Boot installs

[yetphoenix]

I run 15" custom sub box that use very little space . the face of the sub box runs along side of the inside of the wheel arch ,the back of the sub box is the same contour as the inside 1/4 panel .

tony

[Adie]

My amp for for my sub is in one of the trays in the boot under the floor, it's been there for well over a year now with no problems

[thehedgepig]

This is mine....
http://www.clubvr4.com/forum/vbpicga...p?do=big&p=969

http://www.clubvr4.com/forum/vbpicga...p?do=big&p=970

[pitslayer]

Issues? Getting the bass into the cabin would appear to require some ducting, as the seal between the boot floor and the cabin is pretty good. I was considering running some long, tuned ducts under the rear passenger seat? Wide and flat is the way LOL.

but, base isnt directional


Me personally untill i get around to doing it, 6 channel kicker in the black tray under boot floor, amp all the components in the car, subs not sure, got an 8" I want to utilise somewhere, also got 3 infinty 12" subs, one kicker 12" sub, and a 10" kicker sub, its all a matter of choice of what to use and where to put, got a feeling the 8" will be in the front somewhere

[Turbo_Steve]

but, base isnt directional

Actually, that's an urban myth. Bass is LESS directional than higher frequencies, but you can still discern low frequency positioning left to right. It's much (much much) harder to build a stereo image at these frequencies, however, hence the extensive use of mono: at such long frequency lengths, any stereo image would be at best muddled.

And despite any directional component, Kyle, if the speaker is mounted under the boot floor, with no airflow between the underfloor space and the cabin, you WILL reducing the amount of bass the sub produces: it'll be in a sealed box: how will the sound pressure waves get to your ears through the floor of the car?

Hence the need for ducting: your ears should always share the same pressure space as at least one side of the cone. Restricting this in anyway (i.e. my ducting) is creating an isobaric or folded port enclosure, which requires a lot of maths to tune correctly (however can result in massive output at specific frequencies).

In the same way, the front and rear of the subwoofer need to be as isolated from each other as possible UNLESS you have done sufficient calculation to fit a port or vent or passive radiator which will turn the rear-facing, out of phase waveforms by 180degrees and fire them forward, whilst not significantly adjusting their phasing.

Speaker design is hard.

Unless you build a suitable (and strong) box for your 8", it's never going to work properly, or rip itself to pieces.

I would respectfully suggest you mount it in the armrest aperture of your rear seat, facing into the cabin. Either that, or fabricate new door-cards, and have an 8" in each front door, which would be fantastic.

Don't get too hung up on big speakers: although they will move more air, your car interior effectively rolls off the bass at 50Hz anyway: past this point, the wavelength is so long that you will only be getting fundamentals within the car.

For proof of this, sit in a car with a really big system. Listen.
Get out, and leave the door open. Walk about 5 metres away, and notice how much deeper the bass just got!!!!

[bigsed]

This is mine....
http://www.clubvr4.com/forum/vbpicga...p?do=big&p=969

http://www.clubvr4.com/forum/vbpicga...p?do=big&p=970

Thats nice and neat, just what I was hoping to be able to do, so thanks for sharing

[Turbo_Steve]

It's great, but if you get a fibreglass box made up, the subwoofer needn't take up so much boot space, as it will be recessed into the body.

Really wish I could find some pictures of this process.......VR4WAGN has the technique off pat, though! LOL

[mesobitchy]

if its a good all round use of the boot ya after try this install, iv got it in mine









the bolts are 10mm.

the end result is very good, light weight an easy to remove if needed.
there are 2 amps there, one is for the 12" sub an the other (in the side) runs all the squeekers an tweeters
there is an powercap i there as well, an that along with the amps are wired into the pc.
i dont tend to wanna take them out but if i have to then its a very easy an almost timeless job to do so.

[pitslayer]

And despite any directional component, Kyle, if the speaker is mounted under the boot floor, with no airflow between the underfloor space and the cabin, you WILL reducing the amount of bass the sub produces: it'll be in a sealed box: how will the sound pressure waves get to your ears through the floor of the car?

you make a valid point there

[mesobitchy]

bass is ment to be felt..... oooh how good it feels when it rummbles up your spine and through your body when it hits!

an you can still hear it

[pitslayer]

i always work on if you can hear it its not low enough

[Turbo_Steve]

oooh how good it feels when it rummbles up your spine and through your body when it hits!

Agreed, however, it isn't going to get there through the chassis of the car.
You can only just about feel the engine through the chassis, and that's throwing big lumps of metal around.

How much vibration do you think a piece of paper moving backward and forward (especially in free space) is actually going to make to the car? If the back and the front of the speaker are in the same space (i.e. not sealed from each other, at least for the most part) then:
1) your speaker isn't working efficiently. See how much sound you can make waving a 10" circle of cardboard around
2) your speaker will gradually destroy itself unless it's designed for free air use, or you're running it at much less than it's rated power
3) the reverse phase audio from the rear of the speaker will actually make it even quieter.

Bass that is "felt" actually relies on sound-pressure-waves causing oscialltions in the cavities inside your body: primarily in the air-space of your lungs, however also inside your stomach, and the fluid areas around your spine and bladder and head. It will also disturbs your hair.

The pressure differential between positive and negative wave fronts at 120dB should be sufficient to move a suspended piece of paper a good 10mm back and forth...and will do even more for your hair: a Car with a really good bass setup will have a ghostly hand ruffling your hair...slightly louder will have a phantom hand squeezing your heart and making you short of breath.

A little further will have your eyeballs vibrating, and even further can cause digestive problems and physical pain.

None of this can be achieved through the chassis of the car, unless you're prepared to mount vibrators directly to the chassis, and remove the cushioning from your seats: It's all down to air pressure, and more importantly the air pressure changing from positive to negative at specific frequencies.

You don't even need huge power to achieve this: just efficient air movement.


You will struggle to produce bass you can't hear inside the cabin of a car: as mentioned, there simply isn't enough space to produce a wavelength below 50Hz. You'll get some fundamentals at 45Hz, mainly from parts of the car vibrating as the air looks to escape.

In fact, the only way to get below 48Hz is generally to open a window...though this usually results in more 72Hz, and plenty of 48Hz outside the car.

I'm sorry I'm such a pedant about all this, but there is nothing as frustrating as people spending a small fortune on stereo that they then proceed to slag off because they haven't used it properly.

[Kenneth]

Sealed enclosures require different specifications not only in size, but also in the driver and potentiall the control circuitry. Yes you will lose some max dB capability, but if you size your driver and amp correctly this won't be an issue. (unless you want to enter a SPL comp or something)

While I am no audiophile, I built my own sub for home which included specifically selected drivers, hand built amplifiers and processor and custom designed sealed box.

The performance is different and the processor allows the driver to work efficiently down at really low frequencies and below resonance so long as the driver specs are adequate and the processor is configured for the driver.

Automotive drivers are generally designed to be usable in sealed boxes.

As for being directional... I suspect that a small driver run very hard to create the illusion of bass is probably one which you can locate directionally, however mine you can't during normal use. You cannot even tell it is operating until you turn it off.
I suspect on a more practical level that being able locate the direction of a sub is more to do with the size of the sub vs the size of the area it is operating. Big sub in small area = no chance.


To me bass is experienced as an effect, the volume or dB level isn't important so long as the drivers can move enough air so you can really feel it.
If this is the case for you, you need a big driver and an amp to run it. Whether or not you use a sealed box is really not the point.

oh, and mine has been equalised to run down to about 16Hz using a Linkwitz/Riely transform circuit.
It took me 2 years of research and work to get it all set up, but I am hugely happy with it

[Turbo_Steve]

Ken, you're 100% correct, however, you're talking about a sealed enclosure in the traditional sense (i.e. speaker mounted on one face of a box). This will always give the 'most musical' (i.e. best controlled) speaker dampening.

What I was getting at is that if you seal the speaker completely in the boot, (i.e. speaker completely inside a box, with nowhere for the air to get out at all) then it just won't work, which is what I was getting at.

In the same way, NOT sealing the speaker (unless you're tuning a port to it) will make it behave extremely erratically.

16Hz! I bet you don't get many spiders in your house.
What source are you using, as most digital sources HighPass at 20Hz anyway?
I know that 16Hz is the end of the slope, so is still relevant, but was curious as to whether you were a closet analogue fan?

[mesobitchy]

i know my clarion is FUBAR as it split in 2 places only cos it bounced its self outta its box yes it was held in with wood screws.

i love to know what it puts out even in its poor state of behoned repair.
wonderfull 1200wRMS 12" dule voice happy days,

iv had it in an open box, sealed box an now how it is in the boot. an it sounds the best how its paced, do need to get another soon, i got an infinity but its noway near as good as the clarion, so i might sell that one with its box, along with a twin 12" sub box....

i know i still have it in the car for time to come so maybe at one of the shows this year i can show it, if peeps wanna see it.... the ICE that is

[Kenneth]

Ah, I see. But the boot is not even remotely sealed, so this is never going to be an issue.

How is being sealed in the boot any different to the driver standing in free air or just being installed in a very small room?

Personally, I would have thought that in a sealed boot the sound quality would be crap, resonance would rattle the car (so everyone outside knows just how big your stereo is ) and make all the bolts undo.

At present the source is a digital amp. 16Hz was just because that was the easiest combination of components which fit the driver specifications and the size of the enclosure which is really a little on the large side. It has 2 12" drivers in it and is big enough to be used to seat 2 people when on its side.

Ken, you're 100% correct, however, you're talking about a sealed enclosure in the traditional sense (i.e. speaker mounted on one face of a box). This will always give the 'most musical' (i.e. best controlled) speaker dampening.

What I was getting at is that if you seal the speaker completely in the boot, (i.e. speaker completely inside a box, with nowhere for the air to get out at all) then it just won't work, which is what I was getting at.

In the same way, NOT sealing the speaker (unless you're tuning a port to it) will make it behave extremely erratically.

16Hz! I bet you don't get many spiders in your house.
What source are you using, as most digital sources HighPass at 20Hz anyway?
I know that 16Hz is the end of the slope, so is still relevant, but was curious as to whether you were a closet analogue fan?

[Turbo_Steve]

Okay, I'm obviously being vague enough for you to get your pedant bar in

But the boot is not even remotely sealed

I say sealed in a relative way: just to be clear we are talking about the spare wheel well, here, and it is sealed enough for the air to make parping horrid noises as it moves in and out, and, as you say, rattle and roll like a good-'un. I don't doubt that if you get the enclosure right under there, it'll even lift the access hatch up and down, so it's sealed (but not air-tight) compared to the main boot area.

How is being sealed in the boot any different to the driver standing in free air or just being installed in a very small room

Again, I think we're at cross purposes: we're talking wheel well (i.e. boot floor) not the boot area, which is effectively the main cabin on a legnum.

If it's in the wheel well, with the lid / access hatch down on top of it, then you're effectively installing the subwoofer in your downstairs toilet, shutting the door, and then going and sitting on the sofa in the lounge and listening out for it. Sure, you'll hear it....but how loud does it have to go?

At least in free air (so mounted in the car, but allowing the rearward phase and forward phases to interfere) you'd get a degree of extremely directional bass.


I think we're actually talking about the same thing from opposite ends again.

[dickytim]

I think we're actually talking about the same thing from opposite ends again.

that's the way it looks to me.

[Kenneth]

Okay, I'm obviously being vague enough for you to get your pedant bar in
.
.
.
I think we're actually talking about the same thing from opposite ends again.

Yep, I think you are right on both those counts. Sorry bloke, sometimes I over analyse things

Factory 8" (I think) sub in the Galant is sufficient for me

[Fully]

Sound system should be built for the music you listern to.

I like trance/heavy metal/Soul. I can fell my subs through the seat. Even more when trance is playing