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9N boot build done

Posted: Thu Jan 03, 2008 2:53 pm
by david burton
I bought a Boston G5 and Passive rad a month ago from a guy on Talkaudio so decided to do a proper install in the 9N.

It came with its own box and both sub and rad are 10" in diameter, the box only needs to be 0.5cuft in volume but the existing box was about 0.7cuft. The idea of the passive rad is to increase the response by 3dB because it acts as a port, but you can still keep a small sealed enclosure.

Initial impressions with the old box were excellent. It's almost unbelievable how loud the bass is for the size of enclosure. I'm running the sub through a Genesis sub amp. The size of the magnet on the sub is enormous and it runs fine at 2ohm load. The SQ is tight and accurate, but it can really hit low too - it's louder than my 2x12" I had previously.

The old box:

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So the idea was to get a proper 0.5cuft box with the sub pointing either up or towards the boot.

The Boston manual shows a opposite sides box for the sub - rad mounting, a side by side would just end up too big (volume wise) because it only needs 0.5cuft and with the depth of the sub I'd be stuck or making a very very awkward box - just the sub side would be about 0.35cuft.

I decided to go with what Boston recommend and the sound is a lot better and tighter - better SQ but perhaps not as boomy low down. Which I like. The new box is 22mm MDF with a screw every 2", and PVCed and sealed inside. It's got proper speaker wire connections at the back for easy removal.

The sub sits on top of a 40mm x 20mm frame of wood that is braced across the whole boot above and below the spare wheel (looking from the top). Each end of this wood is braced front to back too. The amp sits on the LHS below the sub with about 30mm of air space. I can remove the sub part with just 4 screws.

The rest of the boot has a separate false floor above the bracing. This means I can remove the false floor and still get my spare wheel out.

With some VW carpet for christmas I set about making the install with my Dad:

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This is the view of the rad from the back seats. The edging on the carpet isn't finished in this picture!

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I'm very pleased. Plenty of space for the luggage and a fully functional spare wheel!

Posted: Thu Jan 03, 2008 10:27 pm
by ModifiedMadness
Looking good Dave, I'll get a listen next time I see you 8)

Posted: Sun Jan 06, 2008 8:48 am
by Josh_PoloGTi
I love Boston stuff, it sounds great!

Good work with the install too.

Posted: Sun Jan 06, 2008 12:56 pm
by david burton
Josh_PoloGTi wrote:I love Boston stuff, it sounds great!

Good work with the install too.
Do you know much about the Boston RC620 components? I was thinking of getting some 2nd hand but they might be quite old....

Posted: Sun Jan 06, 2008 1:15 pm
by Josh_PoloGTi
No, sorry.

The only Boston components I've heard are the top end ones (I believe they were about £650 at the time).

I've got a Boston amp which has run the front components on my last two cars and I've been very pleased with it.

Posted: Sun Jan 06, 2008 1:20 pm
by david burton
Cheers

what front comps have you got in yours at the moment?

the little G5 sub is superb for the money, even running off the Gamma outputs.

Posted: Sun Jan 06, 2008 5:07 pm
by Tim_GTi
install looks reallly smart 8)

so your amps hidden underneath the box?

Posted: Sun Jan 06, 2008 6:47 pm
by david burton
thanks

yes, the amp is underneath the box with an air gap and the false floor is about 2 inches off the normal floor so there should be plenty of air to circulate. I added a black grill in front of the sub just in case.

Posted: Mon Jan 07, 2008 5:45 pm
by Hardcore
you sdure that box is bigg enough for them subbs lol. with the air mass. boston aucoustics are very good. normally need one of them boxes for one subb. not two in one:O

Posted: Mon Jan 07, 2008 6:22 pm
by david burton
it's not 2 subs, it's one.

Posted: Mon Jan 07, 2008 10:42 pm
by Hardcore
o ryt . i was looking at the old box lool :lol:

Posted: Mon Jan 07, 2008 10:51 pm
by Josh_PoloGTi
Hardcore...

Both pictures show one sub... The other thing in the box is a passive radiator... Like a speaker, but with no magnet or voicecoil etc.

David...

I'm running standard Audi front components at the moment with a JL sub run from a Kicker amp... All driven from an Audi Concert head unit.

Cheap system for the runabout :)

Posted: Tue Jan 08, 2008 11:18 pm
by david burton
Josh_PoloGTi wrote: I'm running standard Audi front components at the moment with a JL sub run from a Kicker amp... All driven from an Audi Concert head unit.
Josh, do you know if it's feasible to leave the VW wires in place and amp these wires directly? I'm trying to decide what to do with my 2nd amp and I was wondering if I 100% need to change the wire to the mids in the door.

Posted: Thu Jan 10, 2008 7:45 pm
by Josh_PoloGTi
What I've done in the past is to run the speaker wires from the amp in the boot to behind the stereo, then cut into the adapter harness between the head-unit and the OE ISO block so that the feed from the head-unit is cut and the last few feet of wire to the speakers are OE.

Worked fine for me... Although I was only running 25W RMS from the Boston amp through it.

Posted: Thu Jan 10, 2008 8:20 pm
by david burton
I'm thinking of doing the same but putting the amp under the passenger side dash (it's a small Genesis).

I can then intercept both the power and the remote wires as I wired them through that side.

This saves me having to sort out space in the boot which I'm not sure I have! It also means the RCA is easier to use as fitting 2 RCAs down the driver's side moght prove a bit trickier.

I'll have a further investigation soon enough

cheers