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In the Forum: Horn-Loaded Speakers
In the Thread: 60hz, GPA-515-8ghp horn...
Post Subject: Alnico vs. Ferrite vs. throat vs. whatever.Posted by Romy the Cat on: 7/1/2008

Klaus,

The 515-8GPH were in same scale as the 515G with slightly above 35Hz resonance frequency and 103 sensitivity -  a very good candidate for 60Hz horn. The 10” throat? No bolls to go for 9”, how about 8”?  I’m just kidding. The throat is that I always has issues with use 15” driver for horns – they kind of make people to go for larger throats but I would like to see 60Hz horn with smaller diver, let say 10” driver in 7”-8” throat. How, where to found a 10” driver that would have sound and characteristics of 515 drivers… Do not ask me… :-(

The S2’s diaphragm with clear plastic outer suspension is an original Vitavox cone that they did as a substitute for metal suspension in order to add a slightly more power handling for the S2 driver.

The Alnico vs. Ferrite on 515 driver? If you cross it at 500Hz and most likely with second order then I would say that there is no differences. Alnico is important to provide transients at mid and higher frequencies it would be less affective, if any at bass. Not to mention that it would make the bass channel more vulnerable to DC component demagnetizing. Alnico is better reacts to low level signal but it might be negligible in your case. If you do have a luxury to choose type of magnet in your 515 then I would go with a magnet that would depend from your amp. The basic rule is that I formulate for myself is following: SS PP amps must not driver Alnico and SETs must not driver ceramic frequency above 500Hz-1000Hz. If you use SS PP amp then a ceramic magnet is a must as Alnico would too much highlight imperfections of PP topology. With 500Hz crossover it become not so critical.

Rgs, Romy the Cat

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