2006 A4 Avant Build.

[naiku]

Now that the subwoofer enclosure is pretty much done, the next thing is to relocate my amplifiers and DSP. The DSP should hopefully be fairly simple as it is small enough that I could leave it where it is, but would prefer to mount it behind the door on the right of the trunk. The amplifiers I am hoping to install where my subwoofer was previously. So far I have cut out a wooden template to attach the amplifiers to:



There is not a huge amount of room, but hopefully just about enough that I can fit the 2 PDX amps. The decision I am currently faced with is which way to orient the amplifiers. Ideally I wanted to mount them diagonally with the controls facing outwards in case I needed to make adjustments. While I may eventually do that, given that once I set the gains I rarely ever need to touch the controls it may be more trouble than it is worth. Ideally, I would like the wires to come out the bottom:



But, that is going to depend on how much room both the plugs take up and how flexible the wiring I am using will be. There is less room where the top amplifier will be mounted as I had to cut about 3/4" off to fit under a bunch of stock wiring that I can't move. It would be nice if I could rotate the Alpine logo to face upwards, no I won't see the logo with the door closed, but for some reason I would like it to face the right direction, doing that though the wiring would come out the to



The final option is to mount them sideways, with the wiring either coming out the back or the front, I don't know that I have the vertical room for this though so am not sure if this one is actually going to work:



At the moment I am leaning towards having the wiring come out the bottom and be neatly bundled together and either go through a cut out in the board to the space behind it before routing over to the distribution block or bunched together and go either back or forward and then over to the distribution block. If all goes to plan I want to have made a decision and have them mounted by tomorrow evening, then mount the DSP and distribution block to the opposite side Wednesday.

[naiku]

Not much of an update, placed the amps and started wiring them up:



Went with this orientation for simplicity sake, the wiring has to come out that direction so it saves me having to add extra bends to the wiring. Also mounted distribution blocks:



Annoyingly I was about 6" short on the power and ground wire I bought, so for now have 1 run of 4 gauge and another of 8 gauge. I ran 8 previously with no issues so may leave it, but I may also order another length of 4 gauge at some point to swap it out. Kicked myself for that one, did not take into account that one amp would be slightly further when measuring. Hoping to run speaker wiring later today.

[chithead]

That is great that they fit in an easy to mount and access again orientation!!!

[Babs]

Annoyingly I was about 6" short on the power and ground wire I bought, so for now have 1 run of 4 gauge and another of 8 gauge. I ran 8 previously with no issues so may leave it, but I may also order another length of 4 gauge at some point to swap it out. Kicked myself for that one, did not take into account that one amp would be slightly further when measuring. Hoping to run speaker wiring later today.

Looking good.. I suggest ties with screw holes for mounting to your boards, etc. Nice strain-relief work to immobilize the wiring. Too bad they don't make a wire stretcher huh.

[naiku]

Once all the wiring is in place I plan to use a bunch of ties to hold it where it needs to be, thinking of at some point picking up some split loom to bunch various different things together as well. Really trying to avoid the rats nest I had previously!! Not yet 100% decided on where I want the DSP to go, I had thought of mounting it in the same location as the distro blocks, but there is no real mounting point up any higher and I don't want to interfere with the fuel door opening mechanism. So, I may leave it where I had it under the floor, especially as it makes it very simple to access and plug in the USB cable.

As for the wire stretcher, yep, definitely wish I had one of those. It's literally a few inches short. I was all set to pull it through behind the spare wheel, got one run pulled, cut it for the first amp, held it up and just knew it was too short. See the little vertical lip in front of the distro blocks? That's about where it runs out of length!!

[naiku]

Put everything back together last night and during my lunch break today, thanks to @chithead for the RCA. I may drill holes through the board and route them through to the back at a later date, but needed the car back together for tomorrow. There are a couple other small things I want to tidy up, but don't have what I need on hand so they have to wait. The Helix stayed under the floor board and is now bolted down.



There is a little bit of play in the board the amps are on towards the rear, no more than a quarter inch rotation on the vertical axis as it is only bolted at the front. Trying to figure out a way to also bolt it at the rear, but there is not much currently there. Tomorrow I need to drive somewhere, so can see if they move much at all and to make sure everything else stays in place.

Trunk views, nothing to see here:



So after putting everything together I had about 10 minutes left of my lunch break, jump in the drivers seat after reconnecting the battery. Look over and.....



Oops!! Haha luckily I had not yet put the drill away so quickly put the sub back in the enclosure. Definitely need to at the very least modify either the phase or time alignment of the sub, it's moved about 18" forward from where it was and if I lean forward in the seat the bass gets noticeably louder.

I do now have a question, since my woofer and port are firing down into a void beneath the floor. Should I create some kind of opening in order to enable the sound to reach the cabin? The area the sub fires into is not sealed, but any openings are going to be fairly small (essentially gaps between the back of the seat and the floor type of thing). If I need to make an opening, what sort of size would that need to be?

[naiku]

While driving the car today I noticed I had developed a slight alternator whine. Very quiet, but noticeable especially between songs. Took the trunk apart, cleaned the ground spot again and also moved the DSP ground in the distro block to share with an amp. Started the engine briefly and the noise was gone. Put trunk back together and fire up REW.

Started level matching and noticed my left mid was about 10db lower than the right. Flipped the phase in the software made no difference, went to flip at the amp but first figured I would swap RCA left to right. Sure enough, the right mid was then quiet. Hooked up a short RCA and both play the same level. Going to pick up a new cable tomorrow.

Also noticed plenty of rattles outside the car, may leave those, but I have a rattle in the driver's door which I think is the door handle. I hear it outside and inside the car, just not sure how to stop it inside the car.

Gave things a listen briefly, though, at this point I think I just need someone like Erin or Steve to give it a listen and tell me what needs tweaking as I am at the limit of my current knowledge. Sounding pretty good though.

[chithead]

Oh man, I'm really sorry about that RCA. Guess it's days were numbered with that one plug damaged

[naiku]

No need to be sorry, the other one works perfectly and I appreciate you sending them both.

[naiku]

New RCA connected and started tuning last night, first re-checked time alignment, then level matched before making a couple tweaks to my EQ. Here is where I am at so far (Blue line is left, right is red)...

Tweeters:


Mids:


MidBass:


All Left and Right seperately (no sub):


All with sub:


I don't think it looks too bad, my left midbass needs the most work. Not really sure why it is such an odd response compared to the right, but that is likely where I will focus first. Then I will see if I can do anything about the slight dip at 400Hz (I think that is right at my crossover point, so should be fairly simple to cure).

Thoughts? Suggestions?