JockyTT

Well, I have finished. A lot of pondering and measuring finally pays off. Thanks to Chiark for the recommendation and the idea that I finally used to fit the blasted things.

I bought materials to do both an install from below the parcel shelf or above, by making a new MDF shelf. This was to fit in a bug eye saloon.

I removed the rear seats and removed the rear parcel shelf (which is a heck of an effort). I made a template and fashioned a replacement shelf, though in the end I was not happy with either the fitting of the shelf or the fact that I would still have to space the 6x9's a little above the shelf because the magnets are deep.

So, I made from 12mm MDF, a regular oversized rectangular spacer and placed this where I eventually wanted the subs to be - under the rear shelf. I drilled 6mm holes (4 for each) in the shelf from below and held the spacer in place using bolts. Then I cut andfabricated parts of mdf to fit inbetween my spacer and the shelf underside as it is not level, finally glueing these additional bits to my spacer and allowing the spacer to sit level under the parcel shelf with a flat surface to mount the driver to.

The first two pics show the spacer in place and me fitting additional MDF to fit the contours of the shelf. The last two are the 6x9's in place.

Well worth it - The sound is brilliant. I have taken up no boot space hardly, and the subs are not visible from above. I just now have to stop the cardboard parcel shelf rattling....

Steve

chiark

Very, very neat

Enough bass from them?

The more I look at this, the more I think it's the best compromise for almost everyone: speakers in the rear doors if you need 'em, subs on the shelf giving some bottom octave output, and a decent set of front speakers.

Chuck a 4 channel amp on there, and you've got a very respectable sound system...

So, theorising for a moment (sorry!)
Head unit: 250 quid
Amp: 150 quid
Fronts: 150 quid
Subs: 150 quid

700 quid for a very, very nice sounding setup... Not too shabby, but you can save by buying second hand components too.

[Edited by chiark - 1/21/2004 5:09:14 PM]

JockyTT

Nick, you been looking at my bills?

That's exactly what I have done. The fronts are running off the HU at the moment, as are a pair of 4" rear doors.

The subs are 100w RMS so match fine with my Pioneer 4 channel amp if I bridge it.

The bass is great. Just have to finely tune the gain on the amp.

Question though, if the HU has a subwoofer out and I set the LPF on the headunit do I need also to set it on the amp or is that effectively filtering twice?

jag_h

if you low pass on your HU, then you dont need to filter on the amp and vice versa.

if for exapmle your HU is LPF @ 125Hz, then you amp will usually LPF @ 80 Hz. all this means is that you HU is only sending frquencies below 125 to the amp then the amp is only sending <80 to the speakers.

you may as well just use on filter...

chiark

I personally use as much filtration as is available. My sub channel is low-passed on the head unit, and on the amp... It won't hurt, and will ensure that you get less midbass where the sub should be.

Try both ways. For the sake of half an hour's fiddling it might make the world of difference - as may reversing the phase of both the subs?

WRX_Rich

iTrader: (5)

good man, I ve got my self a 4 channel amp, 6 x 9s and a 4 channel amp to go with my 2 kappa fronts and vibe sub

just need to fit it all now,Think i'm gonna copy your install

cheers for showing us all

Nathan L

The only thing that has put me off doing this is how much metal there appears to be in the path of the sound. On the second picture down the spacer really cuts in along way under the chassis.

Is the carboard shelf rattling or is the sound hitting the metal shelf causing vibration?

Not criticising just interested?

Nathan..

chiark

The metal will make knackers all difference. Some subs sound better with a bit of front loading - my Infinities definitely used to.

It strikes me as a stonkingly practical solution to how to get some bass response in your car.

Nathan L

Nick

Like I said I'm not criticising.

Just didn't know.

Nathan..

JockyTT

Nathan, you're right I thought this too, though I also decided that I didn't need to direct the sound so much with them being subs so I took the risk. There's no way that you can make use of all of that stupid shaped hole as you've probably guessed.

With regular 6x9's you may also need to consider venting to the cabin somehow. One trick (Ali-B was it?) was to part drill holes in the rear shelf to form a grill type affair.

The rattling is coming from the seatbelt mount and the plastic cover around it. The shelf really isn't that bad now.

Steve

Nathan L

Steve

Thanks for the reply.

I have some regular Infinity 6x9's and an amplifier just sitting in my garage. This seemed the easisest way of fitting them but I was worried about how the sound would travel up and through the shelf.

I suspect that as long as I make sure the mid + treble sits through the hole in the metal shelf they will sound okay.

Cheers

Nathan..

chiark

Ultimately the mid and bass will be dispersed by the rear glass anyhow, so reflecting off a bit of metal first really shouldn't make that much difference.

I realise you're not criticising

Cheers,
Nick.

JockyTT

Nathan,

Yes I'm sure that's possible. The centre of the 6x9 will match with the hole in the shelf. If it's more bass you're after you'll probably be ok. If you want the high frequencies, you may want to think about what to do with the cardboard shelf. It's got some insulation on he back of it as well...

cheers

Steve

hades

I know I have drilled lots of small holes in my OEM rear shelf in a grill type affair (although I'm only running 6.5" components in it). Drilling the holes definitely helped air movement through into the cabin, and reinforced the bass nicely. Seal around the apperture with a small bead of bluetack to stop the sheld vibrating, and you're well away.

I spent more like £800 all in - £400 MP3 H/U and in-dash changer, £150 front door speakers (although I already had these), £180 rear speakers and 4 channel amp together, £50 rear door speakers. Works very nicely for me.

Jza

Fantastic stuff Jocky,

Can you just clarify....

1) You just put the original rear shelf back on top - no need to cut holes etc?

2) How did you get the rear shelf out - i've had a look and cant figure how you do it!!

3) HOW DOES IT SOUND??? I've wanted to do this for ages !!!

Jza

Edited to add

Whats the model no of these subs? I need to get looking for a good deal

JockyTT

ok, well

1. The speakers are mounted from underneath so the original shelf fits straight back on, no problem. It vibrates a bit so I've used upholstery foam to pack out the gaps between the shelf and the bodywork.

2. The proper way is a bit complicated. remove rear seat base and back and remove trim on either side starting from the plastic by the door sill and work upwards, - there are three separate pieces of trim. Remove plugs holding down the front of the shelf and then pull the shelf up.It's held on with more plugs.

3. The sound is great - not as much bass as you would get with an enclosed sub but brilliant nevertheless.

4. The part number is GENP619014

Jza

Thanks m8 - looks like i'll be having a fun bank holiday then!!

Cheers

Jza