L200b

[sonofagun]

I remember one or two (?) customers who sent me the window screens to put new grilles on, so maybe seems these were OEM at least some time anyway.

The L100 always had the wood frames which I have the
design/construction specs for.

Minimum 1" thick foam is needed to effectively cut the L200 pattern into.

[sonofagun]

Originally posted by Mr. Widget
My only firsthand recollection of the foam grilles is from '79-'80. I remember being surprised at how thin the L200 foam was.

Many times when that early foam aged, it tended to thin in addition to crumbling depending on the environment it was exposed to.

[Mr. Widget]

Thinking back on it I believe the pair I was checking out were original early L200s. I have no idea if later L200s and L200Bs might have used the window screens. Seems really cheesy to me.

Hey Sonofagun, I do think your L100s quadrex grilles look fantastic, but I would be concerned about the absorptive properties of the foam for anything other than a decorative grille. Along those lines Joseph D'Appolito in his reviews of loudspeakers always measures the response with and without grilles. In every case the response is degraded with grilles in place so maybe it is only a matter of degree. I would intuitively think thinner foam is better than thicker foam.

As far as the thin foam being due to age the speakers were in perfect condition and less than 10 years old. I don't think the foam was degraded. (yet)

Widget

[sonofagun]

I have had acoustic testing of my foam done in the past with favorable results. Seemed that sonic transmission was little effected until thickness was well over 1".

I would be glad to send some samples to anyone here properly equipped to run tests and post the results here.

Some here have been using my grilles allready - perhaps they can comment on how or if sound was effected.

[gassy]

sonofagun,
Are you set up for business yet? I still want a set of grilles for the L100's I have.

[sonofagun]

Sorry - gonna be a month or so more.

[gassy]

OK, just checking in...

[mbottz]

I can verify that the window Screen frames are definately original. I sold stereo equipment in the 70's and got to set up the demo room as I was the manual labor for the shop. I clearly remember unboxing a set of new L-200's and hooking them up for the first time. They sounded incredible! I also rember upon taking the the grills off that I could not believe JBL would use a window screen frame to hold the foam grill for such an expensive speaker. But it sure did not keep them from selling.

MB