The 240 truck gets some sound system upgrades

[PapaSmurf2k3]

I suppose I should call this phase 1.5... phase 1 was to actually add rear speakers back to the vehicle after they got removed from the rear of the hatch.
So I've got this roll bar I put in to brace the chassis after the C-pillars were removed. There's a cross-bar at the bottom that's level with the rear of the vehicle, with the substructure for the deck running from the back of the vehicle all the way to this lower cross-bar.
So this left an area under the cross-bar that I could fit a couple 6x9s. I whipped up a bracket/plate dimensioned to fit the area in CAD, then had it CNC plasma cut at a buddy's shop.

I clamped it up and cleaned off some of the slag, as well as drilled the holes for speaker mounting, and welded in the weld-nuts:


The fit is good!
I can't remember if this is a pic of welding in the speaker plate, or the deck under the substructure... either way its in the same area:

Here it is, welded in, speaker mounted:


Anyway, I'd call that the end of phase 1.
After operating for a little bit, I noticed the speaker bracket had a LOT of vibration at higher volumes, and it didn't sound great. I added some bracing to the sides of the plate, which helped a little, but I still wasn't getting the performance out of the speakers that I was expecting.
Anyway, I don't know how I've gone through life not knowing about these speaker baffles that are out there.
https://www.amazon.com/050380-Boom-Spea ... er+baffles

It helps seal the speaker in a free-air setup, giving it some air spring, increasing the efficiency and bass.

It seems to work fairly well. I listened to the speaker at low to mid volumes while popping it in and out of the baffle housing and noticed a pretty solid difference.
So this concludes phase 1.5.
Next up, I'm converting the front speakers from 4x6s to 6.5s using the replacement brackets available all over the internet.
https://www.amazon.com/1989-1994-Nissan ... sx+speaker
I'll also be checking/verifying speaker performance and have some baffles for these already on hand. Hopefully everything will be satisfactory after that!

[centralcoaster33]

Wow, you do with metal what most do with MDF... Cool!

I saw your post elsewhere noticing the 6.5" cutouts in an Australian car (I think). I wonder if that sparked your latest stereo updates. I like 6.5" mids up front pretty nice. I like having tweeters in the A-pillar as well. Mines S14 though, so it's already set up for me. I hope your project continues to go well!

[PapaSmurf2k3]

Yup, that's what gave me hope for making the sound system actually sound acceptable. I had essentially given up on the idea if I had to keep the 4x6s ha.

[centralcoaster33]

Well, consider using those foamy things for the fronts as well. It will help the sound come from the speaker and not the rest of the door (a little). It will also prevent car wash or rain water from getting on the back of the speaker from the window sill (a big plus when spending money on decent drivers).

[float_6969]

Subscribed!

[PapaSmurf2k3]

Well, consider using those foamy things for the fronts as well. It will help the sound come from the speaker and not the rest of the door (a little). It will also prevent car wash or rain water from getting on the back of the speaker from the window sill (a big plus when spending money on decent drivers).

Oh yeah, I got the foamy things for the front at the same time I got them for the back.
I did the upgrade a little while ago, but then Carlisle happened so I didn't get to post the update, plus I didn't drive the car until yesterday since doing it.
Anyway, the damn wires in my door were super short so I had to make some jumper wires from the speaker to tie into the harness. I was training my liver for Carlisle at the time, so I was decently inebriated, and forgot to take a lot of pictures.

But that's what you get.
They definitely sound better than the 4x6s that were in there. I can crank the volume a lot more without hearing a bunch of distortion, which is really what I was after. Driving the truck with the windows down, no back to speak of (so, open cockpit), and loud-ish exhaust means the speakers have to do some work in order to be heard.

ALSO, I remember the 6.5" speaker adapter plates came with some speaker mounting hardware, but that s*** definitely wasn't going to work with the foam. The bolts were WAY too short, and were actually a machine screw with no freaking pilot on the front to aid alignment (super frustrating, especially when you're tipsy). I ended up getting some longer screws with a heftier thread and a pointed end. Something that you'd find in an interior or something. They worked a lot better.

[PapaSmurf2k3]

Alright I got some more pictures.
Here's what one of the doors had in there:


The wiring on this door was MUCH better/longer. Of course, by the time I got to that side, I found some wire extensions in the box that I could have used on the other speaker. OH WELL.

And there she is. The BoomMat didn't really seat as squarely as I wanted. This actually caused some of the ports in the speaker to be blocked by the foam, causing poor performance and somehow a rattle. I drilled the foam out by the ports and everything got better.
I also found some rattles in the rear speakers. Traced it to some excessive wire that was inside each of the foam housings. I just tugged on it from the back and it all went away. Good stuff now.