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Discussion Starter #1
Well, near me actually. In my garage, in fact. Finally decided to do something serious about the sound system in my Exige. Basically the components are:

1) Alpine 9820 Head Unit (Standard with my Exige)
2) Focal 100CV1's in front, Focal 130CV1's in back (been in for a while now)
3) Alpine PDX 4.150 Power Amp (4 x 150W/channel)
4) JL Audio Stealthbox

A few details: the front and back speakers have been rewired and are now in parallel driven by channels 1 & 2 of the PDX 4.150 (150W for each front/back pair), the Stealthbox is being driven by channels 3 & 4 bridged to 300W.

The install's not quite complete but since the head unit's back in, the four Focals are rewired, reinstalled and hooked up to the amp, and the Stealthbox is sitting on the sill wired to the amp as well, I fired it up. I think I'm going to be happy. :coolnana: I still have to some wire routing to do (hard part done: wires are out of the dash and on their way to the center tunnel.

I figured out a way to run power to the amp by going through (without damaging) the grommets in the boot and firewall. Wire looms for all cabling... no bare wires. It's been a long day though, so tomorrow I'll finish, post pics, and go for a drive :shift:
 

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I listened to the PDX amp last year and really liked it with a variety of 4 ohm speakers. It's rated for 150 RMS with both 2 & 4 Ohms, how do you like it with the 2 ohm load you are using with the parallel Focal's?
 

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These photos are from the first phase of the install...

Pic 1) The power lead for the amp was snaked through the wire loom for the main battery cable. After it makes it into the engine compartment it gets its own loom and heads for the firewall grommet behind the driver's seat.

Pic 2) Access to the firewall grommet from the engine compartment is easiest through the driver's side air scoop. As mentioned in this thread: http://www.elisetalk.com/forums/showthread.php?t=13336&highlight=wire+routing the wires going into the firewall grommet are wrapped in tape, making a pull through them difficult. The tape can be removed without too much difficulty, which is what I've done, make the pull much easier, and then retaped after the power wire was pulled through. This picture is taken through the side scoop opening.

Pic 3) The driver's compartment side of the firewall grommet, with the power wire coming through. Since I have a harness bar, taking off the firewall panel seemed like a major inconvenience... but luckily I didn't have to.

Pic 4) Wiring diagram on top of the head unit. The sleeve of the head unit was covered in dust from a spirited group drive on Engineer's Road during the "Stig Party" :evil:. Anyway the point is pin 10, the remote power pin that the amp needs to turn on and off with the head unit. Once all the RCA jacks were installed on the back of the head unit, I threaded a tinned 18 gauge wire into the empty (as in no pin) #10 slot in the connector, and taped it to the existing harness to ensure that it stays in place.

Pic 5) The dash after all the wire pulls, but before installing the looms. Note new speaker wires to the fronts, and the brown wire which will carry the remote power signal from the HU to the amp.

More to come...
 

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Discussion Starter #4
I listened to the PDX amp last year and really liked it with a variety of 4 ohm speakers. It's rated for 150 RMS with both 2 & 4 Ohms, how do you like it with the 2 ohm load you are using with the parallel Focal's?
That was certainly a factor in deciding how to configure the system... I really wanted a solid amp powering all the speakers... so far I've tested the system with the fronts and backs in place, but with the sub not yet in its final position. It sounds very clear and crisp (and of course loud)... I've got to play with the levels and crossover frequencies on the amp once everything is in place, but even as it is, it sounds great.
 

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I didn't think the PDX4.150 liked a 2/4 mixed system, I was told it was already a hot running amp and that would drive it into shutdown in 5 minutes (local Alpine dealer). They recommended the 4.150 with a 1.600, same form factor and stackable. YMMV.
 

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I didn't think the PDX4.150 liked a 2/4 mixed system, I was told it was already a hot running amp and that would drive it into shutdown in 5 minutes (local Alpine dealer). They recommended the 4.150 with a 1.600, same form factor and stackable. YMMV.
As far as I can tell, channels 1 & 2 and channels 3 & 4 are independent of each other and have separate fuses as well (although there are modes that combine inputs), so I wouldn't think that it would make a difference if the load on channels 1 & 2 were different than that on 3 & 4. As far as running hot, I tested it for half an hour last night with the amp in my lap... it didn't seem very warm, nor did it shut down. It's going to be installed on the right side of the package tray behind the passenger's seat, so heat dissipation should be fine.

If I had the room, I'd consider going with separate channels for front, back, and sub, but... it is a Lotus; I feel lucky there's a place for the amp at all.
 

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Yeah, I lilsten at moderate volumes, I'm not pushing sine waves out for SPL competition. For some reason, SQ audio nuts are far outnumbered by bassheads, and reviews of these things are subjective, like "it shut down only after 5 minutes" [of driving 2 15" Image Dynamics woofers @ a 2 ohm load @ 145db] ;) Good luck, please post amp install pics, this is still the amp I am considering. I am aware that Alpine late 08 will be putting out a 5 channel PDX, with the same form factor.
 

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Yeah, I lilsten at moderate volumes, I'm not pushing sine waves out for SPL competition. For some reason, SQ audio nuts are far outnumbered by bassheads, and reviews of these things are subjective, like "it shut down only after 5 minutes" [of driving 2 15" Image Dynamics woofers @ a 2 ohm load @ 145db] ;) Good luck, please post amp install pics, this is still the amp I am considering. I am aware that Alpine late 08 will be putting out a 5 channel PDX, with the same form factor.
Thanks, I'm headed out to the garage to complete the install now. A 5 channel PDX, mmm? Possible future upgrade :drool:
 

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Almost done routing wires...

Pic 1) Wire looms in passenger cubby... larger loom has 4 channels of audio, remote power signal, and left front speaker cable, smaller is right front speaker cable.

Pic 2) Wire loom with "everything" going from cubby to center tunnel... speaker wires for sub visible coming out of tunnel.

Pic 3) Wire loom passing shifter on left side (stock wiring goes by on right side).

Continued...
 

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Wiring complete, last test before buttoning everything up... sounds spectacular (if I say so myself)!

Pic 1) Wiring bundle crossing under the shifter. I had to dremel out a bit of the plastic console to provide access... won't be visible anyway. Also note the ground wire attached to seat rail bolt.

Pic 2) Stealthbox in position, not anchored yet.

Pic 3 & 4) Two views of the amp. Still have to tidy up the wires. Note small dremel'd access in "cupholder" to firewall harness.
 

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where are the video monitors and PS3 controllers going?


;)
 

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Complete and road tested... I'm a very happy camper. Do you want to hear music with the windows down at 60 mph? No problem. You'll have to use the tach to determine shift points though... Frankly I haven't turned it up loud enough to make the amp or speakers distort... it's just too loud. No problem with amp overheating or shutdown. I stopped by the custom car audio installer where I bought the amp and sub, as per the owner's request, and he gave me a huge thumbs up (he does some seriously trick installs himself, so I felt pretty good about this).

A few notes about amp/head unit settings...

Alpine 9820 Head Unit:

1) Subwoofer OFF. There's an option to change the rear preamp out to subwoofer out. The head unit tries to do some low pass filtering and also provide level control through the tone/balance menu. I'd rather set the levels and crossover through the amp.

2) Power OFF. This turns the head unit's power amps off... I assume that since this reduces the load on the internal power supply, it means the preamp outputs will have better fidelity.

3) MX Mode OFF. What on earth is this anyway? Some sort of "loudness" processor. Yuck.

4) Tone Control to DEF (defeat). Disables all the tone controls, and MX Mode. I suppose this overrides 3) above anyway.

Alpine PDX-4.150

Channels 1 & 2 (Focal front and back speakers): Since the fronts and backs are in parallel, there's currently no way to set front/back balance. That's OK, it sounds perfect to me. I suppose a high wattage L-pad (or high wattage resistors) could be used in series with the direction that needs to be attenuated. The amp gain is set to nominal, filter to HP (high pass), and the crossover to ~100Hz.

Channels 3 & 4 (Stealthbox subwoofer): Amp gain is set to nominal, filter to LP (low pass), crossover set to ~100Hz, input channel to 3/4.

This is what I've come up with in a few hours of playing around. I may try to get some audio reference sources, measure levels with my dB meter and try for something more scientific. Or, I may just drive around and enjoy it!!!

Pic 1) Finished shot of the Stealthbox.

Pic 2) Settings on the amp.
 

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Thanks, I'm headed out to the garage to complete the install now. A 5 channel PDX, mmm? Possible future upgrade :drool:
I thought there already was one: 4x75/1x300
:shrug:
 

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Finally got around to a proper mounting bracket for the amp. 1/8" thick aluminum bracket tapped for the amp's mounting screws and attached to plastic firewall cover with fender fasteners. That completes the job.

Pic 1) "Custom" bracket.
Pic 2) The amp mounted to the bracket.
 

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