Does anyone know these ISOPHON horn drivers??

[zygibajt]

Hi,
I just got four ISOPHON horn drivers.
Two of them are tweeters named PANORAMA 2000 , 8ohm 800-15000Hz.They have extremely big ferrite (or neodymium) magnet and short aluminium horn (driver no. 2 or no. 3 from the picture).
The other two are midrange drivers with bigger (probably some kind of plastic ) horns.These have alnico magnets and no name on them (accept Isophon).These are number 1 from the picture.
Does anyone know this drivers??? are they any good.Sound quite good I think.Both of the midranges are like new ,perfect condition,and one of the tweeters is rabbing a bit at high levels (might be some dust in the voice coil).
With the drivers i got these funny ,look like heatsinks thing (also on the picture).It makes tweeters less directional when attached.
If you know anything about those please let me know.

Bartek

[Cybergent]

Where did you find that picture? Museum theft?

I experimented with those speakers in the end 70s to early 80s.

They are no good. Just crap.
Sound terrible. Just forget.

Maybe good as a siren.

[sreten]

The "heatsink" is an acoustic lens.

they appear to be PA drivers requiring dedicated
complicated crossover design / equalisation.

Not very good for general purpose or simple crossovers.

sreten.

[Cybergent]

The acustic lens sounds like a metal bell.
The tweeter horns are no good for PA, because they burn pretty fast.

And these horns are not linear at all. They have a squeeking sound.