You DON'T. You buy the right size unless you are into serious metalwork.

I think I'm going to have to whip off a door panel and take a peek at the speaker before doing absolutely anything at all! OK? so how do you rip off a door panel? crowbar?

Blowtorch should do it in your case

In the Octavia's case there's no need to remove trim panels - the grille over the speaker pops off and the speaker itself is removed from the front by undoing 4 screws. YMMV

No sign of any popping off panel on mine - looks one complete unit. :(

I'll have a look with a screwdriver / chisel / axe / gas cutting torch tonight.

My Mummy always taught me "you look with your eyes, not your fingers" (or a screwdriver)

Well - eye's first but I'll probably blame the fact I wasn't wearing my glasses on any damage I may inflict. I've always been kind of curious what exactly is behind the plastic facade, so if anything I'll do it just to cure the curiosity. Good job I'm not a cat.

I've always found wattage ratings on speakers a little strange, as I've always been under the impression the amount of power they produce is more to do with the amp you drive them with! I'd just ignore this, and look at what the cones are made of. And price is always a good indicator.

Rob.

OK - studies the booklet and I "think" this is what I need to do.

1) no power cables included, so I need to buy 5 metres of chunky power cable, and about 2 metres of slightly thinner power cable (chunky stuff is about 10/12mm thick - thinner is about 7mm)

2) The previous owner of the AMP had setup the fuses & ring terminal for the battery which is ideal. Also included a 2 into 1 for the chunky cable to provide power to the Amp and Sub from one lead.

3) Need to check AMP at home tonight with regard to RCA cabling - there was something, which may be it. Also need to investigate if there is a 12V wire with an on/off switch to remotely turn on the amp from my drivers seat.

4) everything else looks fine, and I must commend Rockford Fosgate on their precise (if a little Americanised) instruction booklet - Quote - "you'll need a 3/32" & a 9/64" allen wrench" - so that'll be a set of allen keys then...

Tonight I'm going to start fitting this damn thing. Q - power cables you had - I really would like to get your, but this means waiting until the 19/20 Sept, and I really want it up & running earlier. If, and if, you really want to get rid of it, I may rip out all the panels, plumb in the RCA cables, and simply then you can supply the power (if you have the right cables) and there could be a group fit & test at the weekend?

Originally posted by devonutopia in this post

3) Need to check AMP at home tonight with regard to RCA cabling - there was something, which may be it. Also need to investigate if there is a 12V wire with an on/off switch to remotely turn on the amp from my drivers seat.

There should be a "remote" output from your headunit, which sends a 5v signal (?) down to the amp (if it has a remote input - it should) which then turns it on. No need for on/off switches...

What if I don't want the amp/sub for listening at some stage? I thought a 12v remote on/off would be good, if the AMP has the facility to have one? (which it does) -another switch for me to fiddle with.

Jason, the cables are absolute obsolete in my case so you can have them for a small token. Getting them to you is as you say the hard part. I'm still in doubt if I can make it to the national, so that doesn't help your case.

Jason - why wouldn't you want the sub/amp powered? It will only be on when the headunit is, plus if you don't want lots of thump, turn down the volume on the HU or adjust its bass settings...

Having it triggered off the HU will definitely be better than having a manual switch, as it means it will be controlled by ignition...haven't you pestered the AA enough without having to get them round to recharge your battery?

The RCA cables should be a long set of "phono" leads, bit like what comes with home hi-fi stuff.

Rob.

Yeah - but you know me and fiddling with switches. Adjusting the bass on the amp itself is a bit of a pain because it has two allen keys to undo the side pod to access the twiddly bits. Unless, of course, I try and mount the amp in the passenger compartment somewhere?

You shouldn't really need to fiddle with the gain once it's set! Yeah, you could mount the amp in the passenger compartment somewhere, would save a lot of cabling...

Rob.

Jason, I think Steve meant you could turn down the bass on your HU. Would reduce the output to your sub accordingly.

Originally posted by robmawer in this post

You shouldn't really need to fiddle with the gain once it's set! Yeah, you could mount the amp in the passenger compartment somewhere, would save a lot of cabling...

Rob.

Under the passenger seat?

Would it? I guess that's where the RCA comes in... I thought about securing the amp on the passenger side of the central column bit, but I thought it would be a bit of an attractive smash & grab item/ :(

I'll stick it in the boot as I first planned - It's got enough cable I reckon, plus I'd need less smaller cable to go from the splitter between the amp & the sub... I'm starting to talk like I know something about wiring now - that's worrying?

Hopefully, you'll only need to adjust it once and then leave it.

Turned mine to 'max' and have never so much at looked at it since

Well, if you mounted it in the passenger footwell, the trigger wire, RCAs and power cable would all be shorter - in fact, for an amp that size, if the power cables behind the HU are as substantial on the Octy, you could possibly get away with powering it off this loom.

Then all you'd need to do is run speaker cable to your sub.

Rob.

The power cable came with a ring-term for the positive terminal on the actual battery - I'm going to use that as it comes recommended over any other method (in the instructions) - plus the previous owner has left the ring-term & the 40A fuseholder setup complete, so I may as well use the same method? The same goes for the 2 into 1 splitter. The bloke previous must have used that too to power the amp & sub from the same power cable, just splitting it in the boot...? I assume this is the case anyway as the splitter was not part of the amp's original package...

I'm popping down to one of my work's 'leccy suppliers for some cable in a minute.

Just make sure they don't give you twin & earth, Jason!!

Well, depends what car it was in previously - not a lot have very substantial power cabling. Having a dedicated power cable will probably give best results, but is more work.

One thing I am curious about - why do you need power to the sub?

Rob.

Would there be a filter/crossover in there that would need power?