Sub in boot tray?

[andydckent]

I've been searching for a bit and I know I have seen it somewhere before, does anyone know where the thread is on installing a sub into the boot tray without removing spare tyre etc? Or was that on OZVR4?

Cheers!

Andy

[Turbo_Steve]

This?

http://www.clubvr4.com/forum/showpos...86&postcount=9

[andydckent]

That's the one! Thanks Steve!

I think its time to compliment the nice focal speakers I installed last year with a wee bit of bass. I've got an old kenwood 800w amp lying around somewhere and since its staying light outside a bit longer now maybe its time to start tinkering again.

Was it difficult to do, what do I need and whats the procedure?

Also does anyone know if its possible to test the safety of an old amp? It has been lying around for years and it wasn't new when I got it.

[VR4WGN]

or you could hve the Factory twin 10" sub setup that Mitzi designed for the legnums.. i have a box here and i loaded pics up ages ago ,just browse d-package or similar,

[elnevio]

I knew Hairdryer_Steve would have been on the case on this one!

[Turbo_Steve]

I'm not aware of a reliable way of testing an amplifier without a bunch of specialist equipment (load shunts, oscilliscope etc).

With regards to fitting a sub in the tray, get one with a nice rigid suspension and then measure it. If possible, get your hands on a replacement load tray in case things go horribly wrong.

Then start choosing locations where the sub will fit, and drill a hole where the middle of the sub would be. Poke a long stick through, and confirm that there is enough depth when the tray is down. It's basic, but it flippin works.

On mine, the sub would have sat 10mm too low, and fouled the spare wheel. I knew that the total cone excursion at the front (Fmax) was 12mm. So I had to leave 15mm for the cone to move. So I chose a piece of contiboard the right thickness and made it fit. Loads of glue and and screws later, I have a reinforced tray with a thickness 12mm higher. So the sub now fits.

If you're a bit more ambitious, and don't want to store lots of stuff in the tray, you can take a more radical approach. Take your jigsaw to the tray and remove everything except the outside edge, and the brace across the middle.

Then meausre up a piece of MDF to fit the bottom of the tray, and cut your subwoofer hole so that it sits in the middle of the spare wheel - this gives you massively more mounting depth (upto 50mm on a 10" sub!). Carefully trim down the plastic frame so that the total depth with the thickness of the MDF is the same as the factory tray.

Now you need to make a brace across the subwoofer that will support the boot floor, but bridge the sub without fouling the cone. I was planning to use a length of steel box-section for this, running across the whole board, but mounted on wooden blocks to the correct height. However, I was lucy and found my sub fitted

This second method should sound better, and has the advantage of more flexibility when it comes to amp layout, cabling, etc. You can mount a couple of LEDs on the bottom of the steel bar to illuminate your sub if you like that kind of thing.

[elnevio]

I was lucy

I have always been suspicious...


Otherwise, good info!

[Turbo_Steve]

Gaaaaargh!!!!

[Mark 4]

Lol Lol Lol.

[andydckent]

Thanks for this Steve!

The factory twin sub thing looks cool VR4WGN but I doubt there are any over here.

Just need to find a suitable sub speaker and decent wiring kit now. Tempted by one of the focal 10" ones that retail for about £80 just to keep it all Focal, but not sure if its really worth it.

[Turbo_Steve]

Focal! Moist!

You could do a lot worse than a JL sub, if your budget will stretch. Alternatively, pick up some cheapo bass box off e-bay, rip the cone out and chuck it in and see if it survives.

[andydckent]

Next question before I end up doing a rush job. Where is a good place to ground the negative connection to the amp?

Also which wiring kit to buy? Its a mystery to me... I know I need power (fused and pre crimped), earth, speaker cable, remote cable, audio cable.

http://caraudiosecurity.com/shop/pro...ring-kits.html

[Turbo_Steve]

Well, to get mine working I just bared the end of the earth and clamped it with the spare wheel bolt.

To do it properly, you need to find a decent part of the chassis, drill a hole, scrape off some of the paint and bolt a lug to with the earth crimped in.

Wire-wise, do it once and do it right: get some 4awg and run it from the battery into the wheelarch, over the wheelarch and in through the rubber grommet next to the door into the cabin, then along the floor under the carpet to the boot.

You must must MUST put a fuse in. It SHOULD be as close to the battery as possible, though all the fuseholders I've had seem to go brittle and shatter this close to a turbocharged engine, so I sheathed the wire in a second layer of plastic, and put the fuse in the cabin. I wouldn't reccomend this to anyone else, though.

[andydckent]

Thinking about this again has got me wondering about whether I should buy an amp for my focal door speakers. I have the 165A coaxial and components but the stereo out is only 50w where as the speakers are Max. power handling: 120W Nom. power handling: 60W. If I was to do this what would be a reasonable amp and just how difficult is the wiring and is it worth the time and effort?

I will run the focal 25a1 sub (Power Handling: 200 watts RMS/400 peak) off the kenwood 7201 800w amp in bridged mode. Does that sound sensible?

[Turbo_Steve]

Andy - Buy Gowf's HiFonics amp - it should run the sub and speakers adequately in one package. Wiring is a bit of a pain, TBH, as to get the full benefit you really need to run fresh speaker wire into the front doors. Plenty of people just run speaker wires to behind the headunit, and then send the signal down the factory wiring, however.


Your headunit is quoting 50wrms power output?
Hmm....What size fuse does it have in the back? 20A?

The thing is, they all quote these amazing figures, but outside of a lab, you are NEVER going to see that headunit produce 50watts RMS.

Most headunits rated at 4 x 40wrms typically deliver 4x20wrms (yes! really!) with transient peaks as high as 35.
What you'll find is that as you turn the volume up, the system starts to sound "harsh", prior to full on distortion. It's tiring to listen to.

If you run your front speakers off a proper standalone amplifer (with a proper power supply) then you'll get much better sound, for much more of the volume range. Ideally, if you have a sub, you'll be able to run a high-pass filter at around 60-80Hz, too, which stops the speakers flapping around trying to produce frequencies that are too low for them, which in turn improves the effective power handling of the amplifier (it's not trying to generate huge bass waveforms for speakers that can't handle them, leaving more Powersupply headroom) and the speakers will suffer from less distortion as they are trying to reproduce a narrower frequency band.

It's a multiple-win situation.

The catch is that the focals are good. Really good. Which means your amplifier and headunit need to do them justice. Which means you need something as good as, or better than, a Hifonics or Pioneer.

In an idea world you'd look at MTX or (best yet) Pheonix Gold (moist) or even Genesis. After that is starts getting REALLY expensive.

I'd seriously have a look at Gowfs, and see what you can get for the Kenwood on e-bay? I know it looks like it'll only do 200watts for the sub, but it's fairly underrated kit - chances are it'll give you enough of what you want.

And if you want more from it, you change the focal sub for a dual voice coil one, and run it at 2Ohms instead.

[andydckent]

Thanks for all your advice Steve!

I am coming round to your way of thinking.

Can you advise me would this be the appropriate wiring kit?

http://caraudiosecurity.com/shop/pro..._id/12683.html

Also I would guess that I'll probably need an additional 20ft of speaker cable, what would you recommend?

http://caraudiosecurity.com/shop/pro...ker-cable.html

It seems to me that by the logic of running the sub with more power than its rated would mean that 200w would be a bit low, but I suppose I could run both amps? I doubt I'll get much for the kenwood one.

[Turbo_Steve]

The power kit's about right.

I'd suggest the speaker cable is somewhat overpriced.

Have a look at www.maplin.co.uk, stock codes XS47B and XR60Q

I would suggest that XS47B is probably more than adequate for the job in hand, and just as good as any of the stuff you've listed. Bear in mind that if you go too heavy duty, it starts to become difficult to get the speaker cable to where you want it!

[andydckent]

Well that is everything on order, Focal 10" Sub, 4 awg wiring kit, 10m of extra speaker cable and Gowf's Hifonics 1000w amp which he is bringing with him when he comes to Edinburgh!

I suppose I should now think about getting some MDF to fit in the boot tray and cutting it to size.

[Turbo_Steve]

I'd start measuring things first! It'll tell you how much cutting / shutting you're really going to need to do.

[andydckent]

Just been reading the spec on the Focal 25A1 sub. It suggests using a vented enclosure. Bearing in mind the enclosure is the spare wheel area would it be worth creating a vent near the speaker, and if so where?