How to Build a Dolby Dash for your 850!


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I've been sitting on the parts to do this for a few weeks and finally got down to the basement and got to work last night.  Have about two hours in this project so far, guessing I probably have about that much left once I figure solutions to the problems I'm currently bumping into.  Despite these issues, this whole project is still WAY easier than I expected.

What do you need:


  • 850 dash pad
  • x70 center speaker and grill
  • The screws and clips that hold the center speaker into the x70 Dolby dash
  • A piece of paper

What it turns out you DON'T necessarily need (although it was helpful mostly to study in my case):

  • The part of the x70 Dolby dash where the center speaker attaches.


Tools you'll need:

  • Jigsaw
  • Jeweler's bow saw (or similar)
  • Hand drill
  • X-Acto knife (or similar)
  • Sandpaper
  • Flat bastard file (or similar)
  • T25 Torx Driver
  • Scribe
  • Pencil(s)
  • Scissors


So here's the deal: believe it or not, the x70 Dolby dash is just a regular x70 dash pad that Volvo literally cut a hole in.  Yep, that's it.  There is nothing special about the moulding.  This is fantastic because cutting holes in stuff is pretty easy if you ask me.  Check it out:




The edges are still rough!

Then it looks to me like they used a hot object and pressed it in the foam to create the depression that the whole speaker unit sits in.  This is a problem if you're trying to do this in you're basement, because you don't have this plate.  Neither do I (which, at this point, appears that it will be the only real issue with this project), so we're in this together.




Furthermore, the 850 dash pad is of a significantly different design than the 850 dash pad so, even if you did have this tool, I'm still not sure it would work.  As you can see in the photo, the layer of foam is much thinner on the x70, and, as you can't see, the plastic covering on top is much more rubbery and stretchy on the x70 pad than the 850 pad.




This is a bit of an issue because it prevents you from installing the speaker into an 850 pad exactly the way Volvo did in a x70 pad.  The solution to this is (currently working on the solution to this, stay tuned).


1.  If you have access to a Dolby dash, trace around the inside of the opening to make a template.  If you don't have access to one and there is interest in others doing this, I may make a drawing of this for you guys.

2.  Tape the template to the bottom of your 850 dash pad and scribe around it (couldn't get anything in the shop to write on this plastic).  Don't grab a reject invoice from the family business out of the recycle bin to make your template from if you're planning on posting a pic of it to the internet; saves time if you don't have to scribble stuff off the paper with your scribe and then blur out the stuff your forgot.




3.  Check for clearance issues with the center speaker mounting tabs on the front (ideally, you will do this before you scribe around your paper template).  I tried to put it in the same place it was in on the x70 Dolby dash, but it turns out that this won't work because there is a clearance issue with the mounting points for the dash pad.  I decided to move it back ½" rather than put it off center.




4. Using your X-Acto knife (or similar), Cut a hole through the foam on the top of the dash pad in the area that you will be cutting out for the center speaker.




5. Create a hole to put your jigsaw through in the same location you just removed the foam from.  I used a small drill and drilled several holes around the edge of this now larger hole and cut through the remaining plastic between the holes with the X-Acto knife.  Not having to drill through foam makes life 1,000,000x easier in this step.




6. Using your jigsaw, cut around as much of the area as you can.

Adjustable speed antique Black and Decker jigsaw FTW.



7. Depending the geometry of your jigsaw and where exactly you place your center speaker, there may be areas where it is difficult or impossible to cut with the jigsaw.  Use your jeweler's bow saw (or similar) in these areas.





8. At this point, you hopefully have a hole that looks something like this.  Use the sandpaper to clean up the edges of the hole.





9. Note how the front of the center speaker attaches to the x70 Dolby dash.  The hooks on the front end of the speaker clip in underneath the dash pad.  This means that, at least in the case of the x70 Dolby dash, the thickness of the dash pad where the front of speaker sits is critical.  Unfortunately, this is a bit of a problem given that the foam and covering material on the 850 are completely different from the x70.  Stay tuned for a solution to this and how to finish off making your Dolby install look factory!


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Welcome to How to Build a Dolby Dash for your 850! - Part II.

Materials and tools list updated in the original post.

9. (cont'd) So, what was the clever solution to the dash pad thickness problem? Well, given that creating the depression that the stock x70 Dolby dash has was clearly not realistically possible with the equipment available to me in our basement (which is quite extensive), I decided to try just pushing the feet on the aft edge of the center speaker unit into the foam of the dash pad. Well, guess what? It worked! After you spot the holes by just pushing the feet into the foam, you will want to get in the holes with the X-Acto knife to clean out some of the excess foam. This will prevent the compressed foam from pushing up on the outer covering of the dash pad making it look crappy.


10. At this point, it became clear that I needed to create the mounting points for the screws in the forward edge of the center speaker. This is epically easy, just cut back the foam, spot and drill pilot holes through the plastic, and install these clips. I got these off of the part of the Dolby dash that I have. You could probably easily substitute ones from somewhere else. I'd bet that the Dolby dash isn't the only place these exact ones were used.


11. More clearance problems, these bosses the screw holes are located in are supposed to sit on the hard plastic part of the dash pad on the x70 Dolby dash.

28616423153_4e9d06d6c8_h.jpgIMG_9625 by Jared R 945, on Flickr

12. Easy solution, just trim back the foam padding underneath these bosses. Except there was another problem. These don't actually sit on the plastic as they should because of the disparity of thickness of the dash pads and the fact that I elected not to create the depression that the speaker is supposed to sit in. It's another easy solution, though: you just need a spacer. I was going to be fancy and grab some delrin rod and turn in down to the proper diameter and then drill a hole in it, but my dad was using the lathe so I abandoned that and just hit up the washer bin instead.


13. Install your center speaker!


14. Remove some material from the aft right corner of the center speaker grill/cover. Unfortunately, I didn't take a picture of what it looked like with the first install, but the contour of the x70 dash is obviously considerably different towards the right edge of the vents. I used the file and then some sandpaper to cut down that corner a little bit so that it would fit. You don't have to take off much to make a big difference, so you should make test fittings as you go.


15. Install your center speaker grill. Congratulations, you have successfully completed your 850 Dolby dash. Enjoy your Dolby surround sound!!!

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Nice Job! It's good to see someone tackle this.

I'm guessing that you have another speaker, though.

The one in your pics is missing a pretty good chunk 

of woofer magnet. That looks like a first run driver.

Later center channel drivers had an improved woofer

magnet design with a structural reinforcement bolt.

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  • 1 month later...
On 8/26/2016 at 2:05 AM, BEJinFBK said:

Nice Job! It's good to see someone tackle this.

I'm guessing that you have another speaker, though.

The one in your pics is missing a pretty good chunk 

of woofer magnet. That looks like a first run driver.

Later center channel drivers had an improved woofer

magnet design with a structural reinforcement bolt.



Yes, I do have two speakers.......I got two busted ones from gmsgltr and built one good one out of them. This speaker is what was left after that was done.

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2 hours ago, JaredR1 said:



Yes, I do have two speakers.......I got two busted ones from gmsgltr and built one good one out of them. This speaker is what was left after that was done.

So, is the one in your pic the one that's installed?

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On 10/21/2016 at 11:30 PM, BEJinFBK said:

So, is the one in your pic the one that's installed?

Some parts of that speaker got installed.  I thought I had gotten the other one that the magnet hadn't fallen off of good to go until I tried to put it all together and some of the mounting points were busted off.  I had to swap that speaker into this housing iirc.

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