“The horn projects ethereally and is excellent, but please pay attention to the bass performance with the power and impact that until now I have only heard in an actual performance hall.
You will experience low-range frequencies that you have never imagined.”

Monthly Audio 2019.4

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The design brief for the Plotinus was to create the ultimate horn speaker that unlike its predecessor the Reference would fit into most people’s music rooms. Envisaged and planned for many years by Seawave Acoustic’s founder Bo San, the Plotinus finally came to fruition after the development of some key technologies to create what we believe to be the world’s first modern true horn loudspeaker.

Incorporating the openness, beauty and power of compression horn technology and coupled with ground-breaking bass performance and neutrality, the Plotinus is a loudspeaker that has earned its place in the highest echelons of the audio world.


Wood Horn

While a horn may share its appearance with a simple cone shape, it is actually the product

of some sophisticated geometry. At Seawave Acoustic we create our horns to match precisely

the compression drivers within them. Derived from complex mathematical equations, each true exponential horn is designed for a specific speaker and must be fashioned with great precision. 

To obtain the purest possible output, we employ the very finest wood. And it is only when witnessing the meticulous lamination of 20 sheets of 20mm white birch that one fully understands the care and craftsmanship that goes into this core component. 

It is painstakingly finished and painted by a highly-trained specialist in colours befitting an artist’s palette. Once fitted, the speaker comes into its own, bringing a lifetime of pleasure to eye and ear. 

Compression Drivers

Unlike most modern horn designs, Seawave Acoustic has retained the principle of the compression driver as immortalised by pioneers like Western Electric. Precisely created to meet the strictest

of design briefs, our components work perfectly together to create tremendous dynamic contrast, low noise floor and low distortion at even the highest sound pressure levels.

An example is the tweeter we produced especially for the Plotinus, which is made from a traditional Korean ‘Hanji’ paper, renowned for its strength and lightness. The new tweeter makes its debut appearance in the Plotinus, transmitting high frequencies naturally and eliminating any harshness. 

Uni-Mould Bass Enclosure

The enclosure of Plotinus is made from a Uni-Cast AC4C aluminium chassis which requires no assembly and has no joined seams. Unicasting is a difficult and costly manufacturing process. However, it delivers substantial benefits in resonance control and is ideal for the realisation of the reference design goals of the Plotinus. Once finished through a detailed CNC machining process the enclosure of the Plotinus is no less than a work of art.

We used an aluminium subframe further to strengthen the structure of the enclosure and to eliminate resonance. Moreover, a rubber anti-vibration material was applied three times to
the inside surface of the enclosure to suppress any remaining, extraneous internal resonance.

Not even the smallest detail has been overlooked in creating the ideal enclosure for the bass frequencies of the Plotinus – which is why its performance has to be experienced to be believed.

Non-Soldering Technology (NST)

Every electrical connection point in the Plotinus uses our proprietary non-solder methodology (NST). Because solder is lead-based, it impedes electrical signals and causes a drop in the voltage that negatively affects the sound. So instead, we twist and press together the connections, then seal them to create long lasting and higher performance electrical pathways. This results in an increased transparency of the loudspeaker and a heightened dynamic expression. Harmonic integrity is improved, too.

The Seawave Acoustic NST is a fine example of the lengths we go to, to minimise performance losses
in the original electrical signal as it passes through the loudspeaker.

New Classes of Component

The performance goals for the Plotinus required us to push the boundaries of every component of the loudspeaker. To realise the full potential of the new, unicast enclosure for the bass frequencies, we developed a new inductor. Utilising 11-gauge foil and 6N high purity copper, we managed to reduce its length substantially and lower the internal resistance to 1/10th that of the best inductors on the market. The result is an incredible speed and extension of the bass frequencies, almost as if no inductor were used at all.

World firsts

  • First real wood laminated horn with tailormade compression driver
  • First one piece moulded aluminium woofer enclosure
  • First Korean traditional Hanji paper compression driver membrane
  • First low-resistance inductor invented and developed by Seawave Acoustic

The resulting world ‘firsts’ have helped us fulfil our design brief of creating the world’s first true modern reference horn loudspeaker, which we hope you will soon have the pleasure of experiencing for yourself.


DesignTrue rounded horn type speaker, 4 Way 5 Speakers
Driver units Super Tweeter: Beryllium
Tweeter: Hanji Membrane, 25mm Conical wood horn 180mm
Midrange: Titanium 65mm Conical wood horn 480mm
Woofer : 2 x 200mm Hexacone
Frequency response30Hz – 50000kHz (±1dB)
Sensitivity93 dB/W/m
Amplifier requirements15 ~ 250 W
Weight150 kg
Dimensions (WHD)410 x 1605 x 789 mm
ColoursGold & Rose Gold / Red & Black / Blue (Poseidon Blue & Marine)
PriceUSD 130,000
Seawave Acoustic Mark
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Seawave Acoustic
#1108, 70, Gasan Digital 1-Ro,
Seoul, 08590,
Republic of Korea

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