The A-25 XL2 has an 8 ohm nominal impedance and is a very easy electrical load on the driving amplifier.  The unique “aperiodic” enclosure design affords marked control of the wide impedance variations common in all dynamic speakers near their resonant frequency. This, along with the optimized crossover which utilizes baked air core copper coils, metalized polypropylene capacitors and non-inductive resistors, results in smoother response and more efficient power transfer characteristics as well since the amplifier is working into a more nearly resistive—and more linear--- load.

The aperiodic design utilizes a highly damped vent (not a bass reflex port) whose acoustical resistance is very precisely controlled. This lowers the “Q” of the system through a high friction venting action. The listening result of the aperiodic design is better control of the bass and improved transient response producing noticeably better defined bass with none of the typical “boom” that is quite common to ported speakers.

Cabinet resonances are known to be a significant cause of coloration in speaker systems. Extensive bracing of a typical MDF enclosure can help reduce these resonances but at the cost of increased energy storage which is detrimental to bass performance. Speakers constructed according to these principles can often sound like the life has been sucked out of the music.  The enclosure itself is CNC fabricated from 13 layer Baltic Birch plywood with and additional veneer of American Maple on each side for a total of 15 ply and 20mm of thickness. This is both stiffer and lighter than an MDF loudspeaker enclosure of the same size. In addition, the enclosure is braced and cabinet wall vibrations are critically damped through the application of a constrained-layer material on all inside walls.