Common Attributes
Each 8" driver has two cones, the larger covering from 2.5 kHz down, and the smaller one from 2.5kHz to 12 kHz. Above 12 kHz the highs are reproduced by the center of the driver, called the former. There is a mechanical crossover between these. The mechanical crossover is created by the paper fiber of the cones.
The 5" drivers have a similar design, but the crossover points are different.
Alnico Magnets
Alnico magnets were the original magnets used by Lowther. The stiff magnetic field of Alnico allows the driver to reproduce a great deal of the harmonic development of instruments and voices - information that makes them sound more real. This information can be described as extremely low level information, the "texture" of the sound. Lovers of vocals, orchestral, and other forms of rich music sound generally prefer Alnico drivers.
Neodymium Magnets
Neodymium magnets, or rare earth magnets, are used in the DX and EX series of drivers. Neodymium is extremely powerful for its weight. The sound of these drivers is extremely fast, with lightening transient response. They also have a big and bold flavor to them. People who listen to rock, jazz and other forms of "exciting" music tend to prefer these drivers.
Ceramic Magnets
Ceramic magnets have a fairly flexible magnet field. This means that these drivers have a softer sound to them, without the extreme detail of the other units. Best when the source material is imperfect. These have the same transparent sound and dynamic sound as the others, but with a little "soft focus" effect. Customers who listen to older recordings, or who just prefer a "back of the audience" soundstage, prefer these drivers.
Voice Coils
You can order 3 different materials for your voice coils. Aluminum is standard, and has the greatest speed and high end frequency extension. Silver can be ordered at extra cost, and presents a "cleaner" sound, with slightly reduced highs. Copper has a slightly warmer sound, and the extra weight will reduce the highs slightly.
You can order either 8 ohm or 15 ohm (and in some cases 4 ohm) drivers.
Hi-Ferric material is normally added to the voice coils. This increases transient response and damping.
I am often asked what I prefer, and why. So these are my own personal preferences, please ignore them when designing your perfect system, as my taste may not be the same as yours.
As a general statement, I prefer to hear the drivers as they were originally designed.
Alnico: 15 ohm, copper voice coil, non-Hi-Ferric. The exception to this is the PM6A, which I prefer with the silver voice coil, 15 ohm, non-Hi-Ferric for the slightly brighter sound it brings.
Neodymium: 8 ohm, standard voice coil with Hi-Ferric.
Ceramic: 8 ohm, standard voice coil with Hi-Ferric.