For applications where more than two pairs of speakers are required installers use “100v line” amplifiers (70v in America) which are specially designed to power many loudspeakers – for example in retail environments or train stations. 100v Line Signal To achieve distribution to many speakers daisy-chained over a long distance the 100v line amplifier outputs very strong “100 volt” signal. Loudspeakers for this type of amplifier need to be equipped with step-down transformers which convert this high-voltage signal to useable “speaker-level” signal. Normal Options Commonly loudspeaker manufacturers offer two versions of the same product: “low impedance” for use with normal amplifiers, & “100v line” with a 100v transformer built in for use in 100v line systems. Often the part number will end with a “t” to denote transformer. Normally the internal transformer cannot be bypassed if you need to want to use these loudspeakers with a low impedance amplifier. Vision Offers Flexibility Vision’s loudspeaker & amplifiers are all “low-impedance” because of the superior sound quality & greater power output. Instead of restricting installers to one or the other Vision offers the unique add-on SP-100V transformers which simply “retrofit” to any low impedance speakers. The SP-100V inserts between the 100v amplifier & the low impedance loudspeaker allowing any low-impedance loudspeakers need to be used with a 100v line amplifier.