I learn something every day- thanks Dukk!

 

That's pretty common in Toyotas and some other Asian cars.

Just be sure the crossovers are where they can't get wet. If I must mount them in doors I try to do it on the outside of the plastic water barrier.

 

Wow I really screwed that right up. What was I thinking! Spent the morning taking the crossovers out the door cavity and locating under the dash (thanks Dukk) the tweeters are now above A pillar.
Everything installed and car interior back together, the tweeters and mid sound great, the sub is underwhelming although I wasn't expecting miracles from an 8" under the seat job. I haven't had time to tune in the sub properly ,so may still be able to get some decent low end out of it yet.
It ended up being a lot more work than I expected but I did have to do some things over (duh). It was a good challenge for me, I learned a lot for next time and I'm pretty happy with the results so far.
Many thanks to those who offered me advice and helped me through the install

 

I set the gains on the amps and the little Sony 50w rms has so much headroom, it cranks out heaps of power with the gain hardly turned up at all
Whereas the fusion sub with built in 100w rms amp has to have the gain almost all the way up to be audible
I have to run the treble on the head way down and the sub at maximum also to have any kind of balance to the sound

I tested the rca leads to the sub by pulling out one at a time and they seem ok because volume drops slightly when either one is disconnected
Is it something to do with the main amp being on high level inputs and the sub being on preamp channel?
Is it normal for these slimline subs to just be totally gutless?
The fusion sub is second hand maybe it's just stuffed and I should just buy something else?

 

yes....

 

Honest truth is the sub you have is likely insufficient for pretty much anyone. Craigslist it and look for something better.

 

Ok the slimline 8" is gonna go
A guy local to me is selling a Phoenix tantrum 600.4 with a Boston acoustics 10.5lf plus housing. He wants nz$200 each , it's older gear I know but they seem to be in good shape.
This setup looks like it will do the job, or am I better advised to get something new (and lower spec) for the same money

 

Sounds like a good sub but you could do a lot better on the amp. The amp is a 4-channel. You'd be better off finding a mono amp for that subwoofer. find out if it is dual 2 ohm or dual 4 ohm. This would be the deciding factor on the amplifier.

 

I dont know if its dual 2 or 4 ohm , here is the blurb from the ad

Tantrum Series 4-Channel Class AB Car Amplifier
RMS Power Rating:
4 ohms: 75 watts x 4 chan.
2 ohms: 150 watts x 4 chan.
Bridged, 4 ohms: 300 watts x 2 chan.
Thermally efficient heatsink
Timed Acoustically Integrated Muting (TAIM)
Differential RCA or speaker level inputs
Tri-linear capability allows simultaneous stereo and bridged operation
18dB / Octave High-Pass, Band-Pass, and Low-Pass Crossovers
40Hz to 800Hz Continuously variable crossover frequency
Auxiliary outputs route inverse crossover signals
Variable Twin-"T" bass EQ circuit provides Up to 18 dB of boost at 45 Hz
Optional RMD remote monitoring display port
Optional LPL low pass level controller
2 Ohms bridged stable
Amplifier type: multi-channel
Speaker level inputs: yes
Preamp outputs: yes
Built-In Crossovers: HP/LP
Bass Boost: 0-18 dB
Frequency Response: 20-20,000 Hz

I could bridge two channels for the sub and use the other two for my fronts ? (Thought it would be an upgrade from the baby sony amp they are on at the moment).
Got the feeling I might be wrong again.
I'll check out some mono amps

 

Chilling parked up the new setup sounds great by the way. Its just driving when the bottom end falls out.. but I am driving a 97 Corolla which makes a bit of driving noise , a 10" sub in the back might fill out the sound a bit.