Compression driver material

[vita]

Hello,
Please,somebody would have an idea in which material(type) is made the pot of compression driver.
Thank you
Best Regards
Stefano

[Maron Horonzakz]

Witch compression driver?

[Steve Schell]

If you are speaking of the old alnico Altec and JBL designs, the external pot structures are made from low carbon steel or iron. Carbon is detrimental to magnetism, so the lower the carbon content the better.

Generally a well designed driver will have at least three or four times the cross section in the rest of the circuit as in the voice coil gap area. Ideally the pole tips will saturate while the rest of the circuit runs well below saturation. This also makes the material choice somewhat less critical for most of the circuit.

[vita]

Hello,
thank you for your answers. I have a tweeter alnico which makes 102db. I miss 1db for my installation. The simplest solution is to sell him and to buy a new pair. Other solution is to make a new pot and to add a supplementary magnet and i keep the same internal volume. The current magnet weighs 340 grams.Bad idea? I've read the good steel is 1002 or 1006 low carbon,but i am not a specialist.
Best regards
Stefano

[Steve Schell]

Do you mean that you have a pair of tweeters that vary in sensitivity by 1dB? To me this seems a good result considering the variations in most mass produced motor structures and voice coils. Perhaps you could buy one more pair of the drivers then select the best matched pair from among the four.

I have never tried adding more magnet to a motor, but this is what manufacturers sometimes do when they stack magnets. Seems this would be difficult to do in a completed speaker though.

1002 is very low carbon iron, probably used only for pole tips if at all. 1006 is also very good, though it has more carbon than 1002.

[vita]

Hello,
In fact, it's a fostex T500a and among all the tweeters that i have tested, it has a quite simply fantastic sound, but it misses 1 db.(i want 103db.or more).If i put a second magnet alnico 5dg of the same weight, it would have gained a little sensitivity,i think is possible.The low carbon 1002-1006, it's rather for the pole plates, but maybe that could go for the pot(I keep the same plate but new big pot).These experiment has a price for 1db, but if that function I will be satisfied.

Best Regards
Stefano