Dr.-Ing. Peter Strassacker
Email: peter@lautsprechershop.de

Subwoofer Drive Systems

A good subwoofer driver consists of:
- a sturdy, rigid resonance free basket,
- a hard and rigid diaphragm with little resonance,
- a matching drive system (voice coil within the magnetic field).

But, what is a matching drive system?

A well matched drive system shouldn't be too strong or too weak. This is made clear by the following picture showing the Alcone AC 12 SW4 in a closed cabinet. The drive has been weakened by resistors. in geschlossener Box
You will notice that the flattest frequency response (same volume between 50 and 200 HZ) occurs when a dropping resistor of 6 to 8 Ohm is used.

The same flat frequency response can be achieved by using a weaker magnet.

Rules derived from this fact:

The following statements are general, they don't apply just to the AC12; this driver is, however, quite suitable to illustrate this aspect, since the AC12's drive system is quite strong and may, therefore, be weakened by using resistors or a weaker magnet.

The verdict

A matching drive system is needed; in a closed cabinet it should be relatively weak (as pictured above), in a bass reflex cabinet it should be somewhat stronger.

Bass driver page     Home