each rms from the amp. I only spent $225. You can hear me from half a mile away(literaly!) and I can't use my rear view mirror. I like getting a massage while ppl hear my stuff from a long ways away(although sometimes the headaches are anoying). If you are going to spend more on a better amp I'd say don't worry about it so much. More than half of the sound is in the tuning. I'd bet my system on it. For the best combination of box and speakers do a little homework. Some speakers like sealed boxes better than others, while others love bandpass. As a rule a reiforced sub cone is better for ported and bandpass boxes than paper cause the paper can't take as much decible boost without developing holes. What I want to upgrade to and I tell everyone is the best bang for the buck is power aucoustic comp subs. Look on the internet and you can get one twelve shippped for like $100-$120. 600 watts rms 1800 max. Put it in a sealed box and put some ear plugs in. Friend had ONE in his accord with a sony amp and had his bass on his head unit at like -5 and it was loud. You don't have to spend more than three hundred and it'll be more than you can handle while you are in the car. One guy even had his chevy nova fall apart completely from it. O.o Other ppl with two of them have taken them for DB tests and get around 148-9 every time. That's kickin!

**owequitit** · 12-20-2004, 02:38 AM

I am getting kind of old, and I was afraid of going deaf so I removed my subs awhile ago, but here are some thoughts.

1) You don't want the subs in the trunk for security reasons, but you are going to put them in the rear deck for every passer by to see? That sounds just as bad as putting stereo brand stickers all over your car. People will know what you are hiding. With them in the trunk they may or may not know...

2) The trunk springs will be a major issue, unless you remove them and somehow mount some gas struts to keep the trunk open (not a bad idea, and probably not that hard to accomplish).

3) The rear deck, although not terribly thick, is a structural component of the car, and you can expect adverse results if you remove all or most of it. You will definitely need dynomat on the deck, and probably still in the trunk in some parts as well. One of the advantages of our cars is that they have great acoustic properties as far as cars go. You can thank the relatively square angles and flat body panels for that. They will also vibrate with very little provocation. You can thank the lack of sound deadening and the fact that engineers had no clue what kinds of SPL's we would be pushing 20 or so years ago when they began designing our cars. Even if it sounds fairly solid at first, trust me, it will start to develop all sorts of rattles over time. I have a pair of Infinity Kappa 6x9's in my rear deck right now, and they really rattle the rear deck (no dynamat).

4) When you are adding 50-150 pounds of stereo equipment, I wouldn't really worry about the weight of the dynomat. It's not THAT heavy!

5) If you listen to mostly rap, and want crisp clear sound, you may want to consider 2 10" subs in a sealed enclosure. 10"s usually do pretty well in a ported or band pass box, but most 12"s lose a lot of clarity (8"s aren't really going to have the low frequency response that you crave). That would be a pretty good compromise between frequency response, dB's, and clarity.
I do know a 12" that just loves sealed enclosures, will blow your ear drums, and is clear enough to make you feel like you are at a concert when you play the fastest, hardest rock music you can think of. They only need 1 cubic foot per speaker if they are in a sealed enclosure as well. They are pricey though. I am speaking of Infinity Kappa Perfect's. Don't confuse them with the regular Kappa's because they are totally different. When I had them in my car, I had professionals that had been building stereo's for years and years tell me that they couldn't believe how good they sounded. The 10's will rock your socks too, and they need even less space in a sealed enclosure. They do require a lot of power though. Anymore, they are probably not the "loudest" but they are still the clearest that I have heard.

6)As far as sound quality for trunk mounted speakers goes, if you do it right, they will sound just fine because they use the whole trunk as a resonating chamber. You can also fold your seat down when no body is sitting in it, and that will help also.

Just some stuff to chew on. If you have any other questions, let me know and I will try to help.

**JDMCB3Si** · 12-20-2004, 01:04 PM

OK here are some clear ups on this.

1) NO WAY NO HOW will the rear window "pop" "crack" or "break" under th force of bass. That is virtually IMPOSSIBLE. This has been a laugh amongst all the installers I know and used to work with. the ONLY and I do mean ONLY way a windshield or window will break is if it has many cracks or is shattered already but still there.

2) Any way you go you will have to dynamat. Unless you get lucky like I did and nothing rattled. there is a spray in sound deadener made by rockford and i think stinger makes some also that you could use.

3) The rear deck free air idea is a good one yet you have a HIGHER chance of someone trying to or achieving to steal your system if you "FLAUNT" it. at least in the trunk they are hidden.

4) if yu want cosmetics to be in play why not go with something custom? If you have patience you could fiberglass an enclosure ANYWHERE in the trunk. I prefer the spare tire well. But how many times do you show off your trunk to people when they look at your car?

5) 8" subs are more of a midbass and unless you are using a solo baric (kicker) or one of the higher end high $$ SPL subs your not going to boom with them. You will be better off going with a single 10 or dual 10s by the way you described your tastes.

6) For security measures you could do like we did on my buddies system. We mad a false face to cover the stereo and make it look stock. Also made panels to go over the subs and amp rack. this makes it stealth and noone will know you have a system unless you show them.

there's your options as far as keeping low profile and being safe.

**ProblemChild211** · 12-20-2004, 08:17 PM

1. yea i realized my subs would be more vunerable to theft if i put it in my rear deck..

2.although i doubt that the subs can actually break the glass cuz of the rattle.... but have u ever been in your house and somebody was driving by with a loud bass stereo on?? and your window vibrated rite?? so this gives me reason to think that it CAN actually break the glass...

3. i bought the car at a killer deal at a police auction and there isnt any trunk springs anyway (neither any stereo- guess the car was stolen)...

4.i know its hard to notice but, have u ever REALLY tried and listened to a woofer in the trunk?? it sort of sounds like u listening to a system with ya hand covering the speaker (muffled sound)... a rear deck setup will elimminate this..
dont give me that bullsh!t about the (nasty) sound of moving air.... if that is true then are u telling me that sedan systems sound better than SUV or Hatchback systems??

5.By simply extending the whole port up through the rear deck, you can focus 100% of the acoustic energy into the cabin with zero energy wasted in the trunk!

6.Since the main goal is to get the loudest and cleanest bass in the cabin, let�s address the loss of volume issue. Taking the logical approach, we would be curious to know how the bass is heard in the listening cabin when the box is in the trunk. If the car was a hatchback, we would have the box in the listening area. But since it is in the trunk, what pathway does the bass energy take to get inside? Well, in cars with foam-backed seats, the sound can propagate right through the foam... Most of these cars have steel lined trunks. They pass even less bass. So, what pathway is left? Leaks! That�s it. So, the logical solution would be to increase the direct air coupling as much as possible. This would involve making some type of perforations in the rear deck, which would couple the trunk to the cabin.

7. using dynamat on rear deck, i will need ALOT less than if i use it in the trunk..

There isnt alot of research and info on the net on this subject, so i just wanted to see what ya got to say about this.

my #1 reason for wanting to do this is:

I LOVE WATCHING SUBS FIRE!

lol

soory for the book

**owequitit** · 12-21-2004, 12:36 AM

1) Having driven in many hatchbacks / SUV's, my Infinity Kappa's sounded better in my car with the seat up and no dynamat than anything costing even remotely close. Yes, you will need more power, that is a constant of physics. But the sound quality was better. No joke.

2) The key to breaking glass with sound, isn't really about SPL. It is more dependent upon resonant frequency. The glass generally has to vibrate fairly violently for a long period of time at its resonant frequency to break or crack due to sound. This is also true for every other material on the face of the planet. Reference "Galloping Gertie" (the first Tacoma Narrows Bridge) for a graphic look at this phenomenon. The glass rattles due to bass because it is hitting its resonant frequency, but it is not strong enough or long enough to break the glass. It could take minutes, at one constant frequency to do any damage at all. Not likely to happen with music, voice or any other sound you care to listen too.

3) I only had subs in my trunk for years and years. Never listened to them though...so I don't really know what they sound like in a trunk.

4)Physics Lesson: You can never focus 100% of the energy anywhere, because it is realistically impossible to have 100% efficiency.

5)The sound issue. In order to get the loudest cleanest bass in the cabin, you have to start with the loudest cleanest bass regardless of where the sound comes from. This is more an issue of component quality and sound tuning than location. The sound quality in my car was a good example. Many people had crappy systems with crappy tuning, and assumed that it sounded good because it was in a hatchback. Location is important too, but without tuning and sound quality, location is nothing.

6)I am not sure where you got your information, but steel readily propogates AND reflects sound. This is where the flat steel panels of your trunk come in. If the opposite were true, there wouldn't really be a need for sound deadening in the car would there? Ever stood inside an aluminum shed, wharehouse, shop, hangar or room? Ever noticed how much your little voice carries in that big space? Sound reflection. Ever heard a bumping bass system from 1/2 mile away or knocked on a big steel beam? Sound propogation.

See that is one of the nice things about bass. We hear its propogation as a vibration, which is all sound really is. It just so happens that bass is low enough to vibrate our entire body and not just our ear drum. In the process it vibrates the car, the ground, the guy next door and the guy the block over if it is strong enough.

7) You will need less dynamat on the deck if you mount them there, but of course if the trunk is rattling too, then you will have reflective sound from the sides of the trunk interfering with your sound quality, which is what the dynamat is there to prevent. Fortunately, there is enough reflection in the trunk area that it WILL degrade sound quality (even with dynamat on the rear deck) unless your subs are mounted in a completely separate enclousure attached to the parcel shelf and sealed off from the trunk, which again will more than offset the amount of weight for the dynamat in the trunk.

You came here looking for info, but clearly you know all there is to know about sound, so you should just go mount your subs with your cannon barrel port and be happy with how kick ass your system is.

**dwf137** · 12-21-2004, 02:22 AM

it seems like there's two types of people replying to this thread... the people who acutally know something, and the people who are thinking up ideas in thier head and pretending... which do you fall under, cuz were looking for people who acutally know something

on that note... bandpass boxes sound like shit, and are bad for your subs at high volumes. sealed boxes get you the best sound. a ported box will get you inbetween a sealed and a bandpass box, i prefer a nice slot ported box. slot ported boxes generaly are nice and tuned compared to the typical round ports, which the hole is pretty much just generic.

I suggust that if you're looking for sound quality, go with a sealed box.

A subwoofer is not ment to put out sound like a speaker or tweeter.. it's going to sound muffled becuase you're generaly cutting off sound at 150 hz, so all youre getting is very very low frequencys... if you get a sub that's loud enough, you're not going to be able to tell that it's in the trunk... and hell, if it bothers you that much, roll around with the back seats down..

put it in a sealed box, in the trunk and suck it up..

**pwrusr** · 12-21-2004, 02:47 AM

I know you were making a example, but 150Hz is just too high a cutoff freq for subs. they will sound much better with a cutoff of 80-100Hz *edit* at least that's how my subs sound**.

also here's a idea for the thread starter. From the inside of ths sub box bolt the sub to the car through the floor of the trunk. You'll have to take the muffler and heatshield off to bolt it up properly

that's what a friend of mine did, worked wonderfully

**JDMCB3Si** · 12-21-2004, 12:17 PM

I agree with whomever said something about replying to this thread and knowing something or trying to sound like you know something.

problemchild) There is NO way the windows (which are safety glass compared to single pane glass in a house window) in the car gonna break or crack from ANY form of sound or bass.
To answer your comment on the sedan and SUVs YES the subs DO sound better and flow better in a sedan than an SUV. In the SUV the sub enclosure is WIDE open. In the sedan it is sealed in the trunk. Sub bass is non directional and does not matter where you install them at cause the frequency coming out of them is non audible just felt.
Normal frequency cutoffs on any sub amp runs between 50-100 hz. this is called the low pass crossover. This is used to keep ALL frequencies above the cutoof from getting tot he subwoofer. They can damage and even melt the VC (voice coil) and basically weld it to itself.
If you want the sound coming directly in and do not want SLOPPY(bandpass box) or LOUD MUDDY(round ported box) bass then use a sealed enclosure and add an extra chamber where the subs fire into but seal it up with 2 6" round ports running up through the rear deck in turn giving you the open space box you are wanting.
Now for the loss of volume. where are you losing volume with a low frequency? The mids and highs throw out the volume and the lows throw out the feel. You will not get any more volume out of the subs being in a htach or SUV compared to being in a trunk. The vloume that your sub is going to perform its best at is all in the construction of the enclosure. if you put it in to small of an enclosure you are more than likely going to have bad "colored" sound coming out and it will take a lot higher db to get it to sound right. Now if you build the box correctly then even at low volumes that sub is going to POUND out like a tester firework booming in the sky and through your chest. there is now way to make a box to big because actual box size for the sub would be bigger than most small hatches.

I attached a pic that migh help as far as how i explained the box building.

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