Somebody needs these....

[Roscoe Primrose]

Seen on ebay: http://www.ebay.com/itm/Electro-Voice-U ... Sw03lY58Zx

Wondering why the back of the cone is white? It's made of Styrofoam!

Roscoe

[DaveR]

This is one thing I clearly don't need to own. So there's one.

[Cogito]

why are the magnets so small?

[Roscoe Primrose]

Alnico. And, remember the scale, that's a 30" woofer...

Roscoe

[Pelliott321]

Me thinks he was making a joke

[SoundMods]

I recall many years ago a shop named The House of Sound had a pair of Electrovoice Patricians on display that was fitted with those 30-inch woofers. Let's just say that the Patricians did not break a sweat from pipe organ left-pedal work. My pockets were not nearly deep enough to buy them.

[tomp]

Actually, Alnico has the lowest strength of any of the magnetic materials. Here is a comparison chart. Old drivers generally had very limited excursion and the designers built them with a very small gap height. This concentrated the flux into a small area so the flux density was high. However the excursion was therefore limited. Any of the modern subs in the 15 to 18 inch range with Xmax figures in the 19 to 24 mm range have lots more linear volume displacement than the EV 30. The EV was way more impressive though.

Tom

Attachments

[tomp]

More on Alnico vs ceramic from the Altec Heritage site.

Tom

Attachments

[Jay Bala]

But ALNICO V sounds better.

[SoundMods]

I read a vintage white paper that discussed the ALNICO vs. ceramic magnet assemblies issue regarding sound quality. To make a long story short -- the ALNICO magnets completes the magnetic circuit around the voice coil -- the ceramic does not. Why does that matter? It provides damping and puts the "brakes" on the motion somewhat like how the pedals on a piano are used. The speaker follows the signal better and the rise and settling times are more in line with the actual signal.