SpeakerTalk

[Dikirok]

Hi Again

Anyone tried to aquire or manufacture a new set of front covers for your 104aBs? The foam on mine long since disintegrated.

I think I could knock something up with some acoustically invisible fabric and a little wooded frame. Anyone else tried? What did you learn?

Ta muchly
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Richard Newbery

[proffski]

Yep! My woodworking skills are rubbish, great for a speaker builder entusiast! The small size frames I tried to build for 104aBs warped whilst drying.
In the end I bought foam from Falcon Acoustics and did some scraping with a stanley knife. So far so good! If you do not the drive units touch the foam at highish listening levels.

[ColinR]

In the U.S. a good source of foam of the right thickness, is that used in air conditioning units .

[larnerp]

My father and I both have Kef 104s (his are 104aBs and mine are 104s). Both have said goodbye to their foam fronts years ago, and we have discussed various ways to resolve the problem.

The first design was a wooden frame made from 4 strips of 1" x 1/2" wood to form a rectangle, covered with acoustically transparent cloth and fixed with velcro. Problem was that the tension on the cloth caused the frame to warp. Back to the drawing board.

The second design was a piece of 1/2" MDF with holes cut for the drivers, cover in cloth and fix with velcro. Worked but there was some reverberation caused (we think) by the small gap between the MDF and the front of the speaker cabinets. Back to drawing board.

The final design was made from a piece of MDF, but with a big square hole cut out the middle leaving a frame about 1" wide all the way round. The MDF was covered with a layer of 3mm foam, then covered with cloth and stapled onto the back. The foam gives a soft feel to the front. If you get the dimensions right and there is no need for the Velcro - the frame fits in the recess perfectly snugly.

We've been thinking about manufacturing these - would there be a market? What price would a 104 owner pay for a pair of these? Any views?

[proffski]

The Air Conditioning Foam seems like a great idea.
I'd be worried about vibrations and diffraction effects with a frame, I'll stick with the foam methinks...

[larnerp]

Yes, I was a little worried about vibrations from the frame too, but I can't hear any at all.

I think it may be that design 3 fitted so snugly into the recess on the front of the speakers that it has no opportunity to vibrate, and the distance from the nearest driver to the edge of the frame is too much to allow any vibration behind the frame.

The best installation would probably also include the removal of the velcro from the front of the speaker cabinet to allow the frame to fit flush with the front of the speaker cabinet.

[proffski]

Of the two samples I've owned the velcro falls off anyway leaving a white goo behind. Easily removed...