12 replies to this topic

[Snowfruit]

Should I vent the parcel shelf or back seat if I am going to put my sub in the boot? I have heard/read arguments for and against. What are your opinions?
by the way I don't have any speaker holes in the parcel shelf and am not planning on fitting any speakers there. The only two holes that have always been there are a pair of oval shaped inch to inc and a half cut outs.

[THedooBZ]

yes i would definietly recommend this, if you do not the sound and pressure from the sub will have nowhere to go due to the mini having a metal bulkhead in the back.

originally all i did was remove the factory speakers from my shelf as i had new ones in the front, then where the old speakers where i reattached the grilles with evostik to keep it looking original so to speak.
if you dont have any speakers as standard then yes you can use the 2 small holes in the centre and use a small port to fill the hole in, something like this would work..

http://www.maplin.co...2&doy=22m2&QV=P

obviously you would need to measure the holes.
basically the bigger the hole the more sound can get into the cabin.
]
i currently have cut around half of my shelf out and made a new shelf from mdf with acoustic carpet on top, this means that all the pressure can be released which is handy for bigger subs, but using the original speakers holes or the holes in the centre of the shelf should be fine either way it is well worth doing or else you are wasting your time putting a sub in your boot.
the best way to check the difference is listen to a track of music that is quite bass heavy and then cut the holes and listen again, u should be able to tell the difference.

hope this helps.


sorry just re-read your post you dont have factory speakers, so just go with the option of porting the centre holes and you shoulkd be fine.

[philster]

you could aslo remove the little bits of foam at either side of the bulkhead where it meets the side panels.

I've heard minis with and without port holes and to be honest i wouldn't say either sound different.

It won't do it any harm putting them in though.

[binge]

I personally cant see how putting reflex tubes in the existing holes will produce more volume in the cabin. if anything it will just reduce it right?


Anyway, to be honest, Subs give off Non directional Sound, so wheather the boot is ported or not, you will still beable to hear/feel the bass in the cabin if the sub is in the boot.

I was running this setup...




It had a completely sealed off boot space because the speakers I had in the rear shelf were boxed in to seperate them from the sub.
Had a full boot board kit too, So basically when the boot was shut, the boot was sealed.


The bass IN the car was still Immence, and could go to stupid volumes. AND it was only a 10" sub running a 120watt rms amp. Not bad at all!

[Snowfruit]

OT a bit but binge, where dis you keep your spare tire with that setup?

[philster]

Think it was kept under the board (hence the reaseon i don't run a sub box in my boot). The space is certinaly there for it.

You don't need to use port tubes when venting the rear shelf either, holes would suffice but for the price of a couple of ports it will look a lot more professional.

[gsms]

I actually vented my parcel shelf today, and I did notice a fair bit of difference.

I covered the whole shelf with a layer of black fabric though, so no holes were actually visible.

If the holes would be visible, then definately go for the port tubes, just to make it look a bit smoother.

Guy.

[THedooBZ]

I personally cant see how putting reflex tubes in the existing holes will produce more volume in the cabin. if anything it will just reduce it right?

yes this would be true if the holes were visible, but if you have a parcel shelf they are not, thus exposing the holes would release pressure.
the ports are only for cosmetic purposes and of course will not change the sound itself.
obviously if you do not have a parcel shelf fitted then it wont make a blind difference

I actually vented my parcel shelf today, and I did notice a fair bit of difference.

cheers gsms, thanks for backing up my explanation, i first realised by accident when i removed my parcel shelf to retrim it.

[binge]

Well if you lot need to cut holes in your car so you can hear your sub from the cabbin then your amps Just cant be powerfull enough!

[nmt_oli]

Binge, porting really does help. in a completely sealed boot there is nowhere for the generates pressure to go. yes you will hear something, mostly due to the rearbuilkhead/shelf vibrating, transfering the bass into the cabin.

By porting int othe cabin, you directly allow the generated pressure/sound waves to enter the cabin, and there will be a difference, be that in volume or clarity or frequency heard in the cabin. The situation will be diff in every mini as you are effectively creating a bandpass enclosure - sealed box, sealed boot vented into cabin. this creates 3 chambers, with the driver in between 2 and the ports between the other two. if you calculated the volumes and port sizes and built it correctly, it would really KICK, it would be louder than the same sub directly in the cabin- this is a lot of work however.

i know bass is "non directional" in terms of our hearing, but if its in a sealed area, it will be quieter! Its lke boyracers with there badly installed subs, yes you can hear the bass outside of the car, but it will sound much louder, and more rounded inside!

Also, dont compare a mini to a typical hatchback- most people dont bother to vent those as theres no point, this is because the rear seats a folded back against the boot space and so the boot cavity is by no means sealed.

[nmt_oli]

I started off with a sub in a sealed enclosure in the boot. But this caused a bit of a pressure problem inside the boot, and caused my boot lid and floor to resonate making horrible rattle noises from the outside of the car.

Now im running an infinate baffle sub (free air) which is mounted in the center of my parcel shelf (meant cutting a 10" hole in my shelf)


<|ben|>

just found this in another thread! When you were running a sub in a sealed enclosure, you were having rattling problems as there was nowhere for the pressure created to go! its common sense. if you port, it has a similar effect (slightly different as your adding a 3rd chamber) as runnign the sub in the cabin, or a free air sub in the shelf which is effectively a sub in the cabin.

if you had actually tried porting, you would have noticed this!

not trying to dig, its just you seemed to say "it sounded great when sealed" earlier in this thread, but then make posts in another thread saying its not good.

[THedooBZ]

Well if you lot need to cut holes in your car so you can hear your sub from the cabbin then your amps Just cant be powerfull enough!

it surely isnt when my amp will run at around 800w rms @ 2ohms

but honestly i think it is just a matter of opinion, only after doing it myself did i realise how much of a difference it makes.
i mean it is a fact that if you put a sub in a sealed metal box you would produce hardly any sound and a hell of alot of resonance and rattling which is essentially what you do in the boot of a mini with it all being a metal bulkhead,my boot floor also used to rattle like hell, so i sound deadened it, but this didnt cure it all.
so then i ported it, once it was ported that was it, the rattles went.

if i put my stereo on full wack and close the door and stand outside there is hardly any sound due to the amount of sound deadening, open the door and it will rattle my garage door and the neighbours which are a few metres away, always puts a smile on my face!!!

QUOTE(binge @ Mar 3 2006, 01:37 AM) *


I started off with a sub in a sealed enclosure in the boot. But this caused a bit of a pressure problem inside the boot, and caused my boot lid and floor to resonate making horrible rattle noises from the outside of the car.

Now im running an infinate baffle sub (free air) which is mounted in the center of my parcel shelf (meant cutting a 10" hole in my shelf)


<|ben|>

well i think what binge means is he started with a normal sub in a sealed enclosure in the boot but with no venting from the boot so it sounded C**p, so now he is running freeair in the parcel shelf using the whole boot as an enclosure for the sub and it sounds good, thus proving that the boot must be relativley sealed as if it was not the sub would sound rubbish.
i have thought of going the freeair route before but have never found a sub which like as there are not many manufacturers which produce one. so for now ill be happy with my boot space taken up, but hey theres more room on the back seats for luggage anyway.

[philster]

If you take the little bits of sponge out from either side of the rear seat back then there should be plenty of flow for the pressure caused by the sub.

The mini boot space really isn't that well sealed from the cabin (you'd realise this if trying to fit a free-air sub properly).

I can't see the ports on the shelf doing it any harm, its certainly not gonna make it sound worse.

Porting the shelf with a free-air type install is a complete waste of time as the boot space is far bigger than the sub needs so porting would only make it worse.