one approach for a 3 speaker dash on 70 Challenger

[dakota]

I'm putting this post in for anyone that might be considering a 3 speaker dash.   This one happens to be for a 70 Challenger.   

Although they came from different sources, the pair of 3.5" side speakers and the center 4x10" speaker all were made by Custom Autosound.

The small speakers: http://www.classiccarstereos.com/category/1970-1981-Camaro-Speakers-Mono.html

Look at the list for speakers that end with "1013" - there are two choices.  The speakers are easily removed from the metal brackets shown in the pictures.

The larger speaker:  http://www.cjponyparts.com/catalogsearch/result/?q=4x10+speaker

Yes, I really did buy parts listed for a Ferd and a Chebby for my Mopar.  I will go do penalty pushups immediately after finishing this post.

There is also an option to put in a pair of small speakers in the 4x10" space.  There is a person on "forabodiesonly.com" (" '74 Sport ") that sells these adapter plates for $26 including shipping.   This link should work to get to one of his posts:

http://www.forabodiesonly.com/mopar/showthread.php?t=166060&highlight=speaker


The main limit to finding a small speaker that will fit in the stock side speaker covers is the height of the center the speaker.   The options for 3.5" speakers shown above will fit, BUT you'll need to shave about 1/8" off of the paper material around the top of the speaker to fit it inside the speaker cover.  I used an Xacto knife to do most of the trimming and then a hand-held grinding stone to smooth things out.  I only stabbed myself once with the knife so I wasn't too bad.


No modifications were needed to fit the 4X10 into the dash pad.   This is a "Dual Voice Cone" (DVC) speaker so it is wired in like two separate speakers.  This speaker fits fine under the stock center speaker cover.

The dash frame had to be cut underneath the mounting locations all of the speakers.  This is necessary to fit the larger magnets that come with the modern speakers and/or the wiring terminals.   I used a jig saw with a metal cutting blade to do most of the trimming followed by a Dremel with a cut-off wheel for the hard-to-reach stuff.   If I had a body saw, that would've probably worked best.   I think I saw some posts about people who did some cutting with their dash pad mounted, but that would've been a major PIA.   If you're thinking about doing this, do it with the dash frame and dash pad out of the car.   

These pictures show the difference between the speaker that was in the dash (not stock, but probably the same size) and the dash frame after cutting.

[dakota]

Here are pictures of the small speakers that go on each side.   The close up shows the modification to the top of the speaker to get it to fit into the stock speaker grill cover.

[dakota]

The dash frame modification for the passenger side small speaker was pretty straightforward.   It took a bit more cutting to get the driver side small speaker to fit, as a port of the frame underneath had to be cut out too.   Best I can tell, this additional cutting will not be a problem when it comes time to mount the switch bezels, but if it is... well, that's just one more problem to deal with along the way.

While trimming the metal on the driver side area, a small spot (pinch?) weld broke where two pieces of metal overlapped.   This was a relatively quick repair using a drill and then tack welding the two pieces back together.

I wasn't happy with how the paint on my dash frame held up as it got scratched just moving it around in my basement.   It will be heading out for powder coating shortly along with the ashtray and the glove box door.

Last thought:  the stock grill covers I bought don't seem to fit the profile of the dash pad that I have.   Knowing what I know now, if I were to do this over again I would probably just stick with the single speaker opening style of dash pad.   At the time I bought my dash pad, I didn't realize there were dual voice cone speaker options or the adapter plate to allow for a pair of speakers to go in the same space.

I'll post pictures of the installed version of all of this when it's done.

[dakota]

One last pic showing part of what had to be removed from the dash frame to accommodate the driver side speaker magnet.

[70chall440]

same thing that I did.

[PlumCrazyChris]

Nice writeup, I did the same thing in my last two Challengers.  One thing that really makes a huge difference is to wire it with a crossover like they did at the factory.   With bass in the center and trebled on the sides.  What a difference.   
My current car didn't come with a 3 speaker,  but the hole is there in the metal from the factory.   So I cut out the dash pad foam and trimmed the frame as you show.  Then put a dash cap on with the 3 spaker layout.  The outside speaker covers are like hens teeth, so I used the covers from a Cordoba.  The curve is not exactly the same, but only I know, well I guess you do now...

Rock on!