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Monitor Audio RX8 loudspeaker review

Hi-Fi World - January 2010 issue




Noel Keywood finds Monitor Audio's new RX8 loudspeaker a thoroughly modern mover...


If you are looking for an affordable floorstander that delivers the goods in a very obvious way, then look no further. Monitor Audio’s new Silver RX8 costs just £1,000 – no fortune for a good hi-fi loudspeaker – and will bring a big smile to most faces. Yes, it even did to mine! This is a loudspeaker that hardly puts a foot wrong, and is more obvious in what it does than the floodlights at Wembley Stadium. But it’s also spot on engineering wise: a few Watts into the RX8 will have your cat straight out of the room!

Monitor Audio do a great job with finish and presentation so this weighty floorstander comes with a separate plinth to aid stability, adjustable floor spikes or polymer pads, and a single foam port bung. You can leave its shiny, dimpled alloy cones on display to intrigue onlookers or hide them behind a grill cloth for an altogether more discreet appearance. In this case the attractively veneered cabinets with smooth rounded edges will not jar the senses, because the standard of finish Monitor Audio achieve is about the best in the business, a nose ahead of both KEF and B&W methinks.
If you choose to leave the grille off then what confronts you is an intriguing array of hi-tech drive units entirely of Monitor Audio’s own manufacture.  At top is a one inch (25mm) gold dome C-CAM treble unit sitting behind a black protective mesh grille. Beneath it sits a large cone midrange unit, with chrome plated, bullet shaped dust cap at centre. Behind lies a sealed chamber.

Beneath this midrange unit are two similar drivers that handle bass duties, each loaded by its own rear reflex ported chamber. One vents through a front port close to the floor, the other through a rear port at top.

With stylishly angled descriptive legends and neat, gold plated bi-wire connecting terminals, at rear the RX8s look the part. They are conceptually positioned to be a thoroughly modern, high technology loudspeakers with a matching level of performance and in my view they achieve their promise.
But let us pause for a moment of reflection. 'Modern' surely means, ermm, obvious to the point of being brash, in your face and with inflated extremities to attract attention? Yep, the RX8s are a cock bird in season, with colourful plumage and a lot of noise to make. This is their milieu, and one they strut confidently, and with good reason. They are not all show and no go; there’s plenty of go to match their show. But their sound is very 'distinctive'...

Metal cone loudspeakers need a lot of running in and I am not quite sure what Monitor Audios really need, but we gave ours forty hours of heavy music and pink noise, as well as the company's own DeTox disc to get them well down the exponential run-in curve for metal cones. B&W say their loudspeakers need far less - fifteen hours will do - and most loudspeakers will loosen up to usability in five hours or so, ten hours being enough to say they are behaving representatively. After forty hours I think my views of the RX8s are fairly representative and Monitor Audio had already put some time on them, we were told later.

monitor_audio_rx8_rearI mention this because the RX8s have a conspicuously bright aura about them that dominates their character and running in softens the sound. These loudspeakers are not neutral by any means, but shinily metallic in their patina. It’s a nice light sort of zing that infuses their sound, but it is there all the same, as it has been with many previous Monitor Audio loudspeakers. To say they cast a bright light over music is to understate the case: they make it vivid. How a listener will react to this will be a matter of taste and expectation. I somehow feel that the RX8s are for younger listeners that want music thrown at them in high energy form, for this is what you get, but after spending time enjoying the LSO playing Tchaikovsky’s ‘March Slave’ I had to re-inspect my simple prejudices. The RX8s may seem modern to the point of being just a tad brash, but their bright light suits even conservative music forms. Being temporally tight with pin sharp timing, sudden orchestral interjections and changes of tempo were extremely well resolved, and their dynamic life gave an orchestra presence in the room. I found myself simply enjoying the sound, irrespective of its distinctive character.

However, a difficulty this character introduces is amplifier matching. Surprisingly, our resident Leema Pulse integrated really did not suit; the combo was too bright. A Naim Nait XS with its warmish balance might be an appropriate choice, and our resident Icon Audio MB845s valve power amps worked well. However, the underdamped bass of the RX8s responded well to the high damping factor of solid-state and I ended up using a Musical Fidelity AMS50 Class A power amplifier, that both gripped the bass cones tightly and was sufficiently neutral to avoid adding to the RX8’s candlepower.

It isn’t just their tonal colour that is so obvious. They are very sensitive and a few Watts will produce extraordinary dynamics. The RX8s are lightning-fast and dynamically strong, giving sudden orchestral fortissimo real bite; both the vigour and pace of an ‘allegro molto vivace’ movement within Tchaikovsky's Symphony No 6 was beautifully captured. So whilst the RX8s might be brightly lit and a tad brash, they nevertheless are able to capture the spirit of music and this is important in making them a fun listen, as well as a convincingly accurate one.

Stressed by the complex percussion work within Santana’s ‘Yaleo’, from the Supernatural CD, I became aware that whilst the presentation was both forward and explicit, the soundstage did not fall away backward as far as it can do, especially with a loudspeaker like the Eminent  Technology LFT-8bs also reviewed in this issue, for example. There was a slight edginess at times - the brashness I refer to earlier - and treble was ‘obvious’ shall I say, if not spiky or peaky. I noticed also that faced with complex music arrangements such as Yaleo, or much orchestral music, the midrange unit did develop a little colour - a slight haziness - and here I suspect its rear chamber and/or the damping within was making itself known, something I have encountered in the past when mounting a midrange unit in a chamber whilst prototyping World Audio Design loudspeakers (a common solution is to use an open back chamber). Sinking back to the simpler, slower ‘Put Your Lights On’ the RX8s came across as precision reproducers, thrusting Santana’s guitar out into the room, underscoring dynamic contrasts and imposing a sharply focused sense of timing that bolted down the track’s rhythmic progression. This gives the RX8s an eye-popping sense of life and vigour, a property they possess in abundance, and conspicuous strength.


"thoroughly modern, high technology loudspeakers with a matching level of performance; in my view they achieve their promise..."

Contributing strongly to their weighty, full blooded delivery is a bass performance that will please most people I believe. Like all Monitor Audio loudspeakers bass is strong and quality very good. My usual Angelique Kidjo torture tracks had the bass cones kicking but Musical Fidelity’s AMS50 amplifier remained in charge of the situation and drove the walking bass guitar line down the frequency scale with firm authority. The RX8s have more bass scale than B&Ws, although a little less control, Monitor Audio ensuring kick drum and bass guitar are always apparent in a performance. The RX8s go low too, although whilst they have strong deep bass they do not do subsonics. Like B&W, Monitor Audio tune their ports high (55Hz) in order to preserve bass speed and avoid room boom. I was occasionally aware of box ‘whoomph’ with heavy bass though, probably coming from the front port, a small colouration that passed unnoticed much of the time, but is obvious in our measurements. The single foam bung supplied would suppress this if used in the front port.


The tonal accuracy of the RX8s was apparent and welcome in their handling of vocals. The intrinsic sheen had some interesting effects, sending Renee Fleming’s highs spiralling upward it seemed, so intensely were they projected. I’m not quite sure it was all natural; the RX8s are strong in the upper midband and seemed to make her higher notes fly. But the overall effect wasn’t unpleasant and I noticed that generally the RX8s handled female vocals very well. Tmonitor-audio-rx8_detailoni Braxton was pinpoint sharp centre stage singing ‘Spanish Guitar’ from The Heat CD, and even her whispered Spanish phrases were spotlit. Guitar strings were cuttingly fast and the slow tempo still razor sharp in its timing. Moving down the musical scale a little, Mark Knopfler’s gruff vocals were equally well described centre stage, strong in dynamic contrast against a clean background. This made for a great intelligibility.

I marvelled at the speed of Arcadi Volodos as his fingers flew over the keyboard playing Shubert’s Sonata in E Major, the RX8s giving the instrument a fine sense of scale as well as luminous presence in our listening room.

The RX8 offers a larger than life performance from just a few Watts, a trick only a good floorstander can pull off. As affordable floorstanders go it has to be amongst the best in its price class, even though I have to say it is very distinctive in what it does and may just be a little too Wembley Stadium for listeners who like a gentle delivery. There’s no getting away from the fact that their razor sharp timing, basic accuracy and energetic bass will be the stuff of dreams for many and I can vouch that it’s one very enjoyable listen.

At the price this is one very accomplished, high energy floorstanding loudspeaker that infuses music with life. Whether you like Rock or Classical it's a fun listen that shouts "high fidelity", whilst at the same time staying carefully within the bounds of accuracy. That makes Monitor Audio's Silver RX8 a great loudspeaker at the price.



verdict five globes

Entertaining floorstander that brings light, pace and timing to all forms of music, making listening fun.
Superb at the price.

+44 (0)1268 740580

- light, bright presentation
- good bass
- superb finish

- zingy
- edgy at times
- lack subtlety



Frequency response of the Monitor Audio Silver RX8 is a lesson in accuracy, our analysis shows. Little attempt has been made to enhance or ‘voice’ the loudspeaker distinctively; the Silver RX8 is close to tonally neutral and should sound detailed without being brash or shouty like so many modern designs. A small amount of lift around 12kHz will ensure treble is clearly present, but not excessive. There is a small dip below 300Hz that is related to an internal cabinet mode, peaks in our port output analyses show and bass rises quite substantially around 80Hz, an underdamped response that will ensure the RX8 has lively bass. The ports peak at 55Hz, a high value, and with output from both 6dB up on forward output at 80Hz they contribute substantially to bass energy in the room. Absence of low bass means the RX8, much like B&W equivalents, swaps subsonics for bass speed. Bass distortion measured a low 3% at 40Hz and the ports were linear too, delivering 6% at 40Hz.

Sensitivity was very high, with 90dB sound pressure level produced from one nominal watt (2.8V). With impedance minima of 4 Ohms and an overall measured value of 5.3 Ohms this is a 4 Ohm loudspeaker but it’s largely a resistive load that will be easily driven by modern amplifier, returning little energy to them. Our 200mS spectral decay analysis shows the RX8 also enjoys very low levels of  colouration across midband and treble, close to electrostatics, although it is inevitably ‘hot’ in the bass.

The Silver RX8 is a very neat and directed piece of loudspeaker engineering. With plentiful bass, obvious but not accentuated treble and a clear, smooth midrange it should offer excellent clarity and accuracy with a sense of dynamic liveliness. NK

FREQUENCY RESPONSE (what it means)


Green - drive unit;  Red - front port; Yellow - rear port

IMPEDANCE (what it means)


DECAY SPECTRUM 200mS (what it means)


DECAY MAP 200mS (what it means)


DISTORTION (what it means)


BASS DISTORTION (what it means)




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