New Style of Grill Cover... Minimize Bad Effects??

[mike1234]

I was contemplating negative effects of grill covers and ways to minimize them. Apparently, the worst offender is the frame, correct?

WHAT IF: One were to use a thin fabric such as black nylon stocking material and stitch the edges with a very thin stretchable cord to prevent fraying. Then attach one very small tube on each corner of the cloth. These would slip onto corresponding tiny steel poles on the corners of the baffle. The tubes would have tiny neo magnets glued to the inner bottom so they would stick to the steel poles.

This should nearly eliminate all issues with grill covers, right??

[depthsounder]

Sounds reasonable, if the purpose of the grill cover is to provide visual deterrence and to prevent dust accumulation rather than providing a physical protection for the drivers. One issue though, I would think that you would get a distinct X shaped pattern of the cloth if only the corners are supported without supporting the length of each side.

I can picture several similar configurations, such as using a curtain rod style support on the top and bottom of the enclosure to stretch the fabric.

I suppose that one could also tailor the frequency response of the speaker with the baffles in place. I imagine that if anyone will be demonstrating this technique, it will be Mr. Krutke, as he now has a (welcome) resident threat to dustcaps and tweeters.

-David M

[Æ]

WHAT IF: One were to use a thin fabric such as black nylon stocking material and stitch the edges with a very thin stretchable cord to prevent fraying.

The only good grille is no grille.
Yes, the best material would be the thinest possible.
I've often thought of using pantyhose material too. I envision myself going into a store and buying a few pairs of L'eggs. Opening up the packages and examining the material, all the while some curious lady shopper passes me by in the same isle and looks at me incredulously. No ma'am, they aren't for me! I need them for my loudspeakers.

I don't think you can serge, sew the edge of pantyhose nylon effectively. The only way to stop it from unraveling would be to hot melt/cut the edge. Heat seal it. I have some experience using ultrasonic welding to fuse the opposite ends of nylon printer ribbon together. The ultrasonic welder uses a big piezo electric transducer.

I was thinking of stretching pantyhose nylon over a plastic grille frame. Something like black ABS cut perfectly round with a router. After stretching the nylon across nicely, saturating the plastic with solvent cement. You wont be able to dissolve the nylon, but if you saturate the plastic with enough solvent cement, the plastic will get real soft and gooey and some of the goo will soak into the nylon weave. Wait for the solvent to dry, the plastic will harden mechanically fusing them together. Then trim the edges, removing the excess nylon.

[Todd G.]

What Mike is describing is very similar to the method used by most screen mfg's to stretch/secure the screen in doors and windows. In their case I think they use a groove and then press the screen into the groove using a rubber gasket ot rubber tube. The rubber holds the screen in place using nothing but compression. Before I spent too much time reinventing the wheel, I'd check out HD and see if the DIY screen kits they have couldn't be used to good effect. I think it would work.

[Æ]

What Mike is describing is very similar to the method used by most screen mfg's to stretch/secure the screen in doors and windows. In their case I think they use a groove and then press the screen into the groove using a rubber gasket ot rubber tube. The rubber holds the screen in place using nothing but compression. Before I spent too much time reinventing the wheel, I'd check out HD and see if the DIY screen kits they have couldn't be used to good effect. I think it would work.

I'm familiar with the concept, the rubber in the groove is called "spline" and the tool with roller wheels for pressing it in is called a spline tool.
Window screen looks really cheesy on a loudspeaker. Ha!

[mike1234]

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Sounds reasonable, if the purpose of the grill cover is to provide visual deterrence and to prevent dust accumulation rather than providing a physical protection for the drivers. One issue though, I would think that you would get a distinct X shaped pattern of the cloth if only the corners are supported without supporting the length of each side.

I can picture several similar configurations, such as using a curtain rod style support on the top and bottom of the enclosure to stretch the fabric.

Hmm... you're probably right. Maybe thin SS tubing along all four sides? OTOH, maybe the resulting funky shape would look kewl?

I suppose that one could also tailor the frequency response of the speaker with the baffles in place. I imagine that if anyone will be demonstrating this technique, it will be Mr. Krutke, as he now has a (welcome) resident threat to dustcaps and tweeters.

-David M

The only good grille is no grille. (I agree)
Yes, the best material would be the thinest possible.
I've often thought of using pantyhose material too. I envision myself going into a store and buying a few pairs of L'eggs. Opening up the packages and examining the material, all the while some curious lady shopper passes me by in the same isle and looks at me incredulously. No ma'am, they aren't for me! I need them for my loudspeakers.

Yeah, we audio geeks are just a bunch of pervs.

I don't think you can serge, sew the edge of pantyhose nylon effectively. The only way to stop it from unraveling would be to hot melt/cut the edge. Heat seal it. I have some experience using ultrasonic welding to fuse the opposite ends of nylon printer ribbon together. The ultrasonic welder uses a big piezo electric transducer.

I think there's a removable iron-on paper to keep cloth flat while sewing, isn't there? Geez... I don't want to go searching through sewing threads!!

I was thinking of stretching pantyhose nylon over a plastic grille frame. Something like black ABS cut perfectly round with a router. After stretching the nylon across nicely, saturating the plastic with solvent cement. You wont be able to dissolve the nylon, but if you saturate the plastic with enough solvent cement, the plastic will get real soft and gooey and some of the goo will soak into the nylon weave. Wait for the solvent to dry, the plastic will harden mechanically fusing them together. Then trim the edges, removing the excess nylon.

That's an excellent idea but I'm trying to eliminate the "frame" completely.

What Mike is describing is very similar to the method used by most screen mfg's to stretch/secure the screen in doors and windows. In their case I think they use a groove and then press the screen into the groove using a rubber gasket ot rubber tube. The rubber holds the screen in place using nothing but compression. Before I spent too much time reinventing the wheel, I'd check out HD and see if the DIY screen kits they have couldn't be used to good effect. I think it would work.

Close but not quite. I want to eliminate the "frame" completely or at least minimize its size to the point of having practically no affect on the sound.

[Todd G.]

There would be no frame, just a grove down each side of the speaker. The grill cloth would fold around the sides and be held in place by the spline, which was pressed into the grove by the spline tool. Thanks AE. All of this would be flush to the surface of the cabinet once in place.

[mike1234]

There would be no frame, just a grove down each side of the speaker. The grill cloth would fold around the sides and be held in place by the spline, which was pressed into the grove by the spline tool. Thanks AE. All of this would be flush to the surface of the cabinet once in place.

Ahh... okay. Please forgive my cerebral density. I suppose if one mounts the drivers deeply enough to avoid contact with the cloth it would work perfectly. Thanks!!

[Æ]

There would be no frame, just a grove down each side of the speaker. The grill cloth would fold around the sides and be held in place by the spline, which was pressed into the grove by the spline tool. Thanks Æ. All of this would be flush to the surface of the cabinet once in place.

If you can flush mount a woofer or tweeter why not a frame also?

My idea was to recess the woofer, flush mount and then make a rebate all around the woofer about the same thickness and width as the grille frame. The grille frame would be flush fit, it would fit right over the woofer.

The frame would be a ring that had a larger inside diameter than the outside diameter of the woofer. If you matched dimensions carefully, the finished ring with nylon attached would press fit into the rebate around the woofer and stay in place from the friction.
I hope I explained it understandably.

[mike1234]

If you can flush mount a woofer or tweeter why not a frame also?

My idea was to recess the woofer, flush mount and then make a rebate all around the woofer about the same thickness and width as the grille frame. The grille frame would be flush fit, it would fit right over the woofer.

The frame would be a ring that had a larger inside diameter than the outside diameter of the woofer. If you matched dimensions carefully, the finished ring with nylon attached would press fit into the rebate around the woofer and stay in place from the friction.
I hope I explained it understandably.

Yes, I like this idea!! Is it a problem with the cloth contacting the bass drivers on low notes or transients? Is it feasable to recess the drivers enough to prevent this or will that create new problems?

[Æ]

Yes, I like this idea!! Is it a problem with the cloth contacting the bass drivers on low notes or transients? Is it feasable to recess the drivers enough to prevent this or will that create new problems?

Yes, it would be a problem if the nylon/cloth/material were to touch the surround. It wouldn't be a problem with drivers that have a raised cosmetic frame or drivers that have inverted surrounds. I guess it kind of depends.

[jonpike]

If you can flush mount a woofer or tweeter why not a frame also?

My idea was to recess the woofer, flush mount and then make a rebate all around the woofer about the same thickness and width as the grille frame. The grille frame would be flush fit, it would fit right over the woofer.

The frame would be a ring that had a larger inside diameter than the outside diameter of the woofer. If you matched dimensions carefully, the finished ring with nylon attached would press fit into the rebate around the woofer and stay in place from the friction.
I hope I explained it understandably.

Cool idea...
I had thoughts on this I've never tried... (all my drivers go naked, thank you very much) Idea was to make a thin wire frame out of something, brazed or welded together, with a thin fabric stretched over it. Basically going for a minimum cross section of frame structure. Sounds a lot like some of the other ideas.

Combining the two would be good... problem with a minimal wire frame is, it isn't very strong. Having a say 1/4" wood base frame would make it much stiffer, but then you have a 1/4" step. But countersinking it flush takes that back away... and you'd have the best of both worlds.

[MagicO309d]

I was contemplating negative effects of grill covers and ways to minimize them. Apparently, the worst offender is the frame, correct?

WHAT IF: One were to use a thin fabric such as black nylon stocking material and stitch the edges with a very thin stretchable cord to prevent fraying. Then attach one very small tube on each corner of the cloth. These would slip onto corresponding tiny steel poles on the corners of the baffle. The tubes would have tiny neo magnets glued to the inner bottom so they would stick to the steel poles.

This should nearly eliminate all issues with grill covers, right??

I've been thinking about the very same concept except attached with grooved and polished aluminum stand=offs on the baffle to catch loops in the elastic seams instead of your tube aproach. Instead of 4 attachment points, I was also thinking 6 or 8 spaced around the baffle. If done with enough craftsmanship, it could provide an interesting floating appearence. A modification to this concept could include higher standoffs at select locations with elastic or cord between them for an interesting 3d effect on the floating grill.

Another approach for a floating grill would be to ask a metalworking shop to make rectagular frames out of stiff 1/8" wire stock. This would ensure a perfect result with minimum effort. An interesting modification to this approach would include having the shop bow the frames slightly for a curved floating effect down or across the front of the baffles. The curved floating grill may also work perfectly when integrated with a curved side panel cabinate too.

I've got to try these ideas on a future project as I progress with my skills!

[johnnail]

The most effective means of "minimizing grille impact on sonics" that I have seen to date would have to be examples of what Alon, and Definitive Tech speakers have. Def Tech and in some older Boston Acoustics speakers had the drivers flushed to a little bit below the surface, with the recessing being rounded and smooth.....the driver surround furthest protrusion is just below flush with the cabinet...and then the whole cabinet is fitted with a speaker cloth "sock" No frames. The top and bottoms are capped with some sort of panel, whether wood with finish or mdf with paint. Alon, as in the Alon 2 Mk2, used an open baffle midrange on a panel that is free-standing above the woofer cabinet, with tweeter mounted as well....they then used round doweling at the four corners of the bass cabinet that matched the roundover profile of the bass cabinet....and a permanent top plate well above the mid/tweet baffle. Then the whole speaker is covered with a grille sock. Either way worked quite well. Recessing the drivers isn't going to hurt the response if the transition is smooth and taken into account during crossover design. Another good grille implementation is the strings used on the Amati Homage line.

John

[mike1234]

Thanks all!! These are some very interesting responses. Two things I want to ensure, other than minimized sonic impact, are ease of installation/removal and longevity.

I like AE's idea to simply recess the frames around the drivers. That could be a very nice look.

John's sock covers are interesting but I think I'd like to minimize the size of the sock... maybe just use a stretchable material that wraps around the edge of the baffle where the sock slips into a side groove circumferentiating the baffle.

Another concept is to simply rabbit the edge of the baffle to accept a more conventional frame thereby flush mounting it.

These all accomplish the same sonic goals while providing different looks.