Specially spaced dual-coil magnetic pickup help soundwaves resonate.
The ACB Banjo Pickup System was developed by EMG founder Rob Turner and combines three technologies to accurately capture the unique tone of a banjo. The first is having a dual-coil pickup, which means the coils are spaced apart from each other to enhance frequency response. The second key is that the ACB is an active pickup with the preamp not only boosting the signal, but ensuring the pickup is noise-free.
As mentioned above, the coils are spaced apart, which allows "air gaps" to be built into the pickup. These air gaps allow soundwaves inside the banjo to resonate between the coil walls and produce an acoustic quality that has not been achieved in a magnetic pickup until now. Each ACB is supplied with "Air Plugs" that can be used to fill the gaps to control the amount of microphonics the pickup has. The third and final technology is the included thin strip (.002 thick) of shim steel. This strip of steel can be placed in a variety of places near one of the coils, between them, or directly over the top of either of the coils. The strip is another addition to the tone; it is not a necessary element to make the pickup work.