FungsterRacing

iTrader: (4)

So I was intending on putting two 10" subs in the 8 with the corner mounted boxes, but I think I am going to instead put one inbetween the twl back seats. Ive seen it done and it looks clean, so I am just asking for peoples opinions on what make/model of sub you can suggest. Ive considered CVT shallow mounts, etc. I think only an 8" will fit, but Im not wanting a system that will blow my car apart, just add some nice low's and kicks.

If you have experience with a good one, let me know. Thanks!

firebirdude

iTrader: (3)

An 8" is definitely the largest sub that will fit in that location. Secondly, you do realize you must still build a box on the back-end of the pass through correct? And similarly, depth should not be an issue. So no real reason to use a shallow mount sub. I know a few people have used JL W0's there (no longer made, now W1's). The Alpine Type-R would be a fantastic choice, as it's always been known to do well in small enclosures, and my modeling software would agree. Other than those.... Arc, Image Dynamics, Diamond, RE, Sundown ....and Polk probably makes one.

Also, odds are you'll be using a single subwoofer? So be sure to look for dual 4 ohm or single 2 ohm voice coils. (Which I think JL no longer makes in the 8" size)

Lastly, not sure if this has been done, but you might think about using two 6" subwoofers in that location. Like the JL 6w3v3 or the CDT CL-6M. Not sure if you'll get more output that way... but it may just come down to looks/personal preference. Just a thought.

FungsterRacing

iTrader: (4)

I wasn't considering shallow mount, just keeping it open as an option. And YES, Type-R is what I was initially thinking! I have owned Type-R, Type-X, Type-S, etc. and I have loved all of them. I found they are very flexible per enclosure-wise.

I will be custom making a fibreglass box directly onto the stock shell most likely. I am also wanting to try to hit a single 2 ohm instead of the 4. I was considering two 6"s, but I would rather a nice single, clean hit rather than 2.

Thanks for the suggestions firebird, I knew you'd be lurking around this section of the forum

firebirdude

iTrader: (3)

Sounds like you've made up your mind. Good luck and post up pics when you're done.

FungsterRacing

iTrader: (4)

Actually I gotta ask something firebird. You seem to be an expert on this section of the forum. Now I have hooked up dozens of systems in my time, but I am now wondering what you figure I should be getting - a 4 ohm or 2 ohm? I plan on running it on a mono block amp. This would suggest I would use a 4 ohm sub, correct? I want the most power pushing out of it, obviously.

RX8Soldier

iTrader: (24)

I've been thinking about doing this for a long time.
However, time and priority have shuffled it back. I have a 10" sub in the trunk for now. Ugly, but does the job

If you get around to doing this, you should make a DIY. I know that there has been some interest in this...

Good luck!

firebirdude

iTrader: (3)

Amplifiers output more power with a lower impedance. So ideally, you want the lowest possible impedance your amplifier can handle without kicking into thermal or current protection. This is the rule of thumb and only maybe 1% of amplifiers over look this rule and output the same power at all impedances (JL HD and Slash series, Alpine PDX series, maybe a couple more...). This is done supposedly to allow more flexibility to the end user. But I don't see myself switching out subs every other week and having to worry about running a 4 ohm versus 2 ohm load all the time. 99.9% of users buy their setup and then leave it that way for quite awhile. Even if they upgrade later, just buy subs that give you a 2 ohm load. Manufacturers have gone out of their way to make this easy for us. But I digress....

What's the model number of the amp? Any monoblock amp is going to be stable down to 2 ohms, but some down to 1 ohm. I recommend using the lowest impedance your amp is stable to give you the most power out. Check your owners manual or online if you're unsure.

Telek

I too am very interested in this. Are you talking about putting them in the little removable section that opens into the trunk between the back seats?

I'd think that 2x6" would give more overall output than a single 8", no? 300W for the suggested Type-R 8" and I see 6" decent ones at about 200W each.

Not to hijack but does anyone know of pre-built enclosures that would work in that opening with minimal modification?

firebirdude

iTrader: (3)

There are none. No way.

The power rating between them is meaningless. You would need to calculate the amount of piston area (sd) by the amount of piston travel (Xmax). The problem being that different drivers will act differently in a given enclosure. Some enclosure designs may not even allow the driver to reach full Xmax, while it's rather easy with others. You would need some modeling software. Really not impossible, but just too much time involved for what is surely very little (probably not even noticeable) difference.

Upon thinking about it a little more, I decided to look up the specs on the JL W3's.

6W3v3:
sd = 17.36 in^2
Xmax = 0.35 in^2

8W3v3:
sd = 32.02 in^2
Xmax = 0.375 in^2

So as you can see, two 6W3v3's do have more surface area than one 8W3v3. But the 8W3v3 has a touch more travel. At any rate, the differences are far too small to worry about. Like I first said, it all comes down to looks. Some people might be smitten by having two small subs back there bumping away. I will also mention that the resonant frequency (Fs) of the 8" is a decent bit lower than that of the 6". Normally I wouldn't sweat it. But when we're talking about drivers of this small size, those Fs ratings start to climb rapidly. The 6" is ~42Hz and although this doesn't directly correlate against what kind of output you should expect at a given frequency, it does play a role in it. Getting to be a little high to be called a "sub"woofer.

Tamas

iTrader: (1)

Probably even the 8" is going to have a hard time to give you a good botttom end fill, unless you can come up with a great box for an excellent woofer. I think that's not easy with the space constraint you'll have when the box is in the passthrough, but I'm not an expert, so this is obviously just a hunch.

I think it's much easier and more rewarding to go with a 10" sub in the trunk instead. If you have money, the 4080 enclosure is excellent, but the ZEnclosures boxes are great and really cheap if you want to save money.

Telek

So a 10" sub in the trunk despite having to pump through the seats will give better output than an 8" mounted in between the seats pumping directly into the cabin?

firebirdude

iTrader: (3)

Meh. Tough to say. Way too many variables.

I don't know what it is about that pass-through panel that people look at it and instantly think "Oh that would be a good place for a subwoofer." But it must be just me. Because it's a very popular idea on this message board. So like I always say, to each their own. It'll work out fine. I just find it a little odd.

Fungster, I would recommend making the enclosure behind the panel as large as you can. With sealed enclosures, it's nearly impossible to go too large. Larger enclosures yield greater low frequency extension and increased driver efficiency. The difference between 0.6cuft and 0.8cuft could make quite the difference.

HiFlite999

iTrader: (2)

I know the passthru thing has been done before, as in this thread:

https://www.rx8club.com/rx-8-parts-sale-wanted-44/fs-custom-speakers-between-rear-seat-181487/

If you have the spare tire, space for an enclosure will be limited.

One thing I did with my sub install in the trunk, was to take out the plastic covers behind rear seats. There's no way to know, but I think it helps sound transmission from back to front. (Road and exhaust noise might increase too, but I knocked that down with Second Skin (Dynamat) in the trunk and seat area.

firebirdude

iTrader: (3)

They're coaxils!

HiFlite999

iTrader: (2)

Oops, wasn't paying attention to the type, just the mounting scheme.

firebirdude

iTrader: (3)

I know. Just shocked someone would go through all that trouble to mount a pair of coaxils in there.

In fact, if you read through the thread, BOOSTD7 comments on that and someone responds saying the speakers in the rear deck are too hard to replace. Is he driving the same car I am???

Tamas

iTrader: (1)

I used to have an 8" sub in the passthrough as well, but my box was obviously too small for the woofer to go deep enough. It just wasn't sufficient and I'm far from being a bass junkie.

firebirdude

iTrader: (3)

Any pics? Can you give us a ballpark on airspace after woofer displacement?

Tamas

iTrader: (1)

https://www.rx8club.com/series-i-interior-audio-electronics-24/installed-custom-stealth-sub-box-between-rear-seats-mp3-player-amp-38560/

Don't know the airspace because this wasn't done by me, but as I said, it should have been bigger for sure.

firebirdude

iTrader: (3)

Hmmm looks larger than I would have imagined actually. Nice system though. How are you liking the Polyglass line? Ever heard the K2's? I like them better than the Utopia's on most tracks.

Fungster, you might think about making the box run all the way across the back of the seats. That should give you a lot of extra room. Also, maybe use 1/2" MDF instead of 3/4" MDF?

Was the idea behind this design to allow it to be unsnapped and removed easily? Or just for looks up front?

Tamas

iTrader: (1)

The box was pretty, no doubt about it - but it was just not sufficient for my taste, neither in power nor depth. Perhaps if the enclosure would have been bigger (or maybe ported), it'd have worked better, but honestly, I'm not an expert, so I wouldn't know.
I still have everything the same way right now minus the subwoofer - it was replaced with a 10" Infinity Kappa Perfect sub in a 4080 box. This gives me what I was after. Not too much bass, but enough to make the system sound really good (at least good enough for me )

I like the Polyglass speakers. I heard about the K2's but don't have experience with them.

The reason for the design were both of the things you mentioned... but looks probably played more of a role. That, and the fact that at the time, there were no good custom sub enclosures available for the 8. Both the 4080 and the ZEnclosures boxes came to market way after my system was installed.

FungsterRacing

iTrader: (4)

I was thinking 1/2" for sure, but thanks for suggesting before I ask

I'm not sure whether or not that last question was directed towards myself, but I am hoping for a permanent install. As much as I love my bass, I don't want to overkill with this car. Not that I believe that this car will, as my father would put it, "Fall Apart", but I don't have the need for it.

On the other hand, getting two 10" subs in the trunk would be great, but I really feel the need to put something in that passthrough... so many possibilities

Telek

Hey Fungster I am on the same page - I had a mustang with 2x10+12 and it was CRAZY but my ears will never be the same I'd love to have some additional bass here but I certainly don't need anything crazy. The passthrough area looks like an ideal place to put something at the very least to allow a smaller unit to actually provide bass into the cabin instead of losing most of it into the trunk.

However my trunk is small enough as it is and is usually full so I don't want to lose much space their either - again making the passthrough probably an ideal area.

HiFlite999

iTrader: (2)

One concern is that the wavelength of low bass is quite long, around 22 feet at 50 Hz. To avoid interference effects, one would want the bass source to be further away than that, which is clearly impossible to achieve within a car. However, sticking it in the middle of the car, rather than a back corner of the trunk, halves the distance available and doubles the minimum lower frequency limit for which hearing "clear" non-bounced tones are possible. One also loses the corner-effects one could potentially get for corner-mounted enclosures such as the 4080. I have no idea if these thoughts matter much in real-life though. If one chose to go with a passthru mount though, I'd figure out a way to screw the enclosure securely to the floor to avoid weird rattles from the flimsy plastic pieces behind the seats.

firebirdude

iTrader: (3)

It would be more around the quarter wavelength. Regardless, the SPL guys are really the only ones that worry about that. For the rest of us, it's simply not feasible to design the entire car around mounting a subwoofer. Automobiles are a terrible environment for audio reproduction. We do what we can.

As for corner-loading, I've heard (and experienced) the rumors. But never actually seen any hard proof. I will admit though, that I've heard corner setups in several vehicles that impressed me compared to a more traditional position. I guess you could call me a believer.