O N T E S T

Acoustic Energy Radiance Three

Loudspeakers

ake a good look at the tweeter in Acoustic Energy’s new Radi- ance Three, because it’s Acoustic Energy’s new ‘secret weapon’. Yes, TI know it looks a lot like a 38mm Peerless XT ring radiator, but apparently, according to designer Mike Thomas, the trick is the surround in which it’s mounted. He says the combination of the two technologies leads to the tweeter’s dispersion matching that of the midrange and bass drivers, which ‘dramati- cally naturalises the soundfield.’ Like all new technologies, it needed a catchy acronym, but the best Acoustic Energy could come up with was ‘DXT Lens.’

The Equipment As you can see from the photograph, the Acoustic Energy Radiance Three is a floor- standing four-driver model. What you can’t eter when it comes to cone drivers is their have smoother frequency responses which are see are the ‘outrigger’ feet at the base of Thiele-Small diameter (Sd) which I measured more extended at the high end. The build of the speakers that are absolutely essential to as being 133mm. This gives a cone area of the midrange driver is similar to that used for ensure these moderately-tall loudspeakers 138cm². The importance of this measurement the bass drivers, with a pressed alloy cone and are stable when they’re sitting on the floor is that it allows you to work out how big the a rubber roll surround that operates from a in your room, particularly if your room is bass driver would be if AE were to replace cast alloy chassis. The large magnet is centre- carpeted. (Our photographer forgot to attach both smaller bass drivers with a single driver. vented though its rear, to which a second them for the photo shoot.) The four drivers The answer is that that driver would have an flux-cancelling magnet is attached. The driver, are driven by a true ‘three-way’ crossover net- Sd of 276cm², so its overall diameter would which carries Acoustic Energy branding, is work, with the two 160mm alloy-coned bass be in the order of 240mm. That’s very good truly beautifully made. drivers working in parallel to deliver the bass. considering the small footprint of this design! In the introduction, I said that the Radi- I got those bass driver specifications from The bass driver has a pressed alloy chassis and ance Three’s tweeter ‘looks a lot like a 38mm Acoustic Energy’s website, but when I ran the voice-coil is punched for cooling, plus Peerless XT ring radiator’ because it does. The a tape measure over the speakers supplied there’s under-spider cooling as well. technical description of the tweeter supplied for review, the overall diameter of the bass The size of the midrange driver is also by Acoustic Energy also seems to match the drivers turned out to be considerably larger at odds with the specification. I measured description for the Danish manufacturer’s than claimed. I measured 180mm. Even the it at 150mm overall, with a mounting hole trademark tweeter, right down to the twin- mounting hole diameter—which is usually diameter of 139mm, whereas AE states it as wound aluminium voice coils, but when I used by manufacturers to identify diam- being 130mm. In this case, however, AE is removed said tweeter from the AE enclosure eter—was greater than claimed, at 170mm. erring on the glossy side, because all other to check for identification markings, there was However the only really important diam- things being equal, smaller midrange drivers no Peerless sticker attached, so I am no wiser.

20 Australian Acoustic Energy Radiance Three Loudspeakers O N T E S T

However, removing the tweeter did reveal mously thick Figure-8 wiring to each of the a little surprised by how small they seemed a ‘bumped’ backplate and double-stacked drivers. Very odd! The point at which the to be, and kind of immediately assumed that external magnets, as well as the fact that cable ‘loom’ went though the dividing baffle they might not be up to the task of delivering the tweeter’s terminals are soldered to the was not sealed. The cabinet is divided into high volume levels—and deep bass—in such internal wiring loom rather than connected ‘bass’ and ‘midrange’ chambers, with the a large room. Indeed I’d already started won- by cheap ‘n nasty slide-on tag terminals, so bass chamber being vented to the rear of the dering if I shouldn’t have set them up in my the exploration wasn’t entirely unfruitful. If cabinet via two 100×45mm ports, and the home office instead, even though it doesn’t you take a close look at the ‘horn’ in which midrange chamber via a single 50×30mm really lend itself to use with floor-standers the tweeter is mounted, you’ll see it’s not a port. The ports in the lower chamber had (though I always use it when auditioning simple shape, or even a curve, but a complex radiused entry and exit points, but the port bookshelf-style speakers). shape with three different ‘slopes’ at different in the upper chamber was simply cut to the As you’ve gathered, the bass output of radiuses. correct length (with the resulting swarf still the Radiance Threes made a nonsense of my As you’d expect of a four driver three-way attached). visual assessment of them! For such physi- design, the crossover is substantial, with The terminal block on the rear of the cally small speakers—and such small bass Acoustic Energy Radiance Three is set up with drivers, even with the undeniable benefit of twin pairs of terminals connected via gold- metal cones—the bass extends remarkably plated buss-bars that can be removed for bi- low, and it has an authority that it is impres- the bass wiring/bi-amping. At the bottom of the cabi- sive. Positioning will play a significant part net is a threaded hole that gives access to a in performance—because of those rear-firing extends separate chamber that can be filled with sand ports—but I found that so long as you keep (or lead shot) to improve stability (by lower- the ports fairly close to a rear wall, the bass remarkably ing the centre of gravity) and also to ‘anchor’ will always be highly satisfying. the design to ensure maximum bass perform- low, and it has ance. If you’re trying to work out what the RadianceThrees will look like in your living Acoustic Energy an authority room, they stand 920mm high, are 230mm Radiance Three Loudspeakers wide (at their widest point) and are 297mm that it is deep. I emphasise ‘widest’ point because, as Brand: Acoustic Energy you can see from the photographs, the sides Model: Radiance Three impressive. of the Radiance Three cabinet are curved. Category: Floorstanding Loudspeakers Each speaker weighs 18kg. RRP: $3,999 Warranty: Five Years three inductors (two air-cored and one lami- In Use and Distributor: Radiance AudioVisual nate-cored, all of which are cross-mounted Listening Sessions Address: Unit 33, 5 Gladstone Street so there can be no magnetic interaction I have to confess at the outset that I was Castle Hill, NSW 2154 between them), and six capacitors, includ- initially astounded by how much deep bass (02) 9659 1117 (02) 9659 1116 ing two electrolytics made specifically for energy was delivered by the Acoustic Energy [email protected] Acoustic Energy (they carry AE branding). Radiance Threes in my listening room. My www.radianceav.com.au Curiously, AE runs pairs of quite thin Figure-8 room is fairly large, quite starkly furnished, wire all the way up from the rear terminal has high ceilings and so when, after I’d set • Strong bass block to the crossover PCB (mounted behind up the Radiance Threes I then moved back the midrange driver), but then runs enor- to take a look at what they looked like, I was • Highly dynamic • Attractive cabinet

• Outrigger feet • Hard sound if overdriven Take a close look at the ‘horn’ in which the tweeter is mounted, you’ll see it’s not a LAB REPORT simple shape, or Readers interested in a full technical even a curve, but appraisal of the performance of the a complex shape Acoustic Energy Radiance Three Loud- with three different speakers should continue on and read ‘slopes’ at different radiuses. the LABORATORY REPORT published on page 64. Readers should note that the results mentioned in the report, tabulated in performance charts and/or displayed using graphs and/or photographs should be con- strued as applying only to the specific sample tested.

Lab Report on page 64

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I’d been listening to Cloud Control’s new in the evocative song The Seabirds (a Triffids album, ‘Bliss Release’, prior to the arrival classic). Since I’m mentioning the midrange of the Radiance Threes, and found when I I have to say that the mids delivered from listened to it using the AEs that the way they Emma Sidney’s new album, ‘Bossa Eyes’ had deliver the fast-paced bass lines that embel- a smooth, warm and very velvety feel that lish My Fear #2 was impressive, particularly was nigh on indescribable. Released on Move notes from the E-string. The understated kick (MD 3335) this CD has Sidney singing a drum sound is also magnificently delivered variety of songs that she describes as ‘a fusion by the Radiance Threes. The ‘raw’ sound of of acoustic Latin rhythms and laid-back jazz this home-recorded album is refreshing, but improvisations’, but that I’d just describe be warned that CC is also prone to injecting as being ‘cool as.’ She mixes such classics as plenty of FX and also occasionally overloads Antonio Carlos Jobim’s Corcovado with Kate one or more of the devices in its record- Bush’s Man with the Child in his Eyes to Cole ing chain. However, when they get it right, Porter’s I Concentrate on You and even throws which is more often than not on Bliss Re- in one of her own (Catching the Wave). Todd lease, it’s a great listen, and most particularly Sidney’s piano sound is also highly revealing when Heidi Lenffer is kicking out with that of the Radiance Three’s nuances. extraordinary voice of hers! Spinning up the hot-off-the-press ‘Bright The clarity of the bass was also high- Victory’, from Cabins, revealed that the up- lighted on The Triffids trackRed Pony, with per mids could be a bit in-your-face, but then Martyn P. Casey absolutely wringing the neck this is a very sharply-recorded CD, with not off his bass. He and drummer Alsy McDonald a lot of aural warmth, and so the Radiance also duet on the intro to Kathy Knows, but Threes were being goaded into it! It certainly this track is also notable for the clarity of meant that there was more than the average McComb’s vocal (at least when it’s not laden amount of ‘air’ around the extreme highs, down with echo, as in the choruses) which and also far better-than-average detailing in highlights the Radiance Threes’ credentials the upper treble. over the midrange. You can also hear this in I found the Radiance Threes to be highly AD the sound of ‘Evil’ Graham Lee’s pedal steel dynamic—it was easy to hear they’re efficient

as well—but I also found that in my large room I needed to be careful not to overdrive them, because whenever I did they immedi- 23 ately told me to ‘wind down the volume’ by sounding rather forced and hard. However, this very efficiency and dynamism actually predisposes them to deliver their best per- formance at low-to-average volume levels… and this, after all, is exactly what most loud- speakers spend most of their time doing! Try as I might, I could not hear any particular sonic characteristic that I could definitively attribute directly to the presence of that so-called ‘DXT Lens’, but the stereo imaging of the Radiance Threes is superb, and there’s certainly a wider-than-normal sweet spot, not to mention rather more sound-stag- ing depth than I might have expected, so if the DXT Lens was even a minor contributor to any or all of these admirable traits, it’s a definite plus in the design sense.

Conclusion This is an impressive new design from Acous- tic Energy, one that punches well above its weight in the bass. Position the AE Radiance Threes properly in any average-sized room, partner them with good-quality amplification and they’ll return the favours by delivering performances that will keep you coming back for more! Andrew Haddon

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SEE REVIEW ON PAGE 20 that also appears at its corresponding bass ing range, and where it dips below at 40Hz Test Results reflex port, while both the upper and lower and 125Hz, the infractions are only minor. As you can see from Graph 1, the frequency ports in the lower chamber of the Radiance However, going by the strict ruling of IEC dic- response of the Acoustic Energy Radiance Three exhibit resonances at 950Hz. However tate 268-5, which is the legal mechanism that Three was extended—both in the bass and the level is very low compared to the primary covers this specification, the nominal imped- the treble—and also highly linear, with the forward output, and the Q is very high, so ance should be stated as being 4Ω, because of overall linearity ameliorated only by slight it’s unlikely to impact on the sound, and I the way it dips below this value above 13kHz. elevations in level at around 100Hz, 700Hz– certainly couldn’t see that it had any effect (In fact, a low and/or diminishing impedance 1.2kHz and in the region 4–8.5kHz, with on the frequency response. at high frequencies is not a desirable trait for this last being sufficiently high in the audio Graph 4 shows near-field microphone any loudspeaker in any case, since it can coax band that it would affect only harmonics, measurements made of the Radiance Three’s a poorly-designed amplifier into instability.) and not the more important fundamentals. midrange driver, as well as of the port behind Although the design presents a comfortable The trace on this graph is actually a compos- it. The output is not what I would have load for any well-designed amplifier, my feel- ite, with the data for the trace below 500Hz expected from a dedicated midrange driver in ing is that you will get best performance from coming from the pink noise response (an a four-driver speaker system with a three-way an amp that will deliver at least its 8Ω rated average of nine individual sweeps) and the crossover. Some of this I attribute to inherent power into 4Ω as well… and preferably more. response above 500Hz coming directly from deficiencies in the particular test methodol- But that really shouldn’t be a big ask. the on-axis gated high-frequency response, ogy used by Newport Test Labs, which is not The final graph Graph( 6) I’ve selected for an expanded and more detailed view of ideal for measuring midrange drivers at the inclusion on these pages is a composite in which is shown in Graph 2. By using the two best of times, and most particularly when it is which all the traces on the preceding graphs graphs, we can see that the overall frequency not possible to isolate the output of the other have been re-scaled by post-processing and response measured by Newport Test Labs for three drivers, as is the case with this design. then ‘fitted’ into the averaged pink noise the Acoustic Energy Radiance 3 comes in at However it does appear to me that Acoustic response, in order that you can see how the 55Hz to 30kHz ±3dB. Other than the slight Energy has only a high-pass filter (and with drivers integrate with each other to produce variations in response at the frequencies a low turnover) in circuit with the midrange, the overall response noted earlier (55Hz to noted, the response is inherently linear, with which I find odd. 30kHz ±3dB.) the spectrum not tilted one way or the other. The impedance modulus (Graph 5) of the Acoustic efficiency of the Acoustic En- Its only other very slight characteristic is a Radiance Three shows where AE has got all ergy Radiance Three design was high, with AD very minor depression around 250–500Hz. that bass energy from, with the enclosure Newport Test Labs reporting a test outcome of Note that all these variations are so small tuned to a very low 37Hz (the two impedance 89dBSPL at one metre, using the lab’s usual that they fall within the ±3dB specification, peaks are at 21Hz and 70Hz). The pair match- very stringent test methodology. This is a so they would ‘characterise’ the sound of the ing is excellent, as you can see from the only higher-than-average result, even though it Radiance Three design, rather than define it. minor differences in the impedance traces comes up a full 1dB short of Acoustic Ener- Graph 3 shows the low-frequency per- of the left and right speakers. Phase angle is gy’s specification. formance of the Radiance Three’s two bass superbly controlled. There is some evidence Overall, I found the measured perform- drivers and dual ports. You can see that the on the traces of that resonance at 950Hz, ance of the Acoustic Energy Radiance Three matching of the drivers is excellent: the small but don’t confuse this with the glitch at to be excellent, even though I also found differences that are visible are mostly caused 1kHz, which is caused by the test instrument several aspects of the design itself a little unu- 65 by the differences in the physical locations switching measuring ranges. I’d be tempted sual, mostly regarding the implementation of of the four elements on the front baffle. to rate the Radiance Three with a nominal the midrange driver. I guess it’s a classic case However you can see also that the upper impedance of 6Ω because the impedance of the proof being in the pudding!

driver is very slightly affected by a resonance stays above this value over most of its operat- Steve Holding

dBSPL dBSPL dBSPL 85 95 95 Newport Test Labs Newport Test Labs Newport Test Labs 80 90 90

75 85 85

70 80 80

65 75 75

60 70 70

55 65 65

50 60 60

45 55 55 40 50 50 35 45 45 30 40 40 25 20 Hz 50 100 200 500 1K 2K 5K 10K 20K 35 35 10 Hz 20 50 100 200 500 1K 2K 5K Graph 1. Frequency response. Trace below 1kHz is the averaged result of nine individual frequency 400 Hz 500 1K 2K 5K 10K 20K 30K Graph 3. Low frequency response of front-firing bass reflex ports (red and pink traces) and upper sweeps measured at three metres, with the central grid point on-axis with the tweeter using pink Graph 2. High-frequency response, expanded view. Test stimulus gated sine. Microphone placed at and lower woofers (dark and light blue traces). Nearfield acquisition. Port/woofer levels not noise test stimulus with capture unsmoothed. This has been manually spliced (at 500Hz) to the three metres on-axis with dome tweeter. Lower measurement limit 400Hz. [AE Radiance Three] compensated for differences in radiating areas. [AE Radiance Three Loudspeaker] gated high-frequency response, an expanded view of which is shown in Graph 2. [AE Radiance 3]

dBSPL dBSPL Ohm Deg 85 95 20 180 Newport Test Labs Newport Test Labs Newport Test Labs 80 90 150

75 85 120

70 80 90

10 65 75 60 9

8 60 70 30 7 55 65 0 6 50 60 -30 5

45 55 -60 4 40 50 -90

35 45 3 -120

30 40 -150

35 25 2 -180 20 Hz 50 100 200 500 1K 2K 5K 10K 20K 10 Hz 20 50 100 200 500 1K 2K 5K 10 Hz 20 50 100 200 500 1K 2K 5K 10K 20K 30K Graph 4. Nearfield frequency response of midrange driver (black trace) and port behind midrange Graph 5. Impedance modulus of left (red trace) and right (yellow trace) speakers plus phase (blue Graph 6. Composite response plot. Red trace is output of bass reflex port. Dark blue trace is driver (red trace). Trace levels not compensated for differences in radiating areas. [AE Radiance 3] trace). Black trace under is reference 4-ohm precision calibration resistor. [AE Radiance Three] anechoic response of bass driver. Light blue trace is sine response of midrange driver. Green trace is nearfield output of midrange driver port. Pink trace is gated (simulated anechoic) response above 400Hz. Black trace is averaged in-room pink noise response (from Graph 7). [AE Radiance Three]

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