Rear parcel shelf-structual rigidity. 12" subs.

[AANDYY]

Hello all, I'd like to know if the rear parcel shelf of my car makes up some part of the structural rigidity of the car?

I want to make the rear speakers cut out larger for 2 12" subs I already have in an amplified enclosure in the boot, the volume level is poor/low due to the sound deadening in the boot, plus the fuel tank is in there as well so that won't help much .

Another question is, how do I remove the shelf lining, I've had look but couldn't see anything obvious.

I understand about speakers being in free air handle less power but I think because they are effectively 'in' the car the lower watts driving them will be OK and sound louder.

 

[cleverdicky]

LOUD is for knobs and immature boys with small penises.
Your driving a Mercedes for Christ's sake.

Quality over quantity my friend.

 

[Will]

A little uncalled for perhaps?

Not really my cup of tea (cutting the metal parcel shelf) but I don't think there's any need for comments like that.

Will

 

[Dieselman]

Andy. Next to the speakers is another hole with thick sound deadening foam over it.
I suspect that if you clear the board you have covering it, then cut the foam out or make a port you will hear the sub well.

To get the rear shelf cover out you have to remove the seat then the headrests.
The headrests remove by unclipping the surrounding bezel then reaching through to the clips on the folding mechanism and giving the headrest a thump from behind.

The shelf metal is structural but it's part of the whole seat frame section so cutting it wont matter apart from the reduced fire barrier.

 

[wemorgan]

It offers a small amount of torsional stiffness, but since there are holes in it anyway the size increase will make minimal difference.

The more significant contribution will be to cabin noise reduction. The parcel shelf reduces the cabin volume and reduces the booming noise you can sometimes hear in estate cars.

 

[Bobby Dazzler]

Not answering your question but, another thought given that you already have the enclosure built up. Could you port it through the ski hatch behind the headrest?

If the enclosure has been built specifically for the speakers, then they should (theoretically) perform better than parcel shelf mounting them.

 

[verytalldave]

It seems a shame to spoil that nice parcel shelf..............
Before cutting or drilling anything, why not see how a sub performs WITHOUT cutting anything first.
Remember, the frequencies involved are all below about 200Hz and those low notes will find their way into the cars passenger area just through the fabric of the cabin anyway.

 

[grober]

If you have 2 existing rear parcel shelf speakers,if you removed them would that allow the sound from your amplified enclosure into the main passenger compartment?

 

[AANDYY]

Not answering your question but, another thought given that you already have the enclosure built up. Could you port it through the ski hatch behind the headrest?

If the enclosure has been built specifically for the speakers, then they should (theoretically) perform better than parcel shelf mounting them.

Arr, if only I had a ski hatch , no ski hatch as the tank is a single tank, not saddle tanked.

It seems a shame to spoil that nice parcel shelf..............
Before cutting or drilling anything, why not see how a sub performs WITHOUT cutting anything first.
Remember, the frequencies involved are all below about 200Hz and those low notes will find their way into the cars passenger area just through the fabric of the cabin anyway.

I agree but for some reason the sub just doesn't get through enough, for me, I don't want my ears to bleed but it's not even close to when I had a 10" sub in tube (Pyle) in my Mondeo.

I even tried removing the parcel shelf speakers but that made very little difference.

The enclosure I have is this and it's 1000w max! so about 500w RMS, I'm running at the max now!

It was only £70 (reconditioned) so worth it just for the amp.

I,m hoping that when I'm finished the top side of the shelf will look OEM, I hoping I can remove the insulation from the covering where the speakers will be and leave top bit intact, hope that makes sense.

 

[vijilants]

I had the same FLI box in the back of mine and as you said, it did not make any difference.

I got rid of it to a friend of mine who has an estate and there it does make a difference.

The Merc boot is just too heavily insulated.

Why not put some 6x9 's onto the back shelf ?

This would mean that hopefully you wouldn't have to chop away any of the metalwork and they can be mounted from below so that they won't be seen.

 

[AANDYY]

I just don't think 6x9's will give me the type of sub bass I require.
I don't mind doing the work, quite enjoy it. After all I have drilled a hole in my roof for my DAB antenna.

 

[brens-e200]

hi Andy,

have you thought about an under the seat set up such as the SRV313 active sub from clarion ? which fits under the seat. I have been asked the same question by my son as he also wants to install subs in his e200 and this may be a solution for him so i'am looking at other alternatives as well.

Option 1:

Afaik there are door speakers in all the doors with tweeters up-front. The smaller shelf speakers could be removed and install a pair of good 6x9's in their place to be fed from an independent amp . this way you can look for 6x9's that have the best bass response figures.

You would have to remove the additional baffle material in the shelf's speaker housing

Option 2:

create a shelf (mdf) using the spare wheel mat as a template and install the woofer so that it fills the void in the spare wheel. You could then use metal pieces/hinges to fit into the guide slots at the rear of the mat to provide an anchor point .

then using 1inch stand-off's build a lid to fit over and protect the woofer and as an additional protection use fine mesh to prevent debris getting in around the sides.

phew must learn how to do cad drawing as it takes longer to write it !!!!

hope this helps

brendan

 

[Bobby Dazzler]

That looks like it was designed and built as a unit - enclosure and speakers. Unless the designer was on a YTS programme then the speaker and enclosure should be matched to maximise efficiency.

They'll work if placed in the parcel shelf but wouldn't be as effective as in the purpose-built enclosure, or as another sub designed for parcel shelf mounting.

One of the first computer programmes I wrote was to calculate enclosure volumes and dimensions for loud speakers, but it was in Fortran77 and if I still have it will be on floppy disk, so not really much use in the 21st century!! Sadly I knew nothing about accoustics, just how to apply the theory to create the program...

 

[Rob77]

My car's a different model and so it could well be a bad example to cite but someone (prior to my ownership) has removed the metal parcel shelf and replaced it with thin (ish) ply to allow bigger speakers to be fitted.

Must've been a bit of a job though because it all looks exactly as it should.

Unless told it was there I doubt anyone would notice any lack of rigidity or aesthetics or increase in unwanted sound.

 

[Paul XE]

LOUD is for knobs and immature boys with small penises.
Your driving a Mercedes for Christ's sake.

Quality over quantity my friend.

Sorry to drag this back up, but I find this very offensive. I think you
should keep your opinion to yourself and remember that we all have different interests. If someone enjoys loud music it does not make them immature and because we drive a mercedes, we do not automatically have to listen to Radio 4 through the standard stereo. (not that I've got a problem with Radio 4 btw!!)

Rant over.

As for the subs, I would remove the standard speakers in the rear shelf and that will allow the bass to come into the cabin. The subs will work loads better in the correct size box than on the rear shelf firing into the boot.