Altec 420 Dust metallic dust caps removal.

[charly1944]

Hi guys,
i bought a pair of biflex 420,put them in big BR enclosures.Dimensions: height 4.1 ft ,width 2.1 ft wide,depth1.8 in 6/7 inch MDF.No bracing,no dampening.I simply copied those speakers from a friend of mine and in his set up they sounded very good.
i have pretty good bass for a single driver system but the voices are a little bit nasal and the reproduction of complicated messages not very clean.i have tried different level of dampening without success.I am wandering wether it comes from box vibrations or from the metallic dust caps of the 420.i read that some people removed those dust caps to get rid of nasal and dirty sound but i am hesitating since i understand it is a non reversible step.Any advice on what to do?
Thanks.
Charles.

[Old Guy]

I suggest just putting a 4 inch felt cover on, it will damp the overtones from the aluminum. Can be razor bladed off later, but will leave glue residue...

[charly1944]

Thanks Old Guy,
For the felt,what thickness do you recommend?4 inches seem to go beyond the aluminium cap(3.1 inch diameter).Should it be that big or should it be a 3.1 inch diameter of felt?For the felt not to fall down are you suggesting to glue it( with removable glue?) on the whole surface of the cap or just on the hedges?Finally if i hear an improvement with the felt would you recommend to take the further step and replace the metallic caps by paper caps?
Thanks.Charles.

[VolvoHeretic]

What glue is removable? Wall paper adhesive? or maybe just flour and water? For a source of felt, try and find an already preformed round topped ladies hat like several my daughter possesses.

[Old Guy]

There are commercial felt caps no need to cut up hats. You want a bigger cap as you have to cover what is there.



Speaker Parts, Dust Caps, Gaskets, Lead Wire, My Audio Addiction

Google "speaker repair parts" to find suppliers. That guy has 3.75, MEASURE FIRST, I always used 4's. You want enough room to work without touching the aluminum.

BE CAREFUL SUBSTITUTING GLUES! A quality speaker glue is best. You might want to talk to a local reconer and get his advice.

[charly1944]

Thanks Old Guy,
Very useful source of caps.So, if i understand you correctly you dont recommend to get rid of the alu cap and replace it by a felt cap but rather to cover the alu cap by felt that should be glued on the internal edge of the medium/treeble of the 420 and not on the aluminium cap itself.I would have thought it had to adhere to the cap to dampen the overtones properly.For the glue,i will try to find a reconer and ask for his advice.i will keep you informed.
Charles.