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-   -   Material for speaker grille frames? (http://www.diyaudio.com/forums/multi-way/230804-material-speaker-grille-frames.html)

Kooshball 25th February 2013 01:39 PM

Material for speaker grille frames?
 
I plan on making grilles for my speaker project and would like some advice on what frame material is ideally suited to the task. I am going to embed magnets into the baffle, behind the veneer so that they can be blind-mounted and plan to stretch speaker cloth over the frame to complete the project...other than that there are no special criteria.

I assume that plywood would work, but is it typically too heavy?

THX

pkitt 25th February 2013 03:04 PM

1 Attachment(s)
I like to use 3/8" (9 mm) Baltic Birch Plywood for grille frames which is available in several different sizes at Woodcraft. It's very rigid, and it's lightweight once you cut out most of it to clear the drivers. I also use magnets but instead of imbedding them into the baffle, I countersink them into the back of the grille frame with them aligned to some of the bolt/screw heads that mount the drivers to the baffle. I've attached a photo of the pair of grilles from my last project. It was a 2-way with an 8" woofer and I used four of the woofer's mounting screws for the magnets to grab.
Paul


Quote:

Originally Posted by Kooshball (Post 3385279)
I plan on making grilles for my speaker project and would like some advice on what frame material is ideally suited to the task. I am going to embed magnets into the baffle, behind the veneer so that they can be blind-mounted and plan to stretch speaker cloth over the frame to complete the project...other than that there are no special criteria.

I assume that plywood would work, but is it typically too heavy?

THX


lanchile 25th February 2013 03:08 PM

Floating Anti-Diffraction Grilles | Technology & Engineering | Polk Audio

Jim Griffin 25th February 2013 04:13 PM

For rectangular grills I use extruded aluminum frame material (for screen doors) from home supply stores like Lowes or Home Despot. This framing is 0.75" wide x 5/16" thick) and includes a groove on the rear side for rolling in a 0.125" diameter spline. On the baffle I too embed 0.375" diameter flat high energy magnets flush mounted under veneer or laminate. The frames are assembled with plastic corner pieces (buy these in the same section as the frame material). I glue 0.500" diameter flat magnetics into the corners of the plastic corners (careful to observe polarity so that these magnets attract to those in the baffle and use flat washers as spacers to raise the magnets to be flush with the frame). Cut grill cloth 2 to 3 inches larger than the finished frame in all directions. Place the cloth flat on a table and center the grill frame (rear side facing upward) on it. Now use a spline roller tool to press the spline and cloth into the groove on the rear side of the frame. Use your third hand to gently stretch the cloth and a flat bladed screw driver to work the spline/cloth around the corners. Once you have the cloth rolled into the groove, you can trim excess cloth and you are good to go.

The result is a lightweight frame which is attracted to the magnets in the baffle. With this technique alignment of the magnet holes between the baffle and frame is critical as the magnets are self aligning when they come together. I've made grills as large as 12" x 72" for line arrays with this technique.

You can also flush mount flat magnets into the baffle of speakers that are already assembled and use the framing material as well. Lee Valley has high friction vinyl disks that cover the magnets after you have glued them into the surface of the baffle.

soundchaser001 25th February 2013 04:56 PM

I have used finger jointed pine 1/4 round moulding with triangular gussets in the corners. Cheap and light.

cT equals piD 26th February 2013 01:33 AM

The last pair of grills that I made have sides of 1/2" X 3/4" softwood molding made into a frame by gluing and nailing to 2" X 2" X 3/4" pine corner blocks from dimension lumber. Be careful that the corner blocks are exactly square. Before building the frame, make a 1/16" deep groove halfway down each side piece of molding where the 1/2" dimension is front/ back.

After assembling the frame, stretch and staple the grill cloth in the grooves on all sides. Removing a few staples at a time holding the grill cloth in place, permanently attach the grill cloth to the frame with hot glue. After the grill cloth is permanently attached, trim off excess cloth with an X-acto knife along the bottom edge of the grooves.

Finally, make right angle sections of 1 mm X 3/4" wide strips of styrene and attach the sections to the lower exposed wood of the sides of the frame with super-glue. The styrene strips hide where the cloth is glued to the wooden frame with hot glue (ugly if left exposed) and also give the frame a plastic-look. I assume that you like a plastic-look.

That maybe isn't too clear, but it would take a high word-count and probably several photos to make it really comprehensible.

-Hey, I'm not getting paid to communicate this stuff.

Regards,
Pete

SRMcGee 30th December 2014 11:35 PM

Folks:

I'm planning my first speaker project (the Elsinore) and am considering how to build and implement an optional grille. Jim Griffin's approach seems reasonably simple to implement, but I'm considering an even more low-profile approach.

My current speakers are Egglestonworks Andras, which have very flat metal frames covered in a very thin grille cloth. There are two frames on each speaker; one is square and covers the woofer and the other is rectangular and covers the midrange drivers and tweeter. The frames, which are about 1/16" deep, are held in place with magnets imbedded under the speakers' veneer. I assume the magnets are neodymium. The metal used in the frame is painted black and given its rigidity and weight may be steel; the corners appear to be welded.

I'd like to duplicate the frames but don't know where to begin. Can anyone correct any observational errors I've made and/or provide guidance on how to build very slim metal grilles?

Regards,
Scott

Jim Griffin 31st December 2014 01:41 AM

A couple of comments on my grill design that I detailed earlier. My grill frames (5/16" thick extruded flat aluminum tubing used for window screens) have Neo magnets glued into the plastic corner pieces. The grill magnets are attracted (polarity must be maintained) to magnets buried under the veneer on the baffle. The grill cloth is wrapped around the frame and spline rolled into the groove on the back of the tubing.

We could focus on implementing a DIY version of the Egglestonworks design. To make a thin frame I suggest that we eliminate the magnets from the frames in my design and use steel flat washers to attract the baffle embedded magnets. We would need thin, light weight strips of say plastic, wood, or aluminum,etc. for the frame structure. Grill cloth could cover the frame and be glued to the back side of the frame. The washers could be attached via glue to the backside of the frame at the proper location. Notice that we would have a frame essentially the thickness of the strip material, the thickness of the washer and one or two cloth thicknesses.

Now the trick in all this is to select the frame material and perhaps some jigs to hold things in place during cloth wrapping and gluing.

sippy 31st December 2014 02:20 AM

You could use carbon tube ( used for arrow shafts / kite frames / aeromodelling) with plywood corner gussets holding everything in place.
Cut the tube with 45 degree ends and 'V groove' the plywood so the tube can 'sit in' and make nice profile.
Glue it all together with 24hr Araldite, held together with masking tape and pressed flat while curing out.
They won't warp unless you get your cloth tensions really screwy.

SaSi 3rd January 2015 12:16 PM

Plywood and mdf would do, although too thin an mdf panel and large cutouts for the drivers will make it a bit easy to break, even while stretching the cloth.

I've done one pair once, and I used 4mm plywood with routed edges to soften them. 1.5" borders around the woofers were the weakest point and they held up nicely.


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