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Discussion Starter · #1 ·
Hey all

Looking for some advice on sub placement. Really one of two places. In my last car I had a homemade box with two 8s. Initially I had them facing the front to protect the subs (I didn't have grills). At some point I turned them around so they faced the rear - and there was a substantial improvement in sound.

With the challenger, I really don't want them sitting in the trunk like that. Just in the way when I need to carry stuff. So the only other option is is those custom boxes that tuck into the wide spot on the trunk. I would make my own. My concern is that this placement will cause the performance to suffer. Also, since I already have the two 8s, I would want to reuse, which means one (potentially) on each side. Will the sound waves offset each other?

Thoughts?
 

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Hey all

Looking for some advice on sub placement. Really one of two places. In my last car I had a homemade box with two 8s. Initially I had them facing the front to protect the subs (I didn't have grills). At some point I turned them around so they faced the rear - and there was a substantial improvement in sound.

With the challenger, I really don't want them sitting in the trunk like that. Just in the way when I need to carry stuff. So the only other option is is those custom boxes that tuck into the wide spot on the trunk. I would make my own. My concern is that this placement will cause the performance to suffer. Also, since I already have the two 8s, I would want to reuse, which means one (potentially) on each side. Will the sound waves offset each other?

Thoughts?
Depending on what subs you have would determine the size of the enclosure. Probably the best bet would be to build a box up against the back seat and fire to the rear. You could build two fiberglass boxes in each rear corner but they would be different sizes and they need to be in the proper air space. The corners are different. If it were me and wanting as much trunk space as I could get and still have good sub, I would opt for the JL prebuilt made for the drivers side corner in the trunk. Going to set you back $700ish but it drops right in and you are done! Still have all your trunk space. It really isn't worth all the trouble unless you are really going for all out. The prebuilt from JL isn't going to win any bass drags but it's more than enough for most. It's a great option for the DIY person. If you want to build one for the drivers you have, post up what you got and I will take a look at them.

Brad
 

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Discussion Starter · #3 ·
Thanks for the response. Output wise, the two I had were enough. 500w rms amp. I have the six speaker alpine, so the plan is to replace all six speakers with something in the $80-100 per set price range, then get the PAC amp interface. I have a four channel amp for the larger speakers, front corners will not be amplified, will just get soemthign with a high sensitivity. I certainly don't need to win any sql competitions, just loud and clean on occasion.

After buying the car, the $600+ I referenced above will be a tough sell for the wife. Another $700 for the box just isn't feasible at this point. But would be preferred if cost wasn't an issue. I'll probably just do what I did before and make the box easy to remove when needed.

Unfortunately I don't know anything about building with fiber glass, all I have is that particle board (drawing a blank on the acronym) to work with.
 

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What is the make and model of the subs you have. I will see if I can draw up a box for ya. You ok with some wood working?
 

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The Bacon Hauler (‘12 Cop Charger)
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There are way too many variables for anyone to be able to tell you what the best setup for your two 8” subs will be. You will have to do some experimenting and decide for yourself.

However, there are some general things that can be kept in mind to guide which orientations to test first so you don’t waste time on configurations unlikely to yield satisfactory results.

1) the back seat will absorb a lot of the subs’ output before it gets to the front of the car to be heard/felt.

2) sub placement and orientation in the trunk will greatly affect the perceived output at the driver’s seat.

3) unless they are some ultra-high quality, really expensive subs, and enclosed in a well made box built to specs specifically for them, you will struggle to get satisfactory results from two 8” subs in the trunk of a Challenger.

In other words, based on my experiences trying to add some bass to these Dodge cars and on the info you’ve given so far, I think you will need to get everything with respects to the subs’ box, its placement, and its orientation just right if you want to make two 8” subs work in your trunk.

Here are a couple things I would say to keep in mind:

- Placing a sub box against the back seat and facing it backward can yield up to a 3 dB increase in perceived output thanks to the cabin gain of the trunk.

- you should amp the hell out of the subs; the more, the better; if you don’t exceed the subs’ recommended RMS wattage by at least a bit, you’re making it harder to succeed here.

- prefer a ported box over sealed for this application; and if you do go sealed, you better amp the subs @150% their recommended RMS if you hope to succeed here.

- the side panel placement you mention can work, but it means starting out at a disadvantage, so you better come with a LOT of amp to get it done.

- facing two subs at each other can work if you have their phase correct, either on the amp or by switching the speaker wires feeding the subs.

- having plenty of high-quality, correctly crossed-over midbase will help strengthen the bass from the subs. Adding a good sub setup to an otherwise crappy system with little to no midbase picking up where the subs’ bass notes leave off will hurt the bass from the system a great deal.

If your rear seat back is in the 60/40 split bench style, pulling the passenger side (40 from 60/40) down to allow full access from trunk to cabin will significantly increase the bass notes’ intensity originating from inside the trunk.
 

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Discussion Starter · #6 ·
What is the make and model of the subs you have. I will see if I can draw up a box for ya. You ok with some wood working?
Looks like they are Kicker 44CWCS84.

I can do some woodworking for sure but certainly not a master carpenter. I built the current box but it's as basic as it gets.
 

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Looks like you are going to need around 1.2 ft3 per driver. Not sure what to tune it to, probably around 38ish so each side will be a little bigger to make up for the port. I wouldn't do sealed as output will be reduced. Sealed will have a smoother roll off but you will be happier with a ported enclosure. Especially in a trunk. That is a good size box by today's standards. Best bet for that would to build a box with an angled front that matches the seat angle and slide it up against the seat. place the drivers on the back side facing towards the rear of the car. I would remove the factory sub to allow some air to enter the cabin. Not much else you can really do with what you have.

What do you have for power? A good rule of thumb would to have about 1.5 times the RMS of the speaker to allow for headroom as long as it is clean power. Can't really have enough power or too much for that matter. You could go a little bigger on the enclosure to give you a little more output on the bottom end but power handling will suffer. The trunk also is an enclosure that will react to what you build. There is a science to this. Keep in-mind, you will do more damage to a speaker under powering it than over.

Building off of what Nuke stated, he is exactly right. You need to also plane on replacing the door drivers with a good set of 6x9's. Really just midbass drivers. I would also seal up the doors with sound deadening. This will build in the mid bass department that will greatly help with the sub department and pull the sound stage towards the front which you want. The doors should have a good response from say 60hz to about 500hz. The dash should run up from there.There are many post about this if you do a search.

It's going to be a little tricky building this enclosure as the port is going to kinda long. Not sure on the total length yet as I haven't run it in the software yet. Not sure about your woodworking skills are or what tools you have so maybe a sealed at 1.2 per side may fit your situation better. There are much better options out there when funds permit other than these 8" Kickers but you have to work with what you got. I fully understand running it past the wife. I was lucky, I made mine agree before she signed that she had no say with my audio issues. The rest of the house she has full range on but not when it comes to the A/V gear. With in reason!
 

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Discussion Starter · #8 ·
Well to be honest, I've never put this much planning into my systems. And of course the sound quality reflected that.

I've always done sealed for simplicity and size. Generally what I remember was to go ported it would result in a much larger box.

My wife doesn't care about the stereo ; it's the dollar figure attached to the planned upgrades she objects to.

My amp is a mono Kenwood, rated at 500w rms. They were single voice coil and I wired them to give a 2ohm load to the amp.

I just measured my old box - it's pretty small. Again, trying to save space. Looking like about half cubic foot per sub, the bottom recommended spec. So I'll have to measure up and see how much space I can reasonably use in the trunk.
 

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The Bacon Hauler (‘12 Cop Charger)
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Well to be honest, I've never put this much planning into my systems. And of course the sound quality reflected that.

I've always done sealed for simplicity and size. Generally what I remember was to go ported it would result in a much larger box.
I, along with many others here, found myself in this exact same situation at some point in the past. Nothing wrong with being in this situation, but realizing its limitations and then working to overcome them is the main thing to work toward.

My wife doesn't care about the stereo ; it's the dollar figure attached to the planned upgrades she objects to.
Much like trying to make the SXT as fast as an R/T, it can get real expensive really quick trying to make a couple of 8" Kicker subs in a sealed box sound as good as a JL Audio 10" in a vented enclosure (for example). And what's worse, there more ways to mess it up than there are to succeed in such ventures.

There are 2 ways to proceed:

1) continue down the current path with the current hardware, spending money wisely and choosing as high quality products as possible, and doing as much of the labor as possible to fabricate anything that it's possible to fabricate.

2) punt from this drive and sell the current hardware for what you can get for it, buy (used) better hardware and start from there making it sound good.

#1 will be more financially agreeable, but it will be difficult to achieve the sound from the resulting system that you likely want to have at the end.

#2 will be less palatable, financially speaking, but you should have a much easier route to getting the quality of sound you are looking to end up with.

I've taken both approaches, relatively recently I might add, and I cannot say one way is demonstrably better than the other. It's all about managing expectations really. Just like with the SXT to R/T quest, you have to keep in mind what the possible results are of any upgrade in hardware, and do not take any long shot gambles or reckless experiments with unknown/unproven hardware.

For #1 to work, you will have to build a vented enclosure, and you'll need to do a very good job of it. That means lots and lots of math beforehand to come up with a cut-sheet that leaves nothing to chance. In fact, and I am serious here, I would suggest buying a couple 2'x4' sheets of OSB and just building some practice boxes to get the hang of it first before attempting the final build.

There are lots of little things about building a good, solid vented enclosure that you won't know, and no one can tell you, but need to be done if the box is going to be a success. Practice makes perfect here, and experience matters. That's why I suggest the practice boxes - that's the only way to learn what to do and what not to do when you have to have a 27" long port but the box is only 23" wide at its longest dimension.

I'm not just whistling Dixie either. I build sub enclosures about as well as I fly airplanes...which is to say, not very well. At least I didn't use to (build boxes), but now that i've got a few under my belt, most of which were ugly failures, I know what i'm doing to some extent.

My last enclosure I built was one which was meant to house my JL Audio 10W3v3-4, and I built it to JL Audio's published specs...kinda. Their specs wouldn't fit in the trunk of my Charger, so I had to modify the dimensions a little. I maintained the spec'd volume and port area though, and while it took me a lot of time and energy, I managed to build a box which has that sub rocking and rolling like i didn't expect. It's ugly as sin, but it works and works very well.

It's the 5th box I have put that sub in by the way, and the 2nd one I've built. I built a sealed one and then tried several pre-fab ported ones, all sounding better than the last, but none compare to this one I built to specs. Not even close.

My amp is a mono Kenwood, rated at 500w rms. They were single voice coil and I wired them to give a 2ohm load to the amp.

I just measured my old box - it's pretty small. Again, trying to save space. Looking like about half cubic foot per sub, the bottom recommended spec. So I'll have to measure up and see how much space I can reasonably use in the trunk.
There is no replacement for displacement, just keep that in mind. It holds true for engines and amplifiers. I'm not saying you should buy a bigger amp. You need to provide enough power to the sub to keep it in its butter range, and the amp should not be maxed out all the time on a 13.8v charging system either (advertised wattages will be for 14.4v usually; that's an important and sneaky discrepancy to keep in mind if shopping amps).

Finally, keep an eye out for used equipment. Folks who are upgrading to bigger and better things are going to sell their older and less grand stuff, hopefully at a steep discount. But their older and less grand stuff may be just what you're looking for, and that goes toward both #1 and #2 above.

Nuke
 

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This is much the same as the debate of supercharging the 392 or just get the Hellcat. Some want the joy of building and some just want the end goal. Both will cost you about the same in the long run. If you want to build, there is a learning curve with a bunch of trial and error but that's part of the joy. If you just want the end goal without all the trouble, buy quality prebuilt subs. Building will allow for more customized to your wants and needs where prebuilt will be more one size fits all. You need to figure out what those wants and needs are and figure out what financially you can apply to those wants and needs.

To build off of what Nuke said, I will give you a recommendation on to a good starter sub that would work with the amp you have and would sound way better than what you will get out of those Kickers you have. By the time you figure in the materials you will be half way to the cost of this enclosure and it will not perform close to this one. I have used just about every brand out there over the three decades I have been in audio and can honestly tell you that JL is one of those brands that don't BS. Some will say they are over priced but you get what you pay for. For the DIY person, it truly is the best bang for the buck. This sub is their budget lower power line but still will sound great. It is a lighter driver which only means lower power which is what you have. Remember, you need to match the driver to the amp. This is a finished box at $200! Sell the Kickers to a kid down the street that is just starting out for $50 and you are only out $50-$75 if you figure in the materials to build one for the Kickers and this one is about half the size. I'm sure the end table, coffee table, towels, painting, carpets, whatnot that mamma has bought was more than the $200 the JL cost. Just saying. Not trying to start any wars here but a man needs good tunes! And more HP!!! Just understand, it will NEVER be enough so start a fund for upgrades. It's a rabbit hole!

CP110-W0v3
 
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