902-8b bug screens

[Russellc]

How uptight! That "magnet can S_U_C_K in there"

Oh brother,
Russellc

[Todd W. White]

The 808's, 902T's, 908's, and some of the 902's had a loading cap on the rear of the diaphragm to increase power handling. It also decreased the upper harmonics - made them sound not as good.

Prior to having Pascalite diaphragms, I either used the Symbiotik ones or the aluminum ones WITH the loading caps in professional installations where I wasn't DEAD SURE the owner's wouldn't blow them up from abuse. The Symbiotik's sounded WAY BETTER than most everyone else's drivers anyway, so it was a fair trade-off. I have always removed it and installed a damping material behind the diaphragm when sound quality was paramount, and I knew the system wouldn't be abused.

Now that we have Pascalite diaphragms, I recommend removing the loading caps and installing the felt pad Altec used (or a hunk of fiberglas cut to fit) on the inside of the rear cover of ALL small-format Altec drivers, whether you use the Pascalite diaphragms or not.

[just me now]

Todd --
when you say All small format Altec drivers, you don't mean 802G,s; do you?

clarification please......

pretty please....

[Todd W. White]

Yes - I use the felt pad and the exposed diaphragm for ALL of the small Altec drivers now, regardless of diaphragm type (I no longer use Symbiotik diaphragms - only aluminium and Pascalite).

[dBu211]

Hi Todd,

You've got mail. Please reply...

Tks...

Khiew

[RonSSS]

As was mentioned, the bug screen is just glued to the gasket on the 902 series drivers. If you are carefull, you can remove it w/o destroying it.

I believe the drivers sound much better w/o it. Maybe not tremendously more extended, but it removes the "phasey" sound produced by the horns when you move your head around.

Try this if you can, play some pink noise and listen from the sweet spot. Move your head back and forth....maybe a foot or more. Or just walk around the room. You will hear the dips and peaks in the HF response. The screen acts as a diffuser, how can't it?
Remove the screens, and it largly goes away.

I have removed them from all my HF drivers, even my duplexes, and I like the improvement.

YMMV though......

BTW.....new gaskets can be made from thick cardboard, sissors and an exacto knife.

Ron

[Datubie]

Does this go for 604's as well?

Originally posted by Todd W. White:
The 808's, 902T's, 908's, and some of the 902's had a loading cap on the rear of the diaphragm to increase power handling. It also decreased the upper harmonics - made them sound not as good.

Prior to having Pascalite diaphragms, I either used the Symbiotik ones or the aluminum ones WITH the loading caps in professional installations where I wasn't DEAD SURE the owner's wouldn't blow them up from abuse. The Symbiotik's sounded WAY BETTER than most everyone else's drivers anyway, so it was a fair trade-off. I have always removed it and installed a damping material behind the diaphragm when sound quality was paramount, and I knew the system wouldn't be abused.

Now that we have Pascalite diaphragms, I recommend removing the loading caps and installing the felt pad Altec used (or a hunk of fiberglas cut to fit) on the inside of the rear cover of ALL small-format Altec drivers, whether you use the Pascalite diaphragms or not.

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[Todd W. White]

Yes, with the possible exception of the 604E. Jerry Hubbard says the "E" sounds better WITH the loading cap, and I tend to agree.

Can't remember if the "G" or the "H" had them, though...

[billfort]

The 604G has the loading cap and I feel it sounds better without it while using the felt cover lining Todd mentioned. Smoothed out the hot upper midrange a bit without hurting treble extension.

If hi-power SS is not your cuppa (I use low power tubes), this is a reversible mod definitely worth trying.

<font color="#FFFFFF" size="1">[ August 07, 2005 04:56 PM: Message edited by: Todd W. White ]</font>