Speaker grilles and baffle finishing....

[Jerms]

I've seen some posts by XRK971 regarding green dish washing pads and off-axis dispersion. Is it a good idea to maybe incorporate these in some form of speaker grille/cover?

Also, wondering how to finish the baffles of my Woden Redeyes. Currently they resemble a fight between MDFs in a glue factory.

 

[Jerms]

Speaker grilles will either be cutoff circles/elipses or a "wrap-around shades" type. Either way I've bought pegs/sockets and grille cloth. Main cabs will be spray painted once I get the base/undercoat smooth.

For UK buyers, you may want to look at some of the items sold by CPC. Major plus is £5 order gets free delivery.

 

[chrisb]

For grilles as small as the Redeyes would require, I'd suggest considering using little neo magnets mounted flush with the baffle face and frames. Thanks to some prodding from Dave a few years ago, I've been using 1/4" dia by 1/2" long "rod" magnet from Lee Valley.

They take no more accuracy in drilling holes in the two mating surfaces than pegs/sockets, automatically align the grilles in place , will be completely "stealthy" if the speaker is veneered - and my most favorite part is don't break - ever tried to replace broken post or cup without damaging a painted or veneered baffle? They're certainly one of my pet peeves, along with cheap spring loaded terminals on a hot-glued masonite / XO board.

 

[Jerms]

I may have mentioned elsewhere that I'm clumsy.

I'd still probably want to use some form of mechanical approach. Not rely solely on the magnets.

I have some 8x2mm neo magnets left from my car phone mount project. I can use some of those if the ordered pegs/sockets look bad.

 

[chrisb]

Fair enough - but with the size likely involved for the Redeye, a total of 8 little neo magnets per side will have a lot of holding power (approx 3 lbs per magnet), and the worse that can happen if hit the wrong way is that the grille will slide off.

If making a small wood frame for grilles, both types require the same accuracy in drilling holes in the mating surfaces . I stack and tape the two pre-cut frames, drill them on the drill press, then tape each on the enclosure, and drill again- either on a drill press for small ones, or by hand on enclosures too large for the press or with sloped / curved front baffles. Set a depth stop for approx .5mm deeper than the magnet thickness and tap flush with a block of scrap wood. Once the frames are actually cut, it takes almost as much time to describe it as to do the work. Of course unlike male / female fastener types, you do need to pay attention to polarities.

I've also used self-adhesive velcro circles on light grilles - no holes at all, and more than sturdy enough for this application .

 

[Jerms]

Thought I'd update this....

As they are now.
http://www.diyaudio.com/forums/construction-tips/288453-woden-redeye-build.html#post4708422

Criticisms....

Grilles: I went a bit belt and braces for the grilles. I was concerned with have enough "meat" to them to profile them whilst allowing depth enough to clear the roll surround and driver excursion. Whilst I rounded the tops and bottoms over, I should have stuck a tighter radius in to blend with the sides rather than leaving the corners pointy. So they stick out a little bit more than is optimal and cut a sharp profile from some angles. It's possible I'll redo them or reprofile them to soften.

Baffle and finishing: I don't think MDF likes me. I tried to prepare the surface with dilute PVA to stabilise it but every light sanding brought more furry bits of MDF standing up the next time I applied PVA/undercoat or paint. I've since read a little more on finishing MDF. I think I'd start with a high VOC polyU varnish (maybe dilute) to coat all exposed ends and cuts. Then use the lightest touch possible to flat it back. Using a finer grade of sand paper or wet/dry.

 

[Fivetide]

I live in Preston !! what an awesome post.. CPC are like 5 mins up the road.. via horse and cart of course

 

[Jerms]

Fair enough - but with the size likely involved for the Redeye, a total of 8 little neo magnets per side will have a lot of holding power (approx 3 lbs per magnet), and the worse that can happen if hit the wrong way is that the grille will slide off.

If making a small wood frame for grilles, both types require the same accuracy in drilling holes in the mating surfaces . I stack and tape the two pre-cut frames, drill them on the drill press, then tape each on the enclosure, and drill again- either on a drill press for small ones, or by hand on enclosures too large for the press or with sloped / curved front baffles. Set a depth stop for approx .5mm deeper than the magnet thickness and tap flush with a block of scrap wood. Once the frames are actually cut, it takes almost as much time to describe it as to do the work. Of course unlike male / female fastener types, you do need to pay attention to polarities.

I've also used self-adhesive velcro circles on light grilles - no holes at all, and more than sturdy enough for this application .

Oops, maybe I should have replied to this..... In fairness, it took me a while to gather materials and do it.

I have no drill press in my man-cave.... Table saw made from a circular saw for roughing and a router and router table for trimming etc. Plus the usual assortment of power tools.

I didn't trust my accuracy with a "freehand" power drill. So I made a jig.
Two plates to lie on baffle with 12mm overhang each side. with holes drilled 6mm (grille pegs take 6mm).
Two rails along the sides of the speaker to hold the plates together and align along the baffle.

For the 10mm holes needed in the baffle, I used a "step drill" set to gradually increase the 6mm holes, then finished with a 10mm drill.

It became obvious the sockets needed recessing as the grilles stood off the face a comedy distance., probably 5mm. I did that "freehand" with a 15-16mm bit in the router. With a bit of wood filler around some of the edges it came out fine.

I could have spent a little more time preparing the finish but trying to get the cut ends of the MDF smoothed "irked" me too much in the end. Next one will have 45 degree angles or will have the edges made out of real tree.

J.