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Instruction Manual for:
FRm Loudspeaker Series
Contents
1 Introduction
2 Final inspection
3 Connections
4 Initial positioning
5 Set up guide
6 Getting the best from your speakers
7 Maintenance
8 Specifications
9 Guarantee
10 Packing instructions
1. Introduction
Thank you for buying a pair of FRm (Full
Range modified) loudspeakers.
These
loudspeakers are unique in that they are very
flexible in their use, especially the FRm 3 which
will give you several options of use. The bass
performance is adaptable to a range of different
situations.
Please read the “set up” guide when first using to
become familiar with the options available to
tailor their use to you particular system and room
acoustics.
Background to the FRm loudspeakers
If you stop and think about it Full range loudspeakers
have a great deal to offer compared to a conventional
2 or 3 way. Going back to basics the only reason a
loudspeaker has more than one unit is because one
has difficulty covering the whole audio spectrum from
which is normally thought of as 20Hz to 20,000 Hz.
However there is virtually no musical information
below 50 Hz and above 15 kHz. The reality is however
that the additional complexity of using more than one
speaker can cause problems in other ways which
although not as obvious as poor frequency response,
can make life difficult for the amplifier driving the
speaker, especially lower powered valve amplifiers.
For example a typical 2 way speaker uses a larger
speaker for bass and midrange with a small dedicated
“tweeter” to reproduce the treble part of the spectrum.
All well and good you might say but if we consider
exactly what happens the problems in doing this
become more apparent:
If we ask a loudspeaker to reproduce a rising
frequency there will become a point where the
crossover will limit the energy being supplied to the
bass unit and a crossover will start to send it to the
tweeter. At that point both speakers will try to
reproduce that note and therefore there will be
distortion and confusion to the ear as time delay and
phase shift start to add distortion to the way that
frequency is reproduced. The result is not a “bad”
sound but a loss of detail in the stereo image. The test
equipment used by a manufacturer will be looking for
harmonic distortion and a flat frequency response, so
if the speaker passes those tests it will be classed as
“good”. Now the reality is that we are not sending
