User Guide

To get the best from your loudspeakers, it’s important to make sure the amplier
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 quantied 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 times 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 transient
peaks in the audio signal at 114dB(SPL(@1m)) when connected to an amplier
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
amplier capable of delivering the full 800W of its peak power handling.
In the case of Cuboid 3TX and 5TX, the inclusion of a 70V/100V transformer
determines the amount of power being delivered to the loudspeaker – see
previous page. The amplier ‘sees’ the transformer and not the actual
loudspeaker, enabling many loudspeakers to be connected together up to a value
that does not exceed the amplier’s power output capability in Watts.
What this all means is that for the best performance from your loudspeaker,
make sure you have an amplier 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 amplier will deliver 115dB(SPL) from a Cuboid 8 and nothing more,
but a more powerful amplier will have the headroom to deliver short musical
transients at higher levels, thereby ensuring that faithful reproduction of the
program material is maintained.
Product specications for each model are on page 21 of this guide.
Matching speakers and amplifiers
19/23
Cuboid
Loudspeakers
Loudspeakers
USER GUIDE
© 2022. Optimal Audio Group Ltd. (v2.2)
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