Linn’s Klimax Exakt 350: A Review By Martin Colloms, HIFICRITIC

In one of the most challenging reviews he’s ever undertaken, Martin Colloms tackles Linn’s new digital active loudspeaker system and it’s partnering streamer interface. Can it’s £50,000 total price be justified?

Linn has developed considerable enthusiasm for
a loss-free path for music recordings from what
it terms the source. Here the source is not the
music, nor is it the studio origination (about which
the consumer can do nothing). Rather, Linn defines
it as the point at which, until now, a theoretically
lossless, digital audio signal becomes analogue, which
is of course inevitable in order to experience sound.
Linn’s classic viewpoint has long been that the
music source available to the consumer must be
protected and optimised. Readers may well recall its
historical emphasis on the importance of optimising
vinyl replay quality, rather than later stages of preor
power amplification, Linn aiming to drive the
rest of the chain with the best possible analogue
source signal.
An analogue source signal suffers from well
known but normally also well controlled losses at
every stage of the path to the loudspeakers. Each
stage will contribute some degree of impairment,
due to cables and connectors, grounding issues,
some inherent noise, plus distortion and bandwidth
limiting defects that are inherent in analogue
stages, even though they can be rather small when
considered stage by stage.
When an analogue audio signal from a power
amplifier arrives at a loudspeaker, the usual passive
implementation then involves a high power filter
network (the crossover) prior to the drive units.
Configured to combine the acoustic outputs of the
drivers in proper order, significant quality losses occur.
Active Drive
Although they’re common enough in professional
circles, active domestic loudspeakers are quite rare.
They use power amplifiers for each loudspeaker drive
unit, and carry out the crossover filter function at
pre-amp electronics level. This approach can provide
great rewards in overall sound quality, especially in
respect of more realistic dynamics. Linn’s expertise
in active speakers goes right back to the three-way
Isobarik loudspeaker, introduced nearly 40 years
ago, which was available in both passive (DMS) and
active (PMS) versions. (I recall a most enjoyable
and impressive afternoon at Paul Messenger’s place,
listening to his Naim-powered active Isobarik
PMSs.) Since then, all Linn loudspeakers have been
specifically designed to allow them to be converted
to active operation.
Digital Active
More recently it has been possible to shorten the
analogue system signal path by converting from
digital at a later stage in a high quality DAC/preamp
(eg a digital streamer), which includes a master
volume control and sends its output via long cables
to now active analogue loudspeakers. However,
Linn’s increasing mastery of DSP (digital signal
processing) has set the stage for the company to
remove still more lossy analogue stages from the
audio signal path, hence the new Klimax Exakt DSM
streaming control unit. This drives digital audio
directly to the new ‘digital’ loudspeakers with a
high resolution feed in stereo (and eventually up to
eight channels, for home theatre installations), via
a custom made, very low jitter interface running on
Cat5 cable.
As in some studio and other previous designs,
the designers’ intention is to postpone the
conversion to analogue until the last possible
moment, and Linn describes this conversion point
as the source. This critical conversion is done at
the individual inputs of an array of linear Class
A/B power amplifiers, each connected directly to a
drive unit voice-coil. Linn explains that traditional
analogue losses through speaker or interconnect
cables and active or passive analogue crossover
components are therefore eliminated.
Digital input, digital crossover loudspeakers,
either for studio monitoring or for higher
performance home and stage audio systems have
been available elsewhere for some years, so what
is it that makes Linn’s implementation special?
The clock jitter figures for the interfaces are
extremely low (just a few picoseconds), for which
there is some correlation with sound quality, and
the audio channels benefit from tight locking
or synchronisation. I also see some value in the
ambitious backwards compatibility program for
this technology, which will allow some previously
purchased Linn loudspeakers to benefit from the
new digital expertise.