More Bass Please
A high-output, ultra-compact sub-bass is almost a contradiction in terms. Fashion and convenience have seen a number of
small, powered bass systems enter the market, joining the large number of plastic top-end boxes now available. Most of the
presently available boxes tend to go ‘thud’ rather than ‘doof’. Doof is good, by the way.
There are a number of technical reasons why it is hard to develop and project real low frequency bottom end from a petite
enclosure, but there are a small collection of notable exceptions. Most of these exceptions have minimum size and maximum
Another problem facing a designer of compact powered bass boxes is amplifier power. A small bass box needs a very powerful
amplifier and speaker combination to make up for the small air volume. This adds to weight and more cost. As a result, most
small systems that will fit in a car have either very limited low frequency response and output, or poor projection characteristics.
Most of them are half-OK bass boxes, but not a real sub-bass.
A Small Powered Sub-Bass with All the ‘Grunt’ of a (Real) Big One
The RCF 705AS is a 15” self-powered band-pass design, powered by an 800-watt class H high current amplifier. With
a maximum output of 130dB, the 705AS still measures 100dB at a distance of 32 meters; that’s pretty impressive from
a box that will fit in a small car.
To achieve that result, there’s a pretty clever fusion of technologies being applied.
It is a little known fact that RCF engineers back in the mid sixties developed and built the world’s first 300-watt
commercial amplifier. This is at a time when 100 watts was considered a monster, and solid-state amplification was still
in relative infancy. Most loudspeaker design and manufacturer was very ‘hit and miss’ and based on data that
was theoretical rather than established fact.
RCF was the first in Europe to have a fully equipped research centre for the study and analysis of loudspeaker and horn
physics and this effort established many of the practical conventions that are still applied today. The RCF contribution
to the world’s body of audio engineering knowledge should not be underestimated.
It is this broad and extensive intellectual pedigree that leads us to the RCF product base we have now. RCF is one of the
very few speaker box manufacturers that design and manufacturers the drivers for their boxes, researches amplifier technology,
and has also built products for most of the world’s concert audio speaker system manufacturers.
It naturally follows that RCF products reflect this background as is easily proved by asking anybody who has owned an RCF
speaker driver or speaker system. Even today the RCF Art series is the ‘darling’ of the rental industry and
is still considered the only ‘professional’ plastic powered system.
A workhorse or a show pony?
Looking at the back panel, it’s simple but has all the qualities a rental operator would like. Three switchable cross
over frequencies, stereo full range and filtered line level outputs, phase selection, rigging points and a detailed LED
status array begin a long features inventory. The intelligent limiter and protection is the icing on the cake and is only
sonically noticeable when the source mixer is a solid bar of red lights. ‘Punter proof’ is the name of the game;
even to the addition of a steel front grill cover to keep wayward glass objects from becoming rattle fodder at the end of
On the Back Panel They Thought of Everything
So, What’s The Verdict?
It’s not just a powered bass-box; it’s a bass solution. With 130dB output it is pretty impressive with the
lumps in all the right places. It has enough ‘grunt’ to keep up with the 15” & 2” high-powered
RCF box which is a tall order for a compact sub and the “clip light appreciation society” won’t damage