http://elevenmagazine.files.wordpress.com/2009/09/bat-signal.jpg

I'm at the point where I'm redoing my package tray....again.
So I want to cut out the circle for the 12" sub now.
In your professional OPINION, is it really going to matter where I put the sub??
Trunk or Package tray ?? I figured the package tray looks cooler.....

Questions I have, I'm throwing out for the car audio experts because this is kinda above my pay grade.
I'm strongly considering a Alpine 12" Type R sub. 500W RMS DVC 4ohm.
(because my brother has 2 of them sitting he's not using)
There's also 2 Audiobahn Alum120's (http://www.sonicelectronix.com/item_4079_Audiobahn+ALUM12N.html) up there but 1000RMS isn't happening.

So I have 2 options to wire it up.
1. Mono amp @ 2ohms.
2. 2 Channel amp @ 8ohms.

What would be better and why ?? For some reason it's not clicking in my head. :confused:
http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/1DVC_4-ohm_mono.jpghttp://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/1DVC_4-ohm_2ch.jpg

When you say:

So I have 2 options to wire it up.
1. Mono amp @ 2ohms.
2. 2 Channel amp @ 8ohms.

What is "it"? I assume the Alpine sub? Or you looking at anything else?

I am not sure one way is "better" than the other aside from running your amp 2 ohms means it will run hotter, but if it's designed and engineered to continuously run at 2 ohms, then run it at 2 ohms. What's the output for each option? Do you have any particular amps in mind?

Re: placement of the sub. I have always wondered if a beefy sub that is properly powered would 1) run into too much package tray flex and 2) the sub directed toward the glass would somehow affect the glass and cause it the adhesive to eventually fail?

Personally I like the clarity of sound from having a sealed sub inside the drivers compartment. It is probably a matter of opinion and how much work you are willing to do but It wasn't too bad to put mine in the back deck. Package tray flex isn't really an issue depending on how you do it. I made a sealed mdf box and attached it to the underside of the package tray with angle iron and put a layer of dynomat on the top and bottom of the package tray. I don't have any pics of the bottom but here's one of it in.

http://memimage.cardomain.com/ride_images/2/4662/3161/24154080017_large.jpg

That's exactly how I was going to do mine ^ ^.
I just wasn't sure if it's worth the EXTRA work and hacking or not.

I took a breather for the night to recap and make sure I want to do this.
How did you cut the perfect circle required for the sub in the package tray ??


What is "it"? I assume the Alpine sub? Or you looking at anything else?

Well my brother just said he won't cough his up......I thought he would.
So I'm considering ALL options at this juncture but I heard the Alpine Type R's
are the best bang for the low buck. Mind you, I'm NOT into hip hop, this
is STRICTLY for rock n roll and heavy metal.

I have no idea what amp I'd buy just yet either, but I've never done an 8ohm load before
so I was curious about it. I know 2ohm the amp has to be 2 ohm stable because it's
working harder.

Do you have any particular amps in mind?

Kicker or Kenwood, but no specific model yet.
I'm testing the waters of which is a better route to go first.

I haven't done a sub in years so I forgot alot.

OK, let's look at what you're planning on doing;

Put a 12" woofer in your car with an amp: Style or substance?

If going for style awards, by all means mount it in the package tray. It'll look good. And that's about as far as I can recommend.

Why? Bass, while is non-directional below 200hz (and sounds like ass at that frequency; you're going for sub bass below 100hz), still has physics to deal with. Every frequency has a wavelength (which varies based on humidity, altitude, etc. but is pretty constant). A 100hz bass note has a wavelength of 11-12'. a 50hz note is double that! What does that mean to you? It means that you want to (in a perfect world) be at the end of that wavelength when the note hits. Guess what? It's not gonna happen, especially in the confines of a car. So what tricks can we do?

Well for starters, we can play with phasing; i.e setting the speaker 180* off of what it's supposed to be playing, to see if that helps bass or hurts it. Some amps even have a variable phase control so that wherever a particular note hits is right where you're sitting. Great for competition, but usually what happens is that you get one bass note that comes out of nowhere whenever it hits and you wonder what happened to the rest of the sound (plexiglass bandpass boxes are notorious for this).

The usual solution though is to mount the speaker towards the rear of the car so that the bass has to travel to the end of the trunk, make a U-turn, and then go back into the car itself. This takes advantage of the longer distance to travel and gives you better sound. Only potential is what's called a standing wave. This is where the sound goes out, gets reflected off the far end of the trunk, but then in turn cancels out the sounds coming from the woofer. Usually not an issue, but if you get MUCH better bass with either the windows or the trunk open than when closed, you've got a standing wave problem.

Next is wiring. If you're going with a monoblock, wire the speakers in parallel; i.e. 2 ohm. Since it's already a monoblock, you can run it at lower frequencies. On a stereo amp, when you bridge the amp (run both outputs to one speaker), whatever impedence you're running at the amp sees half of that. That's why you use serial wiring to get 8 ohms. Do NOT run a stereo amp bridged at 2 ohms. It'll see 1 ohm, and for the most part that's a bad trip. Oh, and unless you know the exact specs, build a sealed box. Much more forgiving and require less airspace. Those Type R's need 1 cubic foot sealed and 2 cubic foot ported. And as far as which is better? I'd go with the monoblock; more power for less size due to Class-D technology.

Hope that helps some....
Jason

Wow.....I just gots me an edumication. :D

Holy sh** I'm a total dumbass and knew NONE of that. :crazy:
Okay, so now I feel TOTALLY helpless and I need some recommendations.
So the package tray deal is out. I'll just do a sealed box like this then right ???
(minus the side port obviously)

http://ecx.images-amazon.com/images/I/41uHxyJla%2BL._SL500_.jpg

I guess I've been hacking things together for years.
I will PM you since you've got a PhD in stereo physics and I'm still an amateur.

No PhD, just alot of learning the hard way so that others (i.e. guys like you) can learn from my experience!

Since you're not sure what woofer you'll be using now since your brother decided to crawfist his subs, consider a 10" instead of a 12. Most of the better ones will work in a half cubic foot of airspace as opposed to the full cubic foot. Trust me, on Camaros, trunk space is not something to take lightly. We can barely fit one body in there, let alone a body, golf clubs, and a subwoofer!! Heck, you could do 2 10" woofers in the same airspace as 1 12" woofer. Besides, if want to feel bad, take a one cubic foot 12" generic sealed box and try to fit it in the car. Let me know how that went for you (it won't fit if you try to close the trunk lid).

Here are two pics of my trunk with my trunk mounted battery:
http://farm5.static.flickr.com/4141/4912420452_a924a9b4fd_z.jpg
http://farm5.static.flickr.com/4136/4912419988_86e321bed8_z.jpg

As you can see, it's just one 10" sub facing rearwards.

Hope this helps some.
Jason

Mind you, I'm NOT into hip hop, this
is STRICTLY for rock n roll and heavy metal.

Maybe Batman can comment, but a quality sub should be able to accurately reproduce bass regardless of the genre of music. In short, try to find a sub that is known for being transparent. :)

Here are a few "lesser known" companies that make quality subs that you might check out. Adire Audio used to be another but they closed their doors.

Digital Designs: http://www.ddaudio.com/

Elemental Designs: http://www.edesignaudio.com/

Image Dynamics: http://www.imagedynamicsusa.com/

Besides, if want to feel bad, take a one cubic foot 12" generic sealed box and try to fit it in the car. Let me know how that went for you (it won't fit if you try to close the trunk lid).

LOL! I remember trying to squeeze my 1 cu ft box in my 76 trunk and it was a pain in the a$$!! I made it work, but it was not really ideal - I had to move it all the way forward and it was just awkward looking. So getting a stout 10" sub might be an excellent compromise as you suggested,

Batman knows his stuff. He hit the nail right on the head when it comes to wavelength.

There is one thing that wasn't mentioned. The rear windows on 2nd gens are pretty close to a glass hatch, ie hatch back vehicle. Every system I ever did in a hatch that was an SPL car, we used the reflective qualities of the glass to our advantage. We played with rearward firing, frontward firing and upward firing woofers. In these cars the upward firing SPL was always higher.

So, the question is......would our rear window act in the same manner as the glass hatch? I no longer have the time to play with subwoofer placement since I now have two jobs and a family, but if somebody does I'd be interested in how the results would be.

Also, I noticed you are trying to use a DVC woofer to run mono. The only way you could run the sub at 2ohms is if the amp is stable into that load. If you were to measure the impedance at the power supply of that amp into a 2ohm load it would read 1 ohm, because an amp run mono is the sum of two channels cut in half.

I would be careful running an amp at a 2ohm mono load. The amplifiers of today are nothing like the ones we all used and loved in the 90's. They are built cheaper with smaller capacitors and traces. I just would hate to see you get it all done a smoke an amp after all that hard work.

Let us know what you decided. I'm anxious to see.

http://farm5.static.flickr.com/4141/4912420452_a924a9b4fd_z.jpg
http://farm5.static.flickr.com/4136/4912419988_86e321bed8_z.jpg

^^^I've always liked Rockford^^^

Since you're not sure what woofer you'll be using now since your brother decided to crawfist his subs, consider a 10" instead of a 12. Most of the better ones will work in a half cubic foot of airspace as opposed to the full cubic foot. Trust me, on Camaros, trunk space is not something to take lightly. We can barely fit one body in there, let alone a body, golf clubs, and a subwoofer!! Heck, you could do 2 10" woofers in the same airspace as 1 12" woofer. Besides, if want to feel bad, take a one cubic foot 12" generic sealed box and try to fit it in the car. Let me know how that went for you (it won't fit if you try to close the trunk lid).

Okay, so I'll just do a 10" rear firing then. I didn't know the 12" wouldn't fit. I like your box setup. If one 10" works for you, it will probably be good enough for me as well. Pretty smooth how it hides it all. I like that. I've been debating the rear battery setup too.

The main 2 reasons I wanted the package tray setup was Dale Earnhardts car, plus my 98 Lexus has an 8" upward firing in the package tray as well. I thought this was the new design setup that worked better. It's nothing crazy with bass, just some extra. I wanted a little more then that tho.
http://www.carstereoremoval.com/images/LexusES300RDeckSpkR0324049901xP.jpg
I will look at the same amp you suggested and a smaller sub option along those lines. Flea markets around here have boxes dirt cheap. Thanks guys, at least now I know I can finish my package tray and begin fabbing my box underneath it. :cool:


Also, I noticed you are trying to use a DVC woofer to run mono. The only way you could run the sub at 2ohms is if the amp is stable into that load. If you were to measure the impedance at the power supply of that amp into a 2ohm load it would read 1 ohm, because an amp run mono is the sum of two channels cut in half.

I would be careful running an amp at a 2ohm mono load. The amplifiers of today are nothing like the ones we all used and loved in the 90's. They are built cheaper with smaller capacitors and traces. I just would hate to see you get it all done a smoke an amp after all that hard work.

Let us know what you decided. I'm anxious to see.
Yeah I know he's been in the industry, so he's like the "Go to" guy for in depth shizzle that makes yer head spin. :p
I'm not set in stone on any subwoofer. I just thought the DVC's were better subs. I was eyeballin Kicker CompVR's too.
I heard the L7's were the primo options besides the Solobaric square one's but I'm not spending that much.
I'm not THAT much into bass......maybe if I did hip hop or something I would..

As for the amps, yeah the amps I bought in the 90's lasted 10 full years of heavy abuse with my Kenwoods.
I'd still have them if some punkass little bitches didn't rob my truck outside a theater.
That's why I didn't want to buy anything else. You'd hear my stereo coming before the car.

Subs I never bought high end, but I didn't want generic Walmarx crap either :p

So what is your budget?

For the sub and amp I'm trying to stay $300 and under.
You have to realize, I have to do this for 2 cars, so that's $600.
I know that's not a HUGE budget, but it's midrange.

I'm trying to stick with brand names I've heard of like Kicker, Alpine, Kenwood, Boston Acoustics, etc
Sony and Pioneer for the most part have sold their souls to Walmarx and that's crap.

BATMAN please call me back!!

For the sub and amp I'm trying to stay $300 and under.
You have to realize, I have to do this for 2 cars, so that's $600.
I know that's not a HUGE budget, but it's midrange.

I'm trying to stick with brand names I've heard of like Kicker, Alpine, Kenwood, Boston Acoustics, etc
Sony and Pioneer for the most part have sold their souls to Walmarx and that's crap.

It can be done, but you might have to search for some "last year" models to achieve that. There is a pretty good swap meet type section at www.caraudioforum.com that you might check out. I have bought stuff from people there with good results. Just stick to buying from people who have high post counts :D

For the sub and amp I'm trying to stay $300 and under.
You have to realize, I have to do this for 2 cars, so that's $600.
I know that's not a HUGE budget, but it's midrange.
.....

For $300... Infinity Basslink II powered subwoofer (http://cgi.ebay.com/ebaymotors/INFINITY-BASSLINK-II-2-POWERED-SUBWOOFER-ENCLOSURE-BOX-/190424647200?pt=Car_Audio_Video).

I have one, my son has one and Pixels has one.
We all have the auxillary amp (4x50) for it and that's the only amp in our systems.

http://i.i.com.com/cnwk.1d/sc/31694212-2-200-0.gif

The amp is another $100 if you go that route. ($350 total)
If your head unit puts out 40 watts per channel, you won't need the aux. amp.
The only problems we've had is: My son had to replace his Basslink but we think that was due to water leaking into his trunk. :mad:

http://www.rockfordfosgate.com/products/product_details.asp?cat_id=17&series_id=56&family_id=279&item_id=113960&locale=en_US&p_status=

This any good?

Man that aint cheap

http://www.rockfordfosgate.com/products/product_details.asp?cat_id=17&series_id=56&family_id=279&item_id=113960&locale=en_US&p_status=

This any good?


Dimensions H 11" x W 21.25" x D 15.25"

I doubt it will fit in a Camaro trunk.

Anyone know the height space between the package tray and trunk itself ???
As well as the space between 6x9's to put a box ??? (yes I'm lazy and it's late) :p

I measured out a few sub boxes today at Fry's.
12" single was 16" tall $36
10" single was 13" tall $30
But this is what was weird.....
10" dual was ~14.25" tall....:confused: $49

"Surface area of a circle is pi x (radius x radius) so a 10" sub has a surface area of ~ 78.5"2 while a 12" sub has a surface area of ~ 113"2. As you can see, that 2" of diameter means a BIG difference in surface area. The square 12" Kicker has a surface area of close to 144"2 (what their ads are all about... more surface area.) If you want big booming bass, go for 12" or 15" subs. If you want a strong bass but not going for the biggest bass you can, get 10" subs and save some trunk space. a good rule of thumb is that 10" subs need about .75 cubic feet each and 12" subs need about 1.25 cubic feet of enclosure. Two decent 10" subs with the proper box and good power will rattle your car and shake the rear view mirror, don't think that 10's are weak.."

Man that aint cheap

Especially when you can build it separately for less then it costs. ($600+)

The infinity option is nice Terry but it doesn't appear to have the necessary cubic footage
to make full use of that 12" sub. It is a GREAT option for those looking for plug and play though.

Make your own box! :D

That's kinda why I'm asking. :)

I am kinda leaning that way. It will be cheaper and I'll have fun doing it.
I just bought a jig saw, but I'm not confident in my ability to cut perfect circles.

Aces, that 8" sub I was talking about putting under the stock 6x9 opening is this one:

http://www.crutchfield.com/s_107MM840D/Polk-Audio-MM840D.html?tp=111

I chose it because it's fairly compact height-wise, is DVC, and has decent power handling for each coil and only needs a .35 cu.ft sealed enclosure. Keep in mind that I'm planning on running only a front stage and running the R/L rear channels of a 4-channel amp to each side of the sub, so it all stays 4 ohms at each coil.

This was the best way I could come up with to have decent bass and a budget with integrity.

Edit: NOT running the R/L rear channels into a DVC... been informed that this is NOT the intent of DVC. :screwup: New plan is my old plan: bridge a PDX-F4 into a 2-channel for the front stage and run a separate mono amp into one of these JL 8" subs:

http://www.crutchfield.com/s_1368W3V34/JL-Audio-8W3v3-4.html?c=3&tp=111&avf=N

Okay price, and makes good use of the 6x9 hole. Then like what Bikefxr said a few posts later than this, except with a simple sealed enclosure. The whole Bose passageway thing is WAY out of my league.

That's kinda why I'm asking. :)

I am kinda leaning that way. It will be cheaper and I'll have fun doing it.
I just bought a jig saw, but I'm not confident in my ability to cut perfect circles.

Don't use a jigsaw to cut circles, use a router and a perfect circle jig.

Some fry's make custom boxes I think, you should stop by their install bay.

Some fry's make custom boxes I think, you should stop by their install bay.

Well I just emptied my trunk and looked at it. :screwup:
Dude this trunk requires a very abstract designed Picasso box to even fit right.
I forgot how jacked up and funky it is under the package tray. :confused:

It's got humps and bumps all over the place. I'm starting to lean back
towards the package tray deal and just go for simplicity over function now.

So it most definitely MUST be a custom box because I haven't seen sh** that will fit something like this.
I'm also leaning back towards the 12" for the hell of it. I dunno.....gotta stew on it for a bit.

Don't use a jigsaw to cut circles, use a router and a perfect circle jig.

Great....another tool I gotta buy. LMAO thanks.

I've never used a router and I knew eventually I'd need one.
That just saved me a bunch of headaches because I was going to try the jigsaw.

Would a Rockford Fosgate Punch 3 10" (H 13.125" x W 31.125" x D 15.75") sub box fit in the Camaro's trunk?

http://www.rockfordfosgate.com/products/product_details.asp?cat_id=17&series_id=56&family_id=103&item_id=113340&locale=en_US&p_status=

Not under the package tray. Under there behind the seat there's only ~11" of
clearance with some major humps in the trunk tray so it's not exactly 11" either.

But in the trunk like this, yeah.
http://www.nastyz28.com/forum/showpost.php?p=1910433&postcount=16
Just don't aim them UP at the trunk lid.

My trunk space is important to me, so I'm going to fab a custom box and it will
look like Batman's or CRhead1's
http://memimage.cardomain.com/ride_images/2/4662/3161/24154080013_large.jpg

All I have for a router is a Craftsman, nothing speacial, just a sale special. I also bought a circle jig from them, but you can make one easily yourself. Just buy some carbide raouter bits.

You can also buy this.....

http://www.youtube.com/watch?v=-61bH15tJmw&feature=related

Or this....

http://www.sears.com/shc/s/p_10153_12605_00925179000P?prdNo=12&blockNo=12&blockType=G12

^ Damn that's pretty cool!! Never seen something like that.

It's $60 with a bit. But I also need the router tool itself.
That really takes the guesswork out of cutting PERFECT circles or ellipses.

I saw this is the cheap way of cutting circles with a router.
http://www.woodworkingtips.com/etips/images/102000sn_1.gif

Well, I learned something...I always thought when people put their subs in the trunk that they were just not creative enough to find a space for them without taking up trunk space, which as someone pointed out, isn't all that generous to begin with in our cars. The thing about waves having to go to the back of the trunk and do a u-turn is news to me. With subs in the trunk, I don't picture how the sound gets to the front of the car where one's ears are though, unless there is a hole in the package tray, or no rear seats. Or is it all about vibrating the body of the car so you don't really hear it per se?

I have mine (10" Infinity Kappa) mounted in a sealed box which is mounted under the package tray, so that the sub fires into the passenger compartment. For what it is worth, it works fine, and I can't imagine needing more bass than that.

Aces, building a box is not that difficult, and you don't really have to cut a "perfect" circle. At least with my sub, it "top mounts" into the hole in the box, so it doesn't show--it just has to be good enough for the speaker to seal the opening. And... if you wanted to, you could rig up a deal to cut a circle with your jigsaw. Something as simple as a string attached to the center of where you want to cut your hole, and just let the string define the radius of the circle as you cut. A router will cut cleaner but if you are just going to do it once or twice probably not worth getting it just for that.

First off..im no professional stereo installer nor have I ever been, but the jigsaw has always worked for me. I use the cardboard cutout inside the box the sub comes in as a template. Just go slow and wear safety glasses and its really hard to screw it up so bad that the sub wont seal. Im not trying to argue that the router is not the right way to do it, but if you dont already have a router I would not buy one just to make a hole in a box. Jmo

First off..im no professional stereo installer nor have I ever been, but the jigsaw has always worked for me. I use the cardboard cutout inside the box the sub comes in as a template. Just go slow and wear safety glasses and its really hard to screw it up so bad that the sub wont seal. Im not trying to argue that the router is not the right way to do it, but if you dont already have a router I would not buy one just to make a hole in a box. Jmo

I was just making a recomendation on a better way to cut circles. Jigsaws work, but the router is a better way. Also, you can cut a reccess before you cut your circle incase you want a flush mounted woofer.

With subs in the trunk, I don't picture how the sound gets to the front of the car where one's ears are though, unless there is a hole in the package tray, or no rear seats.



Bass is omni-directional so it doesn't matter where you place the sub in the car, as long as the crossover point is low enough. If your crossover point is in the midrange or midbass range..then the sub position tend to be more noticable.

Bass can find it's way into the cabin of the car through fabric in the seats, but metal not so much.

I'm not a big fan of mounting subwoofers in the trunk without some sort of ported system to vent into the cabin. To me putting a sub in the trunk of our cars with the steel barrier behind the seats and package tray is just wasted energy, I also don't understand why people build boxes under the rear deck and fire the sub towards the rear with a flat baffle trimming the face of the box out, seems like a wasted effort...again that's my opinion.

I've been doing car audio since 1989 and some of my best sounding cars were hatchbacks, with the sub firing up towards the rear glass. This provides a bass boost using the cabin gain or transfer function provided by the design of the hatchback. It was a totally different sound that say a pick-up with the sub behind the seat firing into your back.

Since our 2nd generations have a trunk, the most logical place for me to put my sub was in a box suspended from the rear deck firing into cabin through a hole I cut in the package tray. I supported the subwoofer box with angle iron and sealed it with a combination of sound deadening and foam sealing strips.

The design of our rear glass in our cars should provide a bass gain similar to the hatchback cars I used to have because they have a sharp slope to them.

I can't see doing it any other way, but again that's my opinion.

http://i227.photobucket.com/albums/dd180/1982corvettedude/DSCF3823.jpg

That looks very similar to the way I did mine. :) The thing I like most about it is that it doesn't take up the whole trunk.

http://i68.photobucket.com/albums/i40/dshaman/Camaro%20stereo%20and%20sound%20proofing/Slide9.jpg

Well I just emptied my trunk and looked at it. :screwup:
Dude this trunk requires a very abstract designed Picasso box to even fit right.
I forgot how jacked up and funky it is under the package tray. :confused:

It's got humps and bumps all over the place. I'm starting to lean back
towards the package tray deal and just go for simplicity over function now.

So it most definitely MUST be a custom box because I haven't seen sh** that will fit something like this.
I'm also leaning back towards the 12" for the hell of it. I dunno.....gotta stew on it for a bit.



Great....another tool I gotta buy. LMAO thanks.

I've never used a router and I knew eventually I'd need one.
That just saved me a bunch of headaches because I was going to try the jigsaw.

There is nothing wrong with using a jig saw. He is right, a router will make a PERFECT circle, but a jig saw will make more than a sufficient circle. I have done it many times w/o any problem. Just take your time. :)

BTW, I was able to fit my 12" Solobaric (old round style) box in my 76 trunk back in the day, but it took a little work. I am pretty sure your trunk is the same as mine.

You might make some templates out of cardboard and see what you can fit in there. Will be a big time saver. Remember that you can get away with making a box that has a front face that has a slight angle to reduce the height.

I'll chime in a bit because I DID do it professionally for several years. There is a lot of good info in the thread. A lot of good theory. Problem is that when we have budgets and varying levels of install and fabrication ability, so concessions must be made. On installs where $ and time wasn't an object, I'd construct a box that took up the entire under-tray area. A single 8 inch sub crossedover at 150hz with a 12 db slope was all we needed. The sub was mounted entirely inside the box at on extreme end on the bottom 1/2 ..and faced the other end, where the wave was redirected via internal construction back towards the source, but in the upper half ( basically a rectangular box with a false floor..sub in the bottom). Wave redirected into a 6x8 port on the top of the box directly into an exact matching hole in the tray. Wave bounces off the glass and forward. the entire wavelength was 12 feet +/-. Hard-hitting bass out of a single driver and 200W mono. problem is that this box took 2 full days to build and fit tight, loss of the defogger, and the 6x9's had to be swapped to 6 inch mids spaced to the far end of the package tray, sealing up the unneeded holes between the trunk and pass compartment. $$$$$. Boxes are much more than something to hold the speaker. A proper box can greatly enhance the speaker performance...and can seriously amplify the volume thereby requiring less amp and speaker for a given volume. Loaded Horn speakers show this theory well. A Megaphone driver is about 1inch in size....but the mechanical amplification from the horn makes it much much louder. A proper box does the same thing. A proper box also acts as a shock absorber for the speaker cone. BOSE is the leading company in mechanical amplification. I am always amazed at how much volume they get from 3 1/2'' drivers in their desktop radios. Those little speakers send a wave through a port about a foot and a half lond before exiting.

Anyhow, when dollars were down...we used a single 10" sub mounted in the middle of the tray. 12" subs tended to be boomy, 8" subs were tight but couldn't quite give the volume. A 10 fit well and still hit hard and had a nice tight sound. A drum hit should feel like a smack in the head..not a whoosh.
the key is to use a sub designed for bigger volumes. These are called Free-Air subs....they are designed to work without a box and mounted on an infinite baffle (meaning a flat plane whereby the waves on the front of the speaker will never mix with the waves from the back of the speaker. Remember..there is as much air moovement behind as there in in front..and if they meet, it muddies the sound horrible. So seal up the tray with dynamat, drop the free-air 10 in there. Free-air subs require a bit less amp because they don't have to move the cone against pressuruzed air inside the box. I also would recommend stiffening up the tray. Some MDF undeneath screwed and glued to the tray works fine. Sometimes we'd lay some 3/4" MDF on top of the tray, screw and glued, and then mount the speakers in from the top. This gave the tray a lot of mass to prevent rattles and noises...kept trunk space use to a bare minimum, and then we'd make a grille cover to cover the whole tray in a nice matching grille cloth for that factory look. I never liked seeing speaker grilles...look like some alien designed them. Free air subs should be crossed over at a slower rate. Most cars have a natural resonance at about 75Hz..so if the amp has any EQ capability..you can nudge the 75hz crossove down. This gets rid of the thrumming and boom I hear all too often. Bass is music, not noise.

Class D amps are fine. They are real workhorses. 100w of real RMS power is fine for a sub amp. I always used 4ohm drivers because 2 ohm could get the amp into trouble because a 2ohm nominal speaker will easily see 1/2 ohm or less on a big hit. 4 ohm also used to cost a bit less. I always liked JBL drivers....and you can steal them off evilbay direct from the HK factory refurb store. I see $200 drivers for $50 all the time. Run a single sub in mono from the head unit. Don't bridge stereo inputs into a mono signal because there is information ont he channels that is 180d out of phase and it will cancel itself out causeing audible holes. The signal mixing should be done as early in the signal stream as possible. If the head unit has a mono sub output...you're gold.

Mount your sub, cross it over at about 150hz. Mount your 6x9 coaxials in the factory holes and use a bass blocker or the amp crossover to eliminate anything under 250hz at a soft slope. You'll have nose-bleed volume, but it will be nice and clear as well with good definition. Perfect? No way. Audiophile? No way. But for the other 95% of us, it will be quite pleasurable and satisfying.

Getting into too much detail, lost in micro-theory, in a car environment is a waste in a street driven car that wasn't rebuilt to be a housing for the stereo. There are so many environmental intrusions, leaks, rattles, reflected sound, outside sound and the like that going crazy to get a perfect wave length is an effort for the truly over-the-top types. I've done installs from $400 to $10,000 and I will tell you this right off..money does not always equal quality. I've heard systems that had thousands of dollars in tuning hours sent to get a perfect flat response...and it sounded like crap to the ear. Put a human body int he cabin and the meausrements went all to hell because of volume changes, reflectivity changes...the more exact it gets the less room for error or change there is. But on the other hand, a single sub, 4speaker, bi-amped system with a crossover tuned by ear had some of the most enjoyable sound I've ever heard. We ain't driving anechoic chambers..we're driving cars with tranny nose, engine noise, muffler noise, tire noise, significant other noise. It's a crappy environment, make the best you can with it. Keep it simple.

http://i227.photobucket.com/albums/dd180/1982corvettedude/DSCF3823.jpg

^^^THAT'S CLEAN^^^

We ain't driving anechoic chambers..we're driving cars with tranny nose, engine noise, muffler noise, tire noise, significant other noise. It's a crappy environment, make the best you can with it. Keep it simple.

I agree with this.

Okay....after reading Bikefxr's rocket scientist response my eyeballs are doing this. :crazy:
I had to re-read it about 3x to make sure I grasped it all .....got 80% of it.
http://img.hexus.net/v2/gaming/screenshots/crosseyed.jpg


Anyhow, when dollars were down...we used a single 10" sub mounted in the middle of the tray. 12" subs tended to be boomy, 8" subs were tight but couldn't quite give the volume. A 10 fit well and still hit hard and had a nice tight sound. A drum hit should feel like a smack in the head..not a whoosh.
the key is to use a sub designed for bigger volumes. These are called Free-Air subs....they are designed to work without a box and mounted on an infinite baffle (meaning a flat plane whereby the waves on the front of the speaker will never mix with the waves from the back of the speaker.

A free air sub will interfere with 6x9's sharing the same space no ??

This Crutchfield sub box info page says ported boxes are best for my metal genre.
http://www.crutchfield.com/S-q2XMpD3FQFw/learn/learningcenter/car/subwoofers_enclosures.html
However, I'm hearing the sealed boxes are for the best sound quality.

BTW Thanks for EVERY SINGLE suggestion.

I'm definitely going to buy a router, just because I'm anal about doing things right. I know I don't need a PERFECT circle, because the sub WILL seal up against a jagged circle no problem. However, it will urk the absolute crap out of me if I don't cut it perfect. I'll feel like I half assed it.

I want my first sub box to be made to about a 9 out of 10 or a 10. Besides, I want to get into wood working too now since I'm not going out to bars as much anymore and both my cars are done. I need more to do.

Bikefixr... Great response!!!!

What you described is what Bose calls a Wave Guide. (They've learned their audio physics well!)

I had never thought of building one for a sub enclosure in the trunk of a car!

Would it be possible to use two guides in the box to lengthen the wave travel and get by with a shorter box?
(And still have room for 6x9s in the stock location and maybe even use the defogger hole as the sub port?)

Kinda like this:
http://i33.tinypic.com/2u5fdrk.jpg

Aces.... You can work out the frequency harmonics and get busy designing the box. ;)

If that's what he was talking about doing,
I'm totally lost on how to implement something like that with a sub.

Good luck you have more info that you know what to do with now you are lost and dont know what to do. I know I have a buddy that does sound compition and he does all my work and I dont question anything he does.

Class D amps are fine. They are real workhorses. 100w of real RMS power is fine for a sub amp. I always used 4ohm drivers because 2 ohm could get the amp into trouble because a 2ohm nominal speaker will easily see 1/2 ohm or less on a big hit.
I am going to buy a class D Kenwood KAC-9105D (http://www.kenwoodusa.com/Car_Entertainment/Amplifiers/KAC-9105D) amplifier for a SINGLE 10" subwoofer.
Now with THIS ^ MONO Class D AMP in mind,......

I should look for a SVC 4ohm load Subwoofer OR a 2ohm DVC load subwoofer
wired like this (http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/1DVC_2-ohm_mono.jpg) (series?) to get a 4ohm load to the amp. Correct ??

Okay....after reading Bikefxr's rocket scientist response my eyeballs are doing this. :crazy:
I had to re-read it about 3x to make sure I grasped it all .....got 80% of it.
http://img.hexus.net/v2/gaming/screenshots/crosseyed.jpg



A free air sub will interfere with 6x9's sharing the same space no ??

This Crutchfield sub box info page says ported boxes are best for my metal genre.
http://www.crutchfield.com/S-q2XMpD3FQFw/learn/learningcenter/car/subwoofers_enclosures.html
However, I'm hearing the sealed boxes are for the best sound quality.


I don't think there is a such thing as free air subs for the car audio environment anymore. If someone still makes them I haven't seen them. Back in the 1990's when infinite baffle subs were still popular the average sealed enclosure was about double what it is now. During that time you could buy a speaker specifically designed work without a box and loaded into a trunk.

The sound you get from mounting the sub to the package tray and using the trunk is WAY different than a sealed enclosure, or even a ported enclosure. My first car was a 1978 camaro (circa 89) and had a shop install a pair of Coustic 12" subwoofers behind my seat on a baffle board and used the trunk as the enclosure....it didn't sound too bad inside the car.

I did notice that the bass would sounded weak, and would almost disappear when in gear and going done the road, the engine drowned it out. I eventually blew my 6 x 9's.

For the heck of it, I removed the subs and installed them in a particle board box behind my seat....HUGE difference. I eventually bought a 1979 mustang hatchback and transfered the whole stereo, amps and all into the new car. I built a new enclosure for the subs. You would have thought I added two more subwoofers when I changed cars. The bass would knock your breath out, felt like a jackhammer.

I am going to buy a class D Kenwood KAC-9105D (http://www.kenwoodusa.com/Car_Entertainment/Amplifiers/KAC-9105D) amplifier for a SINGLE 10" subwoofer.
Now with THIS ^ MONO Class D AMP in mind,......

I should look for a SVC 4ohm load Subwoofer OR a 2ohm DVC load subwoofer
wired like this (http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/1DVC_2-ohm_mono.jpg) (series?) to get a 4ohm load to the amp. Correct ??

Dual 4-ohm. :crazy:

Dual 4 ohm like that BA Sub would give me a 2ohm load to the sub right???

Or is there a way to get a 4ohm load to the sub with them ??
Sorry, couldn't find the answer to that last night and I wasn't sure if running the amp in 2ohm was safe or not.

Didn't want to bug ya. :D

Twisted; Great pics...exactly what I was describing but lacking in the ability to make the picture. Waveguides are an awesome approach in some instances. Klipsch di a lot of research in the 50's and 60's, BOSE took it to a new level. Remember to put polyfill fiber in the box to dampen errant waves. I would also just glue in some small pieces along the path so that it wasn't a rectangle or square path along the length of the guide. Reason was to eliminate relfected waves..sort like stealt technology for sound. Odd angles keeps the waves from intersecting and coalescing. I always got blown away what a single 10" sub could do.

Free-air subs are far and away the easiest to set up..but they do lack some efficiency so you need to drive them a bit harder,or go up one size. I always preferred 2 8" subs to a single 12". The big subs just got muddy sounding na car...especially at that critical 75hz range where the cars natural harmonics would interfere.

Aces....a single sub won't interfere with your 6x9's much. Certainly not in an audible way. Too much air volume in a trunk to absorb the increased pressure..and most 6x9's have a fairly stiff voice coil and surround so they don't get blown up. What I have done is to make something up llike the factory speaker covers..fill with felt cloth and mount under the 6x9's. This gave the 6x9's some added damping and also isolated them from the trunk environment. MTX makes poly-something covers that do the same thing..i use them in doors to keep the door speakers dry and out of the elements. They make then for all kinds of sizes. Crutchfield sells them.

Now, putting a big sub in a box and also mounting other speakers in the box...that will certainly cause the smaller speakers to move with the increased pressure in the box. Sometimes...and this works well if you are putting a big sub in a box that is too damned small...you can either use a small diameter port about 18" long to vent the box...or you can add a small passive radiator. It's a woofer with no voice coil..just a a frame and a cone with a very loose surround. The pressure inside the box forces the passive radiator to extend outward at a lower frequency. Passives can fill in the drop-off that most subs have at 50hz. Passives can extend response down to 20hz. Think of them as a shock absorber for the box that fools the sub into thinking the box is bigger that it really is.

Bikefxr, a big thank you for sharing your knowledge on the board. Your explanations are simple and effective. :cool:

I'm a little confused here in regards to the sub positioning (package tray vs firing rearwards). It was said earlier in the thread that it is better to fire the subs towards the back so the wave will turn around and come back towards the driver. Someone else also mentioned that the metal behind the rear seat would possible restrict the sound wave. So which is it?

My experience has been with Hatchbacks and cars with fold down rear seats so never had to worry about the metal interfering. I run a pair of 10" JL Audio W3V2's in a sealed box powered by JL Audio 500/1. My amp was stolen so I'll be needing to get another one of those.

I'm pretty confident that I could stick my box in the back of my firebird and face it rearward and then build a false panel to smooth things out however if it is better for the sound i can just as easily cut 2 holes in the package tray and hang the box from a sheet of MDF.

Here is a good pic of what i'm talking about

http://i89.photobucket.com/albums/k208/johnsma22/DSC02615.jpg

this from Johnsma22 at transamcountry
http://transamcountry.com/community/index.php?topic=32653.0

Ace. I have a box for two 10's that fits in the back of my '71. I don't have subs for it, so it's just taking up space.

May be more than you want, but thought I'd offer if you'd be interested in buying it.

I'll get a pic up tonight.

BTW, I'm also very experienced in box building. If you need a hand, let me know. I'm off all weekend.

Subs firing backwards has several problems. First is that the wave will fire towards the back of the trunk...where some of it will be reflected backwards..some of it will be reflected all over the place. When the reflected waves intersect the originated waves...they may neutralize each other. Also, you're going to have standing waves which cause horrible boomy noise. Then, whatever sound energy is left has to go though the seat cushions and hopefully into the pass compartment. The whole rear-firing thing was started by the guys in the sound-off shows who wanted everyone to see the multitude of drivers. Not good for sound..good for showing off. There are enclosed boxes called isobaric boxes..and others that use the box design to create a mechanical amplification ...but these get expensive and complicated. Most of our people here just want some affordable, decent sound and still be able to hear the car, too. Audiophile grade install work is outside the realm of what most of us can do. I can tell you from experience...I've done these cost is no object installs....and when done, after hundreds of hours of install work, fabrication, tuning with a white-noise generator....these systems sound very very good....under extremely limited circumstances. These are show-systems, not for daily drivers. In fact..to my ear, many sounded like crap because while a sound meter can measure the flat response...flat respnse just does not sound great..it sound dead and hollow. Most systems need a boost in the 100-200 hz range, a dip in the 100-1200 range, and a boost in the 10k range. This compensates for road noise, interior relections, lousy interior speaker placement, old ears and believe this...when the music is mixed in the studio...it is not mixed to be audiophile-neutral. it's mixed for the audience who buys it...so they boost the bass and the highs a bit to compensate for the deficiencies of the human ear. A microphone is perfect, our ears are not.

So, put your subs in a convenient place, as unobstructed as possible, with a good amp, a good and properly adjusted crossover and be happy.
Also, here's a tip. if you are running two subs..run them in stereo..not mono. The bass signal on the CD has a significant amount of midrange material in it..so going mono takes some of your stereo signal and jams it together and plops it in the middle of the bass note...it lessens the stereo effect and moves the soundstage to the center. I always run 2 subs in stereo. Listen to some old WHO....or Pink Floyd. The bass actually moves across the 2 sides. the original percussion was miked with 2 microphines..so there is definite left and right percussion. 2 8" in stereo are better than 1 big honkin' 12 in mono.

Ace. I have a box for two 10's that fits in the back of my '71. I don't have subs for it, so it's just taking up space.

Got your PM. Can't use the duals because I want trunk space.
What are you looking for on the single 10" box and give me the measurements.

BTW, I'm also very experienced in box building. If you need a hand, let me know. I'm off all weekend.

How far are you from Schaumburg ?? You're by Kankakee right ??

This weekend I'll be in Vegas (or jail) with 5 Army guys fresh back from Afghanistan. :crazy: So it will have to be another weekend, but I do appreciate the offer. :)

I priced out routers, and I almost choked.....so I might not be just dumping $200 so quickly on the router. Do you have one a router and do you know how to cut the circles perfectly ???

If it can be cut, I can cut it.

Well I got this far with the sub box / amp tray today.
I leave for Vegas, so it will be finished with carpeting or vinyl next week.

http://i46.photobucket.com/albums/f122/Aceshigh22/LS1%20Implant/CamaroSubBoxnearcompletion.jpg

Bottom is 40"W x 14"D (2" deeper for amp dimensions, it's backwards in pic)
Top is 21"W x 12"D (12" is the maximum F > R inside room under package tray, this piece isn't in pic)
Front and rear are 15"W x 8"H (Height is 9.5" total with 3/4" MDF)
Sides are 10.5"W x 8"H

Altogether the interior of the sealed sub box will be
8" x 13.5" x 10.5" = 1134 cubic inches = 0.65 cubic feet.
1 cubic foot is 1728 cubic inches

Sub only requires .5 cubic feet so I'm a little over, but wasn't sure if that was with sub installed or not.
I have to cut the top piece circle hole, fabric the box, and install the wiring ports.

Looks good. Doesn't look like you need my help. ;)

What's the recommended enclosure volume for that particular sub?

What adhesive did you use?

I used a nailing gun, and caulking to seal all the corners.
I made great use of the Home Depot wall ripper saw to cut one big sheet of MDF. :cool:
I have enough to build a 2nd bigger box + shelf for my 442 as well.

Sub is the one from my other poll. The Boston Acoustics G210-44 DVC
It only needs .50 cubic feet of space in a sealed enclosure.

http://www.crutchfield.com/s_065G21044/Boston-Acoustics-G210-44-DVC.html?tp=111

http://a248.e.akamai.net/pix.crutchfield.com/ImageHandler/scale/340/342/products/2010/9/065/h065G21044-f.jpeg

Looking good Ace. You work quick!

Any idea what that whole thing weighs?

Less then 10lbs I would guess. I will have to fabricate some angled iron support brackets to hold it securely in place. If I didn't have to have a HOA bord meeting last nite it would have been done. All straight cuts so its simple. My neighbor has 2 routers and said he will help since he does a lot of woodworking.....WOOT!!

10lbs aint bad at all.

Your using 3/4" above the deck right? Just wondering wont that make the rear deck sit higher than the top edge of the back seat?

Sweet, that should add some nice bump to your metal.

10lbs aint bad at all.

Your using 3/4" above the deck right? Just wondering wont that make the rear deck sit higher than the top edge of the back seat?
No MDF on top of tray....the missing top piece not in that pic
Will go on it and entire unit goes in trunk only. Daniels design. I copied it.

Carriage bolts thru package tray to support it .
Custom package tray cover over it with premium vinyl.

Ahhh, gotcha.

Take plenty of pics for us!

Serious recommendation for you, Ace.

Go through, drill pilot holes and screw that beotch together. Liquid Nails is a much better adhesive (in all seams) for sub enclosers using MDF, but the screws should help out without it.

If you used silicone caulking, rip it all out and replace it with acrylic. The fumes for the silicone can deteriorate the adhesives which hold the sub together. Also, the silicone tends to lose its adhesion qualities on wood as time goes by, especially in extreme temperature changes like we get in IL. ;)

BTW, that looks like a good choice you made for a sub. That .50 cu/ft requirement is certainly a plus. I may have to consider that one for my wife's van.

She gotta swagger-wagon... yeaaaaahhhh.

2006 Pontiac Montana AWD. The movies just don't have the zip without the bass.

She gotta swagger-wagon... yeaaaaahhhh.



HAHAHAH I love that video!!

http://www.youtube.com/watch?v=ql-N3F1FhW4


Looks great Ace. I just might copy ya!!

How to design + build a sub box (http://www.youtube.com/watch?v=tYD_Fe9Lvv8&NR=1) - Soundman

How to carpet a sub box (http://www.youtube.com/watch?v=SHKOtUPKwME&feature=fvw) - Soundman

They used the brad nailer + glue like I did and caulked it afterwards as well.
The carpet install is a HUUUUGE help for doing the seams.

Okay, finally got some progress pics......

3/4" MDF sub box top piece, cut with router, and sanded down with table sander.
Thank God for my neighbor who loves to do woodworking.

http://i46.photobucket.com/albums/f122/Aceshigh22/Stereo%20Install/2010SubwooferInstall9.jpg

I had to cut the base width shorter by about 1.5" on both sides as well as ditch the lips. It wouldn't fit.
http://i46.photobucket.com/albums/f122/Aceshigh22/Stereo%20Install/CamaroSubBoxnearcompletion.jpg
Here it is after I cut the package tray with an angle grinder, put my sound deadener in, ground down the edges,
and taped them. Then I test installed the box. I have to pull it back out when my carpeting gets here....today or Monday.
http://i46.photobucket.com/albums/f122/Aceshigh22/Stereo%20Install/2010SubwooferInstall10.jpg

The package tray is another thing that I had to redo.
The OER crap doesn't last but 1-2 years out in the seasons in Chicago.
They curl up , for example this time I got a pic. This is my 1 season old brand new package tray in my 442.
I've killed a Mesh and Solid one in the Camaro, and now I've killed a Mesh and Solid one in my 442. I've gone
through 4 in total. :rolleyes:

It's ruined after only 1 year. Straight GARBAGE>
I'm doing a separate RE-writeup on how to make a better package tray.

http://i46.photobucket.com/albums/f122/Aceshigh22/Stereo%20Install/DSC02479.jpg

I just finished the layout of my new package tray out of hardboard.

Now I just gotta decide which 10" subwoofer grill to buy
......unfortunately I can't find anything from Boston Acoustics to match the sub.

http://i46.photobucket.com/albums/f122/Aceshigh22/Stereo%20Install/DSC02480.jpg

Looking good bro!

looking very nice, i'm awaiting pics of how you bolt it up so I can follow suit.

Mounting it is a PITA because I have my rear window in. It has to be
done accurately, so you have to do it all from UNDER the package tray. ;)

My top board of my sub box had 3" overlap on both sides to use for mounting holes.
Then locating where I wanted to put the holes and drilling them in was a PITA too.
Word of advice......use a corded drill....I used my 18V cordless and it took longer. :screwup:

Crawling in and out of that trunk takes some serious acrobatic yoga positions.
I used my wife's white nail polish to mark the measurements. :crazy:

You can see the 4 carriage bolts on the package tray I used.
They were 5/16" x 2". I used one 3/8" washer in the recessed hole above. (Dr side rear)
I used big washers all under it with nylon lock nuts.

After I'm 100% completed, I'll probably delete this thread and start a "How to DIY" thread with all the pics.

Cool cant wait to see it.

After I'm 100% completed, I'll probably delete this thread and start a "How to DIY" thread with all the pics.

Very cool Ace, Im anxious to see a walkthrough on something like this!

Guess I forgot to update the thread with the final pic.
Top tray is overextended for support bolts to go through from the package tray.
Bottom tray is overextended to mount 2 amplifiers on it while suspended.

http://i46.photobucket.com/albums/f122/Aceshigh22/LS1%20Implant/2010CustomSubBox.jpg

end look

http://i46.photobucket.com/albums/f122/Aceshigh22/LS1%20Implant/Subboxintrunkview.jpg