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View Full Version : Anyone have a half wall/back seat install?



JohnBlayz142
01-31-2007, 06:53 PM
I've been contemplating removing my rear seat and doing a single 18 or a couple 15's ported in place of it. They would most likely be firing forward at the rear of my front seats. I have heard a couple installs similar to this in the past and they have been nice and loud.

I'm looking for pictures of installs like this or perhaps opinions from those who have done something similar. My car is a 2001 Acura CL type S, a coupe obviously. I do not want to run a full wall, as I have had them in the past and want my rear vision.

Thanks to anyone who can help.

kicker06
01-31-2007, 07:32 PM
In my car, sub and port forward is not as loud as sub back, port back.

But you could try it.

uhoh45
01-31-2007, 07:47 PM
http://i2.photobucket.com/albums/y31/uhoh_45/Speakers/wall.jpg

JohnBlayz142
01-31-2007, 08:01 PM
In my car, sub and port forward is not as loud as sub back, port back.

But you could try it.
I'm not talking about trunked setups. I fail to see how a half wall could fire back. Did you read my post?

JohnBlayz142
01-31-2007, 08:02 PM
http://i2.photobucket.com/albums/y31/uhoh_45/Speakers/wall.jpg
There's not too many other ways it could be constructed, but thanks.

PhatTonyDeMarco
01-31-2007, 08:06 PM
I had one in my '98 Buick Century, and could never get it louder than when the 18 was in the trunk...

It was deffinitly not worth losing the back seat.

JohnBlayz142
01-31-2007, 08:07 PM
I'm not concerned with the meter. I don't want the very rear portion of my car weighed down and I don't want ghetto trunk rattle which will be there no matter how much I deaden it.

The last setup like this I heard was a 13w7 in a mustang convertible and it blurred my vision pretty well.

Camineet
02-18-2007, 10:23 AM
I'm also starting a major project like this with a 92 Firebird convertible. Definitely need feedback and guidance. Let's get together and discuss it.

JohnBlayz142
02-18-2007, 11:16 AM
Unexpected bump....does anybody have any input that might not have seen this thread before? Thanks.

Camineet
02-18-2007, 12:18 PM
Hey John,

Just to get the ball rolling on this discussion, I'll tell you how I plan to try mine at least for the first try version.

I'm putting two tens and one eight on my wall, facing forward. In order to keep it simple and cheap and not time consuming and labor intensive, I plan to buy boxes on eBay for each woofer, and simply tack them to the back of the wall.

Unfortunately most ported boxes are ported in the same direction as the woofer faces. I'm quite sure that a port facing forward will have very little benefit. In my experiences, ports and preferably woofers must be facing something off which to reflect. Following this logic, a woofer facing the front is a sub-optimal configuration if housed in a simple box. I want to do this wall thing regardless for cosmetic reasons, and I will already have two twelves in the trunk. But as far as ports go, I would prefer to install them because I do like ported boxes. And they should certainly face downard I would say. However, porting a sealed box apparently requires quite a bit of science. I don't want to screw up the port job and end up with what I have heard called 'a leaky sealed box', or one with 'port noise'.

On another note, this whole wall thing with woofers facing the driver is getting popular as you mentioned. I went to a local car show here in Orlando and a number of vehicles had this configuration. Back then I was unfortunately not planning to do this, and did not get any information from the guys who did it. I would imagine however that the results must be strong as you mentioned, otherwise people wouldn't be doing it. But in order for it to be successful, I do think that a complicated all encompassing enclosure that basically turns the 2nd to last 1/4 of the vehicle into a speaker box is necessary. Oy, I'm just not up for that I don't think. Maybe on the 2nd try. I want to try my simple version first. Hopefully 2 twelves in the trunk, 2 tens and 1 eight on the simple wall will be enough to satisfy the first time. I just don't have $1000 to throw at the local shop to design some kind of super custom scientific box for my vehicle right now.

Well, that's where I'm at thus far. Right now I'm going to go out to the local auto parts store and stand around for a whole fvcking afternoon so I can get a couple of bolts to put my front seats back in (car is gutted, has been sound deadened extensively) and see where exactly this wall will fit into the vehicle in relation to the front seats fully reclined.

ngsm13
02-18-2007, 12:21 PM
Don't do it.

nG

Camineet
02-18-2007, 12:24 PM
Don't do what?

I'm already putting a wall up just because I have so many electronics, that the back seats have to come out no matter what. I have a WinXP PC, two amps, two caps, distribution, and crossover, and two 6x9's. They're all going on the wall. Then once it was determined that the back seats must come out, I figured I might as well add a few more woofers since I have a few extra amps.

So again, don't do what?

Mitch86
02-18-2007, 12:29 PM
69's in the WALL YO.

mikey060
02-18-2007, 12:35 PM
Don't do what?

I'm already putting a wall up just because I have so many electronics, that the back seats have to come out no matter what. I have a WinXP PC, two amps, two caps, distribution, and crossover, and two 6x9's. They're all going on the wall. Then once it was determined that the back seats must come out, I figured I might as well add a few more woofers since I have a few extra amps.

So again, don't do what?

:laugh: how many different sub sizes are you using? and let me guess..they are all going in a common chamber arent they

ngsm13
02-18-2007, 12:43 PM
1. I wasn't talking to you.
2. I was talking to the OP.
3. Still, don't do it.
4. Yeah.

nG

uhoh45
02-18-2007, 03:31 PM
http://i2.photobucket.com/albums/y31/uhoh_45/Speakers/wall.jpg

this is for half wall half trunk

Camineet
02-18-2007, 03:51 PM
Thanks a lot for the guidance. This particular box wouldn't work for my convertible, but it is a good reference from which to start considering such a box configuration. My convertible sits so low, that this box upside down might actually work. You see, just behind the rear seats is a steel wall. And just behind that wall are the actual rear wheels. This is a low SOB. This box upside down would allow for the back part to extend into the trunk space. After getting over the wheels, the trunk does dip down to the street quite a bit, and this box wouldn't take advantage of any of that space. In fact, the back part that extends rearward into the trunk would be awfully thin if I were to flip this box and try to implement it in my vehicle.

Hey what the heck am I thinking? The part that would extend toward the trunk would be the spot where the convertible top goes. Nevermind. Back to the drawing board. I think my original idea of tacking on eBay boxes to the back of the wall is still the only way for this vehicle.

theCybe
02-18-2007, 05:08 PM
Hopefully 2 twelves in the trunk, 2 tens and 1 eight on the simple wall will be enough to satisfy the first time. I just don't have $1000 to throw at the local shop to design some kind of super custom scientific box for my vehicle right now.

We're all going to tell you that it's wrong to do this, but you aren't going to listen.

Lots of super-scientific box plans available for free in the sticky thread at the top of the enclosure design subforum.

Camineet
02-18-2007, 05:16 PM
Do you mean that there are box plans in the sticky thread that will work well for this type of enclosure? I'd certainly be interested in checking them out. I'll have a look at that thread.

You're the 2nd responder who has advised against doing this, but nobody has yet to explain why I shouldn't. I have seen this done in at least three vehicles before, so I have reason to believe that it can work. Plus the OP said he heard a convertible Mustang with this type of enclosure that was awesome. So I would very much appreciate it if someone would shed some light on this apparent pitfall that I'm supposedly headed toward.

inapontiac
02-18-2007, 05:24 PM
keep the back seat and do like i did

http://img413.imageshack.us/img413/5064/1001352ix9.jpg

http://img458.imageshack.us/img458/2255/1001359ey6.jpg

JohnBlayz142
02-18-2007, 05:32 PM
1. I wasn't talking to you.
2. I was talking to the OP.
3. Still, don't do it.
4. Yeah.

nG

I've heard systems like this that have sounded great....why wouldn't you do this?

And InaPontiac, I don't want do do all that sealing work. I just got my car and I'd like to keep it in factory like condition.

theCybe
02-18-2007, 05:39 PM
Since have good manners and a grasp on the English language, I'll be happy to advise you as to why mixing subwoofer sizes will yeild dissatisfactory results.



When a woofer moves, it creates a soundwave by affecting the air around it. Air is compressed, and then rarefied. These waves travel at a particular velocity.



When you combine these waves with waves from additional devices on different trajectories, you experience a collision of waves, resulting in 'cancellation.'



A driver in your trunk produces a wave. That wave arrives milliseconds later at nearly the same point as another driver that is producing the wave - the delays (sonic, electrical, and mechanical) between waves being produced makes them 'out of phase' - reinforcing one part of the wave, and cancelling another part.



Which leaves you with poor sound quality and less than optimal performance.



Woofers of different sizes have different performance metrics, and although a 30hz electrical wave looks the same on the graph, what comes out of any different speaker, at any different position, from any different enclosure, of any different size, reflecting off any number of different surfaces at different distances -- you get the idea. They just don't match up.



:)



Choose a size, choose a plane, and install your woofers on the same plane.


Mixing them can be done properly in theory, but the mechanics and calculations involved are enough to drive a sane man mad.

Camineet
02-18-2007, 06:05 PM
I agree with everything you said. I've operated under those same principles when designing all of my past systems. But this time around you may have been right when you said that no matter what I'm told, I'm going to still try this. Here's why I'm still optimistic. In recent years I've seen some really wacked out installations. I've seen numerous fiberglass fabricated boxes with woofers facing all different directions as if they was some kind of snapshot of a cluster of woofers exploding taken. None of them are on the same plane, and some of the darned things are even facing inwards into the box with the others conventionally mounted firing outwards. Plus, I've seen doors, sail panels, rear decks, trunks. etc. lined with multiple woofer sizes in these next gen installations. I figured that people had discovered that by throwing out conventional thinking and just going nuts, that they were achieving great results.

I'll be honest, if I really thought I could get 100% satisfying results with the two twelves I already have to put in the trunk, I would probably not bother with trying to add more woofers. But since the convertible trunk is so small, it just won't accomodate a large ported box. A sealed box is all that will fit. I'm just not confident that this will get her done. So I'd like to try some experimentation with this wall thing, especially if others have succeeded.

The other thing is, I love the appearance of Polk Momo woofers. These are the twelves I started with. Then I realized that I had another amp that could power an 8 inch woofer, and that I'd just love to see one of those Momo's in the passenger compartment rather than having to open my trunk to see the twelves. I envisioned it as being positioned similar to the Dodge Viper 8 inch woofer in the same place (at least the early models had this I recall). Then I realized that I have yet another amp that can power two tens, and I could toss those on the wall as well and still fit my carPC, the original two amps with which I started the design, distribution, crossover, caps, and 6x9's. So this isn't entirely for achieving crazy SPL. I want to put these woofers in a visible place for cosmetic reasons, and I'd like to implement a decently efficient design in order to achieve enough bass to satisfy me. My reason for posting is in the pursuit of putting these things on the wall in a way that will hopefully achieve some echo chamber effect if it can be found at all in this configuration. If the only effect I get with these additional woofers is similar to the results of tossing a sealed or ported box into the backseats of a sedan, then I won't entirely regret it. If by turning off the wall woofers and just playing the twelves I get better results, then I will certainly not include them in the final installation.

Again, thanks for your guidance and patience. If in the end the twelves sound better alone, I will certainly know why after reading your response. Given that I will at least go forward with this as an experiment, any additional advice you have that moves me closer to a result that's better than the 'box in the back seat of a sedan' effect would be great. Thanks again.

Camineet
02-18-2007, 06:15 PM
Oh, one more quick thing. I remember now why I decided to go forward with this experiment in the first place. I did do a quick check to see if this wasn't totally erroneous. Here's how: When I first thought of throwing in the eight incher, I first recalled what I knew about cancellation. Then I immediately recalled all of the wacked out installs that I had recently seen. Then I recalled something from personal installation experience. My first system started off with two Kicker tens. Then I added two fifteens. This was in highschool before I knew better. Well, I recall hearing about cancellation and checking my highschool system back then to see if I was indeed wasting gas and electricity by hauling all 4 of those different sized woofers around. Nope, I listened to them separately and together. That system was definately as incrementally loud as each set of woofers were alone, when combined. Does that make sense? In other words, I ran them independently and together, and found that the system wasn't experiencing any noticeable cancellation. And the tens faced inwards from the sides of a Daytona hatchback with the fifteens in the farthest back facing the glass. If I had a big 'ole truck I would certainly follow plane, size, and wave principles. But this is a really limiting installation, and I gotta be bold. Thanks for your understanding, and hopefully your support.

theCybe
02-18-2007, 06:31 PM
I say go for it then, if you're aware of the implications.

Just a sideline regarding inverted subs; It's fine to do this, just reverse polarity on the inverted one. So mechanically, that's "less crazy" than multiple sizes, and crazy-pointing woofers. :)

Best of luck, and do keep us posted on your progress. :)

Camineet
02-18-2007, 07:02 PM
Right on thanks. I've started a new thread asking if there's anyone like Moe Lester who can design me a box for a fee. I wouldn't mind building one like he has posted, but the ports are all front firing. So I asked the forum if there's someone who can use some software to design me one like Moe's, but with the vent on the bottom. I've seen little wedge boxes with the ports on the top, so although this may not normally be a great way to build boxes, I do know I've seen it before and can at least hopefully get me better results than a sealed box. We'll see.