Mellow Acoustics – FrontRo II Speakers

Our price: £9,500.00

Mellow Acoustics – FrontRo Speakers II – At HFL, we couldn’t be happier to present a new hybrid electrostatic speaker by FrontRo, designed and hand-built here in the UK. Having always admired the clear and detailed sound of electrostatic loudspeakers, Tim Mellow created a new design that was more efficient, compact, and attractive in the home than anything previously available. Also, nearly all loudspeakers he heard sounded nothing like music played live in the room because most real instruments don’t beam the sound towards you at specific frequencies. Hence, loudspeakers generally lack the room-filling effect of live music that immerses you in reflected sound to produce that lovely sense of space and airiness. Tim spent over five years designing and developing his own concept for a new type of hi-fi speaker, driven by his desire for a way of reproducing recorded music as if it were a live performance. A benefit of the improved quality of the reflected sound is that it is recognized by the ear as belonging to the direct sound so that the two are combined (Haas effect), which in turn enhances the stereo image. If you close your eyes, you can hear each musician’s location. If you are open to a different approach which is very captivating, please do come in for a demo and listen for yourself. We’re sure you’ll be impressed.

HiFi Pig Review –

FrontRo is a compact hybrid electrostatic loudspeaker that is designed and hand-built in England, using locally sourced materials and joinery, and embodies fresh design theory. After years of research and refinement, FrontRo uses the Oscillating sphere concept to radiate sound as uniformly as possible in all directions, like dropping a pebble in a pond. It immerses you in reflected sound as well as direct sound and thus creates a holographic sound image – unique amongst high-end speakers for the true audiophile.

The latest version features a new dynamic woofer with a powerful rare earth magnet for extended bass and an improved delay line for extra sparkle in the extreme treble.


Amplifier suggestion for FrontRo

We are often asked to recommend a partnering amplifier for the FrontRo. Our favourite amplifier currently on the market is the English Acoustics Stereo 41c which is based on the classic Leak Stereo 20, the first stereo amplifier to be introduced to Britain right at the birth of stereo LPs in 1958. Although the circuit topology remains completely true to the original, this new version has improved modern components, including the output transformers, modern safety features and better visual build quality, with a variety of colours available. The latter is not surprising considering that in 1958 amplifiers were generally hidden in bespoke cabinets along with the turntable, tuner and often the loudspeakers, whereas nowadays proud owners like to have their tubes out on show. As a result of the improvements, the English Acoustics version retains the sweetness and ambience of the original while packing more punch in the bass.



Nearly all loudspeakers currently use the age old ‘dynamic’ principle of a coil in a magnetic field pushing a cone or dome back and forth to produce sound. The moving parts are slow, heavy and very prone to producing unwanted vibrations of their own.

By contrast, with an electrostatic loudspeaker;

  • The diaphragm is driven by the same electrostatic forces that make your hair stand on end when you rub a balloon and hold it near your head.

  • The diaphragm is incredibly light and responsive (six times thinner than human hair) – it is the closest thing to moving air directly without any kind of mechanical structure.

  • The diaphragm produces no unwanted vibrations because it is damped by the grille cloth at low frequencies and the air load at high frequencies.

  • The mechanism is almost perfectly linear so the sound isn’t distorted.

  • There is no box to spoil the sound.


Oscillating Sphere concept

Unlike other electrostatic loudspeakers on the market, FrontRo uses an innovative concept to prevent the waves from beaming towards you: The Oscillating Sphere. Imagine a rigid sphere oscillating back and forth in free space, spreading the sound out in all directions across the entire musical spectrum. This is the perfect dipole sound source and has a smooth response.

To imitate this, using a flat diaphragm, the FrontRo electrodes are divided into concentric rings, which are fed from a delay line. Hence the sound radiates from the center first and then from each successive ring until it leaves the outermost ring, by which time the sound from the center is some distance from the diaphragm. Hence a hemispherical wavefront is produced, which spreads out like ripples in a pond. Unlike previous arrays, this one does not need losses in the delay line (or shading) to smooth its response, which increases its efficiency and thus enables a more compact design. To allow the sound out, the pattern of holes in each electrode is the same as that of the seeds on a sunflower head. It turns out that nature has found the most effective way of packing circles within a circle!


OS Diagram

Electrode Diagram


Technical specifications

Overall dimensions (without feet): 762 mm (H) x 494 mm (W) x 291 mm (D)
Recommended amplifier power rating: 25 to 100 W
Frequency response: 40 Hz to 20 kHz
Input impedance: nominal 8 ohms.
Sensitivity: 84 dB @ 1m for 2.83 VRMS.
Maximum output: 98dB SPL from electrostatic unit for 14 VRMS (input protected).
Crossover frequency: 500 Hz, 2nd-order
Mains connection: 240 V, 4 mA





David Price, StereoNET: It possesses all the desirable traits of a great electrostatic – a superb, near translucent midband, super quick transients and no nasty boomy box sounds ….. you get an excellent sense of spatiality; it’s a truly expansive sound and not one that beams out at you

David Price and Mike Evans, HiFi Riff: Watch their glowing review on YouTube here.

Janine Elliot, Hifi Pig: “The speakers produced a full and detailed sound. Turning to Saint Saens ‘Carnival of the Animals’, this has very spacious orchestration ably shown off by the FrontRo, the two pianos performing side by side centre stage…a highly 3D performance with pin-sharp top end and extended bass. The FrontRo was simply excellent in portraying the composer’s thoughts, working well at low level as well as loud. Birds and sea waves were equally real that my cat even pricked its ears to go hunting for game.”

Paul Messenger, Hi-Fi+: “The bass line was invariably crisp, clear and well defined….The vocal talents of Joplin were portrayed well on the FrontRo, suggesting a speaker of rare detail, vocal clarity and dynamic range…This is a loudspeaker with a distinct focus on sound that simply does the business, supplying good sound quality wherever one sits and outstanding quality if you listen in the sweet spot.“

Jess Marshall, Luxury Lifestyle Magazine: “(FrontRo) speakers are, an investment in music, an investment in entertainment, and an investment in interior design. For music lovers everywhere speakers don’t get much better, or more stylish than this.”

Jarone Ashkenazi, Upscale Living: “After five years of development paying meticulous detail to design and audio quality, FrontRo has positioned itself as possibly the world’s most luxurious electrostatic audio units.”