It is well understood the importance of getting a well matched amplifier for your speakers, or vice versa; getting the proper speakers for your amplifier. Now you can make virtually any amp/speaker combination work well together with the ZEROs.
The ZEROs are the simplest type of transformer called an auto transformer or autoformer. They are used to multiply the impedance of any speaker so that it "feels" like the optimum load for the amplifier being used. They are very helpful in matching speakers to amplifiers. By adjusting the speaker's impedance, both the damping factor and the maximum power transfer of the amp/speaker can be tailored for best sound. Almost all amplifiers sound better when driving a higher impedance speaker, simply because amplifiers produce less distortion when driving less current.