langey
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Registered: 7th Sep 03
Location: Wigan
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am i just plain stupid or will/could this work.
2 12" subs mounted on the rear shelf? or 1?
and if it needed it, boxs built round them. 
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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hmm u CAN do it but i wouldnt. I had a single alpine 10" type-s sub in a shelf in a nova and it was heavy enough to break the side plastics and cause all kinda trouble. You would also need free air capable subs and to make sure the amp power closely matchs the subs.
Overall its NOT worth it, so dont do it !
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langey
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Registered: 7th Sep 03
Location: Wigan
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well i just wanted it to be louder and thought that was the way 4ward, or maybe i should have the subsfacing up, and not have a shelf?
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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if u want it louder getlonger excursion/bigger diameter subs or port the ones you have. I just wudnt reccomend a shelf.
U cud put sub horizontal, but dunno if it would make it any louder.
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baza31
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Registered: 19th Apr 03
Location: yorkshire
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jus make a box under the shelf. u wont be able to lift the shelf tho. js remove the shelf, and point the subs upwards if u reall want em pointing upwards.
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Dom
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Registered: 13th Sep 03
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i remember a french bird having a purple corsa, who had a 18" in the parcel shelf that was on hydrolics - lifted up to reveal amps underneath. Its was some crazy mofo shit 
But yea its possible - make the shelf outta thick mdf  want like 10mm (thicker the better!) and then wack on a air free sub on the bottom
But adi is right, if you get an air free sub, your gonna need an amp that pushing out the RMS wattage atleast to get the best outta it 
[Edited on 25-12-2003 by VisibleMan]
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langey
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Registered: 7th Sep 03
Location: Wigan
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these air free subs expensive??
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Dom
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Registered: 13th Sep 03
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about the same price as any other, although get something decent...ie: not kenwoods free air subs, but you will find that most decent ones will need loads of power, like 800wRMS and of free air subs you cant really go much lower that the RMS rated wattage.
However, if you are going to make your own parcel shelf, make sure its strong, so find the thickest stuff you can get your hands on and also make sure its fixed to the car firmly !! Ie: bolt the thing to the sides, not just rest it on (like the original parcel shelf in a corsa)...since its gonna be holding up quite abit
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baza31
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Registered: 19th Apr 03
Location: yorkshire
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10mm mdf! that´ll jus snap, if ur gonna be hangin a sub on it i´´d have thought even 20mm mite break
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
User status: Offline
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yep its not the shelf that snaps its the supports!
I got an autoacoustics shelf and it held the sub easy, but the plastic side mouldings couldnt take the strain and snapped.
You would need to reinforce them somehow. For cheap, Alpine type-S subs are free air capable and require 200w RMS. Not too heavy either so a good possibility if u REALLY want to do it.
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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quote "but you will find that most decent ones will need loads of power, like 800wRMS and of free air subs you cant really go much lower that the RMS rated wattage. "
I disagree with this. Free-air subs are VERY efficient subs if done properly. They do not require vast amounts of power. They may be able to handle 800rms thermally but no way mechanically, they will FREQUENTLY reach their limits of excursion with high power causing bad damage to the copper coils...
Also what do you mean by "you cant go lower than the RMS value"?- What will happen?
If you want loud (SPL) you need LOTS of power and BIG woofers with BIG enclosures. If you want to keep the rear seats then a single 15" with a HIGH rms value hooked to a very powerfull amp of equal or slightly bigger rms value and a tuned ported enclosure is the way...
What kind of budget are you on?
[Edited on 28-12-2003 by TOMAS]
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baza31
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Registered: 19th Apr 03
Location: yorkshire
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if u power a sub higher or lower than its rated rms i.e runnin a 300w rms sub off a 150 amp or a 600watt amp it will fuck up the sub, i suppose if u run it a low volumes it will be allright but if ur amp is too power full u will just blow ur sub. u want an exact match or an amp that is slightly more powerfull.
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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That is VERY wrong. A 50wrms amp WONT kill a 200wrms sub IF its set up correctly. Its all to do with clipping which overheats the coil. So long as the amp is set up so that it doesnt clip then you are fine. As for more power the same rule applies, so long as its clean it shouldnt kill the sub. Granted the sub wont last as long but it wont kill it. Ive ran a 500wrms sub with a SOLID 850/900wrms before for 12months. The sub never got damaged. Right now im running a pair of 12's rated at 300wrms each with 550wrms each and no problems... Its to do with setting the amp up properly. LOTS of people dont know how to adjust gains correctly!
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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I agree Tomas free air subs usually use low amounts of power due to the ease with which the cone moves.
As he says setup is very important as free air subs will hit maximum excursion much more easily than a sealed sub.
Tbh u r better off with a sealed box, my alpine was in the shelf and didnt sound good at all really, now in corsa its in a sealed box and its fine.
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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C i know my stuff LOL I ought to for 4years worth and £3.5k later...
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
User status: Offline
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Yup, i like to think im not too sloppy either!
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