Volvo 850 sedans have these rear speakers that are approximately 6" by 9", but in a way that is completely incompatible with standard "6x9" speakers (which are too large). They are also 8 ohm impedance which means you can't really use standard car audio speakers anyway.
This wouldn't be a big deal except for the fact that the magnets tend to fall off of the speakers in dramatic fashion if they don't blow entirely, most of the ones left in junkyards are already bad, and no more are being made by Volvo. So, I want to figure out an alternative.
I am trying to come up with a basic adapter plate that could be made out of flat acrylic (or something else???) and let me install a common Parts Express 6" 8 ohm driver. I took a bunch of pictures and drew the thing up on a piece of paper but have no idea where to go from here. Unfortunately I am now Apartment Living™ or I would just trace it onto a piece of balsa wood or something and go at it with some power tools. That being said, it would also be nice to have a nice finished piece fabricated by someone who knows what they're doing.
Ideally I would like to make some kind of CAD file or technical drawing that I could share with other Volvo guys to, you know, "give back" to the community and all that but that's not my primary concern.
Fabricator types, where should I go from here?
I would think there has to be some sort of adapter ring to make a standard sized speaker fit in that hole. I usually turn to Crutchfield for that sort of thing. They have a pretty thorough range of replacement stereo equipment.
This is too simple to resist... I'll make you a CAD file after I'm done with dinner, then I'll show you how to get it laser cut for a few bucks.
Just to be sure: Your hole dimensions are from center to center, right? Or are they from edge to edge? I'll need a diameter for the holes and a radius for the fillets, too.
Mr_Asa
UltimaDork
11/14/22 7:43 p.m.
Tom Suddard said:
This is too simple to resist... I'll make you a CAD file after I'm done with dinner, then I'll show you how to get it laser cut for a few bucks.
Might as well introduce him to SketchUp or some other easy CAD program to do the first part. Sounds like a decent article to go with the lathe/machining content
rustyvw said:
I would think there has to be some sort of adapter ring to make a standard sized speaker fit in that hole. I usually turn to Crutchfield for that sort of thing. They have a pretty thorough range of replacement stereo equipment.
Believe me, there is not. There's a reason that Volvo guys grab every single decent set of these they can find in junkyards. Not a single measurement on my drawing matches up to any standard speaker size.
Tom Suddard said:
This is too simple to resist... I'll make you a CAD file after I'm done with dinner, then I'll show you how to get it laser cut for a few bucks.
Just to be sure: Your hole dimensions are from center to center, right? Or are they from edge to edge? I'll need a diameter for the holes and a radius for the fillets, too.
That would be incredible! Hole dimensions are center to center (roughly taken with a tape measure so not very exact but it should be close enough). Screw hole diameter is approximately 3/16". I have no good way to measure the radius but they all seem consistent and they are radiused around some 1/4" diameter holes for the grille pegs if that helps.
Is there a wood version of SendCutSend that could make it for you with a CAD file?
Mr_Asa said:
Might as well introduce him to SketchUp or some other easy CAD program to do the first part. Sounds like a decent article to go with the lathe/machining content
I actually tried to do this myself with the web version of SketchUp that you can get for free and I was going absolutely mad trying to get it to cooperate. I'm somewhat well-versed in Illustrator and found SketchUp to be an order of magnitude more difficult to work with. I was just going to resort to mocking it up in Illustrator with dimensions marked but figured I would ask here if there was a better way before I went through the trouble.
eastsideTim said:
Is there a wood version of SendCutSend that could make it for you with a CAD file?
SendCutSend is actually who I was going to go with if I could come up with an appropriate drawing. I was thinking ABS or black acrylic would be ideal.
Yeah, and SendCutSend does a few types of fiberboard now. That's who I was going to recommend.
Okay, here's a DXF with your dimensions:
https://www.dropbox.com/s/bdiv082t3c0tlno/Volvo%20Speaker%20Adapter%20DXF.dxf?dl=0
And here's a link to the downloadable Fusion360 file so you can tweak it later:
https://a360.co/3hJXkbu
And here's a quick screenshot of the sketch so you can check my work and make sure I didn't mess any of them up. I added .150" fillets after the sketch phase so I wouldn't lose the constraints.
I wouldn't use acrylic, it'll be too cracky. I'd use thin plywood, which is super fast to cut with a laser. When Tom's done with that drawing, I can zap a couple out for you in no time.
Looks like it's about $21 to get one made from .234" ABS:
Keith Tanner said:
I wouldn't use acrylic, it'll be too cracky. I'd use thin plywood, which is super fast to cut with a laser. When Tom's done with that drawing, I can zap a couple out for you in no time.
Or, yeah, there's a reason stereo people use so much plywood. That's a solid offer.
If you can get a flat pattern of the original (trace it if you can), scan that and bring that into cad for far more accurate measurements.
also this is a good use of a 3d printer. Not that it's the ideal manufacturing method, just that it's such an oddball need. But if Keith is going to laser some... sweet
Fusion is so pointlessly overkill. Here's what it will look like if you ever drop it in a town square:
I should probably walk away from the computer now.
Before you get wrapped up in a fabrication job, you might ping Crutchfied and see if they have anything off the shelf. They usually do.
Oh my god, you guys are incredible, this forum is incredible, you saved me so much time and effort! THANK YOU TOM! (Anywhere I can send you some beer money for your time, perchance?)
I have been meaning to pick up some 3D modeling skills but I am currently trying to learn a bunch of other stuff for work and the time is just not right. The speed and efficiency with which this was knocked out though convinces me it's within my grasp.
Keith, if you're willing to burn some out of plywood, I would also happily send you some beer money!
jwagner (Forum Supporter) said:
Before you get wrapped up in a fabrication job, you might ping Crutchfied and see if they have anything off the shelf. They usually do.
This was already asked - they don't. This is a bespoke speaker that was only ever used in a couple of Volvos and Crutchfield's recommendation is "throw everything out and do a full custom install". I am here because I have already tried and failed to skin this cat with two different speaker adapters that seemed "close enough" that were far enough off to not be worth the time.
3mm hardboard. I've got some 3mm ply as well, but this stuff is pretty solid and possibly more dimensionally stable as long as it's kept dry. I'll need an address :)
Glad I could help! Don't feel obligated, this was a simple project that took me maybe 10 minutes, but I also won't say no to beer money if you really want to. My venmo and PayPal is my first and last name with no space, or you could just subscribe to GRM+ which will turn into beer (and mortgage) money for all of us on staff. 
Hope it works out!
In reply to Keith Tanner :
Holy crap this has to be a new record right? The forum just went from problem to finished part in what, an hour?
In reply to Tom Suddard :
Hey, I had to finish work :)
Plywood. I do like this better. Takes about two and half minutes to cut one.
You're really not helping me resist buying a laser.
