To get the best from your loudspeakers, it's important to make sure the amplifier you are using is up to the job. Several factors have to be considered, and it's worth clarifying what they mean and how they affect the performance of a loudspeaker.
Loudspeakers tend to be quantified using Watts, but this is purely a measure of the amount of power a loudspeaker can take at its input over time, and not necessarily a measurement of how loud it might go.
Optimal Audio loudspeaker power handling is therefore quoted as Watts (AES) and Watts (Peak); Peak delivering 6dB(SPL) acoustic output higher than AES (AES2-2012 standard) and referring to the loudest transients a loudspeaker can handle without distortion.
In Watts, this means that the peak power handling of a Cuboid 3 for example is 120W, four time its continuous power handling of 30W. The peak power handling for a Cuboid 8 is 800W, four times its 200W continuous power handling capability.
So, give a Cuboid 3 30W of continuous power and you will get 98dB(SPL) out of it if you are standing 1m away from it. It will however be able to deliver renascent peaks in the audio signal at 114dB(SPL(@1m)) when connected to an amplifier capable of delivering the full 120W of its peak power handling.
Deliver 200W of continuous power to Cuboid 8 and you will get 115dB(SPL) out of it if you are standing 1m away from it. It will however be able to deliver transient peaks in the audio signal at 121dB(SPL(@1m)) when connected to an amplifier capable of delivering the full 800W of its peak power handling.
In the case of Cuboid 3TX, 5TX and 6TX, the inclusion of a 70V/100V transformer determined the amount of power being delivered to the loudspeaker (see - Cuboid - Transformer Taps). The amplifier 'sees' the transformer and not the actual loudspeaker, enabling many loudspeakers to be connected together up to a value that does not exceed the amplifiers power output capability in Watts.
What this all means is that for the best performance from your loudspeaker, make sure you have an amplifier that is capable of delivering more than a loudspeaker's rated AES power handling ability at the nominal impedance of the loudspeaker - 8 Ohms in the case of all low impedance Cuboid speakers. A 200W amplifier will deliver 115dB(SPL) from a Cuboid 8 and nothing more, but a more powerful amplifier will have the headroom to deliver short musical transients at high levels, thereby ensuring that faithful reproduction of the program material is maintained.
Product specifications of each Cuboid model can be found below
Cuboid 3 & Cuboid 3TX Specifications
Cuboid 5 & Cuboid 5TX Specifications
Cuboid 6 & Cuboid 6TX Specifications
Cuboid 8, 10, 12 & 15 Specifications