REVEL Performa F228Be

Loudspeakers

My heart sank when the editor rang to ask if I could stay home on Friday to take delivery of a pair of Revel speakers for review. ‘Are they floor-standers?’ I asked. ‘Yep’ was the stern reply. ‘What series?’ was my next question. ‘Performa F228Be’, he answered. It was not the answer I had not wanted to hear.

It’s not that I don’t love Revel speakers… I do… plus I am also a great fan of Kevin Voecks who’s still the man in charge at Revel, ably assisted by his right hand man (who’s actually Revel’s principal engineer) Mark Glazer… and no less a persona than Dr Sean Olive rounds out the design team… talk about heavy-hitters in the speaker design fraternity!

No, I really do love Revel speakers… it’s just that Revel’s top-line floor-standers are all so large, and so heavy, that carrying them down the long, too-steep, and too highly-polished slippery wooden staircase to my

listening room is always so difficult that I worry not only about my back, but the safety of the speakers.

The equipmenT

This time around I was in luck. A new courier, obviously out to impress, readily agreed to help me carry each carton down the stairs… or at least he did until he came in and saw the stairs. ‘Have you got a rug?’ he asked. As it happened, I did… and I learned something. He turned the rug over, then laid one carton down on its side on the rug and then, to my delight, slid the whole lot beautifully down the stairs! Then, at the bottom, I didn’t even have to lift the carton up, as it was already tilted half-way to vertical… I just had to tilt it away from the staircase and the carton was once again upright. Ditto for the second carton and we were done. Why had I never thought of this?

Do you think I am having you on about how big and heavy these speakers are? The specifications put them at 1.18 metres tall, 302mm wide and 335mm deep… and that’s just the cabinets. The sturdy dual-box packaging makes them even bigger. As for the weight, each one tips the scales at just over 37kg… and that’s again without the packaging. I found the dimensions a tad confusing, because they’re so similar to Revel’s F-208 (the specifications put the F228Be at just 50mm less deep than the F-208 but otherwise the dimensions are identical) that surely it would have made more economic sense to make the two cabinets the same size? I think, Kevin, that there’s something we need to talk about… ( Editor’s Note: We have been told unofficially that the cabinets are the same size, and the differences are due to typographical errors in the printed specifications, but we were unable to officially confirm this at the time of going to press.)

As you’d expect from the driver layout on the front baffle, the Revel F228Be is a true three-way design, except that the low frequencies are divided equally between two 203mm bass drivers, rather than being handled by a single driver. The beauty of all three-way designs is that the all-important midrange is being handled by just the one driver, so you’re not getting any Doppler

distortion going on, and there’s no crossover anywhere near the crucial vocal range. (The electrical crossover frequencies are specified at 260Hz and 2.1kHz). The beauty of using two bass drivers is that you split the load, so the power-handling is higher and the excursion is minimised, so distortion drops away. It’s not very cost-effective, mind you, because it costs more to manufacture two small drivers than a single large driver, but I guess at the price Revel is asking for the F228Be, that particular cost isn’t going to be an overly large portion of the overall price.

The two bass drivers used in the F228Be are, however, works of art in themselves. The cones are made from a material Revel calls ‘Deep Ceramic Composite’ (DCC) aluminium, while the frames are fully cast. Rated by Revel with an overall diameter of 203mm, the cone itself is only 158mm across, and the Thiele/Small diameter is 170mm, for an effective cone area (Sd) of 227cm². This means that if Revel had used a single bass driver, it would have had to have been around 270mm overall to deliver the same ‘punch’ as the two drivers on the F228Be. As for that DCC material, Mark Glazer, Revel’s Principal Engineer, says the cones are made using a plasma electrolytic oxidation process that uses a plasma discharge to create a ceramic coating on both sides of an aluminium core. The two ceramic layers provide constrained layer damping that pushes the cone’s breakup modes outside the pass band, allowing the driver to maintain ideal pistonic motion through its entire operating range.

To ensure proper voicing during the cross from the two bass drivers to the midrange driver, the midrange driver’s cone and chassis are made from exactly the same materials as the bass drivers. In fact the overall construction is identical… the midrange driver just has a smaller diameter cone, at 130mm. (Again, this is a nominal measurement. The cone itself is just 105mm across, and the Thiele/Small diameter is 112mm.) Obviously the most distinctive aspect of the cone material Revel is using is that it’s white… almost chalk-white, in fact, which is presumably the ‘raw’ colour of the ceramic material used.

I can’t say that I am a huge fan of this colour—and my wife certainly wasn’t!—but once you’ve attached the supplied grille, which is black cloth stretched over a fairly flimsy but perfectly adequate plastic frame, you’ll only be able to see the drivers under some lighting conditions. The surrounds of the bass drivers and midrange driver are made from Santoprene, which is a thermoplastic vulcanizate made from rubber particles encapsulated in polypropylene. Santoprene combines the longevity of rubber with the flexibility of foam without any of the drawbacks of either material and as a result is now one of the very best materials available from which to make loudspeaker surrounds.

As you’ve probably already guessed from the model name, the 25mm diameter dome of the F228Be’s tweeter is made from Beryllium (chemical symbol: Be). The magnet used to drive the beryllium dome is massive, comprised of two 85mm diameter ceramic magnets. Beryllium is becoming the go-to material of choice for tweeter domes, not least because it’s half the weight of either titanium or aluminium, yet four times as stiff, but also because it’s also more self-damped then either of these metals. (For the record, Beryllium is also a metal, albeit a ‘rare earth’ metal.)

The Beryllium dome not only makes it the odd driver out in terms of construction material, but also makes it the odd driver out in terms of colour, as it’s basically black. Revel has largely ameliorated this visual discontinuity by fronting the dome with a waveguide that’s made from exactly the same material used to make the cones on the midrange and bass drivers. According to Kevin Voecks, this waveguide ensures that the tweeter’s dispersion characteristics match that of the midrange transducer in the crossover region, and also ensures wider dispersion at higher frequencies. ‘ This gives the loudspeaker very smooth sound far off-axis,’ says Voecks, ‘ providing consistent sound over an exceptionally wide listening area, which is an important contributor to overall sound quality.’ I have to say that I’m not sure that calling it a ‘5th-generation acoustic lens waveguide’, as Revel does, is a great idea, partly because it seems incredible that in these days of finite element analysis it could take five generations to arrive at a design for a tweeter waveguide… but also partly because I cringe to think that at some time in the distant future the company could be offering a ‘457th-generation acoustic lens waveguide.’

As you can see from the photographs accompanying this review, the Revel F228Be is a bass-reflex design, with a single circular port located on the front baffle, immediately below the bottom-most bass driver. This port is 70mm in diameter for most of its length, flaring to 80mm at either end, and is 160mm in length. The inner and outer flares are done using plastic mouldings, with a short section of cardboard tubing linking the two. Unlike with some other models it offers, Revel does not supply foam plugs that can be used to block or otherwise alter the output of the ports, but I guess that if you’d like to experiment for yourself, foam is cheap…

Around the back of the Revel F228Be you’ll find four large, gold-plated speaker posts linked by large gold-plated buss-bars. Leave the buss-bars in place if you’re not bi-wiring or bi-amping, but remove the bars if you are.

Beryllium is becoming the go-to material of choice for tweeter domes, not only for its weight, but for its self-damping ability

The manufacturer’s plate near the terminals advises that although the Revel F228Be is ‘ Designed and Engineered by Revel’ and gives Harman’s address in Northridge, California, it also says ‘ Made in Indonesia’ (in four languages).

The Revel F228Be is available in four high-gloss finishes: Black, White, Walnut and Metallic Silver, but it appears that here in Australia, currently only the Black and Walnut versions are available ex-stock.

In Use and LIstenIng sessIons

Since Revel is a part of the Harman Specialty Audio Group that also includes JBL, Mark Levinson, AKG, Lexicon and Arcam (and a group that has been owned by Samsung since 2018) it has complete access to the test, measurement and listening facilities at Harman’s headquarters. This includes Harman’s famous ‘shuffle’ speaker comparator, which is a device that operates behind an acoustically transparent (but visually solid) curtain that actually physically moves pairs of speakers into exactly the same spot in the listening room within two seconds, so you are able to hear true A–B comparisons between different speakers. It’s an amazing piece of machinery and, to the best of my knowledge, it is the only one of its kind in the world. It was used when developing the F228Be. Dr Sean Olive, of Harman, used to have an excellent video of this machine in operation on his excellent personal blogspot ( www.tinyurl.com/AHF-HKLab) but last time I looked the video seemed to have been removed for some reason (though the viewing screen still remains). You can, however, read all about the device, and see pictures of it, at www.avhub.com.au/ Harman_Test_Lab

The Revel F228Be speakers are good with rock. No, strike that! They’re absolutely fabulous with rock! I have been waiting for five years for Irish pop crooner Hozier to release another album, so ‘Wasteland, Baby!’ has been on constant rotation chez Riggs ever since it was released. Indeed I think I played it so many times through the F228Be’s alone that they could probably play the album all by themselves… no signal source required! I can recommend this spectacular new Hozier release to everyone, because it has something for everyone—rock, folk, gospel, blues, R ‘n’ B, and all are spiced heavily with the inescapable flavour of golden pop. The standout track for me is Dinner and Diatribes, not least because I wish I’d thought of the name, but also I just love the blues guitar on it, and the drumming is fabulous as well—the kick-drum during the opening bars really had the air in my listening room pulsing with energy. Plus once the pace of D and D ramps up, Hozier introduces two of my favourite musical devices—hand claps (hello Africa!) and a choir (hello Beethoven!). Handclaps also feature on the fabulous Movement, a lovelorn lament of a song, while if you want your speakers to really pump, just listen to the soulful sound of Nina Cried Power, where he sings ‘ Joni cried power, Nina, Billie, Mavis cried power, and I could cry power’ (and indeed this track also features the fabulous Mavis Staples). This last has more hand-clapping, more choral work and some incredible Hammond organ. The clarity of the midrange from the Revel F228Be was demonstrated to perfection for me whenever I listened to the title track, with its delicate acoustic guitar and Hozier’s closemiked vocals, despite the inevitable sibilants.

The superb clarity of the Revel F228Be’s midrange—and its incredible ability to reveal even the tiniest musical details—was amply demonstrated by the sound of Hope Csutoros’s violin on David Bridie’s composition She’s Upped and Gone, from his album ‘The Wisdom Line’. The way her delicate fills come in is just magical. As for Bridie’s performance on this particular track, it sounds exactly as though he’s channelling Leonard Cohen… both lyrically and vocally. You can hear his voice recorded more naturally (in fact so totally naturally that it’s just as if he’s live in your listening room giving a private performance) on the more accessible track that is People Come and Go, which benefits tremendously from the performance on it by Helen Mountfort on cello. And just listen to the way you can hear the mallet-hit drums on Book of Revelation, plus the throaty sound of the flugelhorn. Unlike Hozier, you do have to be a fan of Bridie to ‘get’ his music… plus the subject-matter is all a bit on the sad side, and delivered so well that you’ll feel sad too whenever you listen to it. That said, you really do have to listen to The Wisdom Line’s title track though the Revel F228Bes. (It’s instrumental, so I can guarantee you won’t have to listen to another sad lyric.)

The pitch accuracy and depthy-sounding bass delivery of the Revel F228Be was demonstrated to me perfectly on Tim Rollinson’s latest album, ‘Old New Blues’. If you’re a fan of ‘cool’ jazz, you’ll love this, not least because he’s roped in Steve Elphick and Toby Hall for this, his fifth foray into the recording studio. The sound of Elphick’s bass is always true and the Revel F228Bes reveal the depth of his melodic inventiveness. A standout track on this album for me is Old New Borrowed Blues, a Rollinson original (one of seven

The Revel F228Be speakers are good with rock. No, strike that! They’re absolutely fabulous with rock!

on this album, the other seven are all jazz standards—albeit really only ‘standards’ if you have jazz credentials) where Rollinson’s distinctive guitar playing reminded me a bit of Steve Bryant’s, but from a listening point of view, it was the joy of hearing the octaves and fifths delivered pitch-perfect by the Revels, along with the crisp dynamism of the guitar sound. You’ll love the trio’s take on Blind Willie Nelson’s Dark was the Night, Cold was the Ground… coincidentally yet another song title I wish I’d thought of!

Could the Revel Performa F228Be speakers be improved? I was totally happy with their sound quality, but I would have really liked it if Revel had included on the F228Be the ‘Low Frequency Compensation’ switch from the F-208 that can be used to reduce the speakers’ bass response when they’re operated close to a boundary. OK, so my room is large enough that I didn’t have to have the speakers close to any boundary, but that may not be true for all potential buyers. I would also have liked it if Revel had included the ‘Tweeter Level’ control from the F-208 that allows you to adjust tweeter level over a 2dB range in five increments… not because I wasn’t happy with the high-frequency balance of the F228Bes, but because it would have helped in situations which required a less than ideal position for the speakers in the listening room. Maybe Revel figures that if you can afford a pair of F228Bes you’ll be putting them in a room that’s large enough that you won’t need to make any adjustments.

ConClusion

Since it seemed inevitable that readers will compare the almost-identically-sized and almost identical-looking F-208 with this new F228Be design I thought I should address the elephant in the room in my conclusion, which is that despite the similarities, and the fact that the two models have the same number of drivers, and those drivers are identically-sized, Revel says the two models share no component parts… that the F228Be is a completely new design that uses materials that were not available when the F-208 was designed almost six years ago.

But does this mean that Revel F228Be is a better speaker than the Revel F-208? The simple answer is that yes, I do think the Revel F228Be is a ‘better’ speaker than the Revel F-208. But I say that not because it is a newer speaker, and most certainly not because it’s a more expensive speaker, but because I think the Revel F228Be sounds a bit more natural across the midrange, images a tad more realistically, has somewhat superior bass, slightly more uniform directivity and a rather more extended high-frequency response. The only bad news is the asking price, which is nearly twice the recommended retail price of the Revel F-208.

But on the flip side, the good news is that if you can’t afford the Revel Performa F228Be, there’s always the Revel F-208. Sam Riggs

lABoRAToRy TEsT REPoRT

Newport Test Labs measured the overall frequency response of the Revel F228Be as being 30Hz to 22kHz ±3dB, which is an excellent result, even though it’s not quite the 27Hz to 44kHz –6dB that is claimed by Revel in its specifications.

Graph 1 shows the room response of the Revel F228Be, as measured by Newport Test Labs using pink noise as a test stimulus, where the graph shown is the averaged result of nine measurements made in a grid with the centre of the grid on-axis with the tweeter. As you can see for yourself, the response is very flat, so that between 80Hz and 8kHz the response is within ±1.25dB. The low-frequency response is 3dB down at 45Hz, but stays at this level down to 30Hz, so the –3dB point is essentially at 30Hz.

A detailed plot of the Revel F228Be’s high-frequency response is shown in Graph 2, with the detail enabled by Newport Test Lab’s use of a different measurement technique, one that is effectively the response the speaker would deliver in an anechoic chamber. It shows the response both with the loudspeaker grille in place, and without it, and you can see that the flatter, more-extended response is delivered without the grille being present (black trace), such that without the grille the high-frequency response is 3dB down at 23kHz, whereas with the grille fitted it rolls off a little sooner, to be 3dB down at 17kHz, though it stays 3dB down right out to 21kHz. You can see that both traces continue to roll off until 30kHz, after which they rise to the tweeter’s resonant peak at 37kHz… a peak that’s suitably well-damped. As the trace tracks up to this peak you can see a very tiny resonance at around 32kHz.

The low-frequency performance of the Revel F228Be is shown in Graph 3, with the lab this time using a nearfield measurement technique that simulates the result the speaker would deliver in an anechoic chamber. You can see that it’s the front-firing port that delivers most of the output at frequencies below 45Hz, as the low-frequency output of the twin bass drivers begins rolling off at 60Hz. The acoustic outputs of the bass and midrange drivers are both 6dB down at around 230Hz, a bit lower than the electrical crossover point of 260Hz. You can see the output of the midrange driver (blue trace) is exceptionally flat and extended indeed. Remember when looking at this graph that you’re looking at ‘raw’ SPL levels— the lab has not post-processed the data to adjust for the differences in the diameters of the sound sources.

The impedance modulus of the Revel F228Be suggests that it should nominally be rated as being a 4Ω system, and indeed it should be rated as such according to IEC 60268-5 (16.1). You can see that not only does the impedance remain below 8Ω from 20Hz right out to 800Hz, but it also drops to around 3.4Ω between 80Hz and 100Hz, and to 3.5Ω at around 280Hz. There’s also a bit of a challenge for amplifiers just below 400Hz, where the impedance is just 5Ω and the phase angle (light blue trace) is around +40°… a pretty challenging load. Revel should either not be specifying the Revel F228Be with a nominal impedance of 8Ω or specifying

this, but adding a qualifier that its minimum impedance is 3.4Ω at 90Hz. As it stands, under European IEC regulations, the Revel F228Be is a very definitely a 4Ω system.

Newport Test Labs’ measurement of the Revel F228Be’s sensitivity came in rather lower than Revel’s specification of 90dBSPL, with the lab measuring 88dBSPL using its standard technique. This is almost to be expected, as Newport Test Labs’ technique is very stringent, and doesn’t do any speakers under test any favours, but large floor-standers mostly do quite well, so the 2dB disparity is a little surprising. However, despite this result, the 88dBSPL sensitivity means that the Revel F228Be is actually more efficient than the average high-quality floor-standing speaker (that average being 87dBSPL).

Graph 6 is a composite graph that shows the various different measurements made by Newport Test Labs on the one graph, so you can see the overall integration. (Note that the black trace stops at 20Hz simply because no data was measured below 20Hz for this particular trace.) The traces for the bass drivers and the reflex port suggest that the measured low-frequency response of the Revel F228Be could have been improved had the lab positioned the speaker under test closer to a room boundary.

Newport Test Labs measured the Revel F228Be as having a superbly flat and extended frequency response and above-average efficiency. Its overall low impedance and one difficult phase angle are something of an Achilles’ Heel, meaning that it will be a tougher load for the amplifier driving it than it might otherwise have been, but I would expect anyone who buys a pair of Revel F228Bes would also own a well-designed amplifier capable of delivering three-figure power output into a 4Ω load. Overall, the F228Be is a great example of superior speaker engineering… but I really wouldn’t have expected anything less from Revel. Steve Holding