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Australian HiFi 2000

Legend Acoustics is a company run from the Canberra suburbs by Dr Rod Crawford. The 'Dr' relates to his Oxford D.Phil in solid state physics...not exactly the usual qualifications for speaker design. But after four years as chief speaker designer for the world-renowned Linn Products in Scotland, and as the man behind many of Linn's speakers, he obviously has a talent for the job.

The Equipment

The Kurka seems at first glance to manage with a fairly conventional layout for a centre channel speaker: a pair of 170 mm bass/midrange drivers with a 25 mm dome tweeter between them in a box 200 mm tall by 524 mm wide and 380 mm deep. But whipping off the speaker grille reveals an unusual feature. Instead of a symmetrically balanced speaker arrangement, the tweeter is offset, both towards an edge of the speaker (it should be on the furthest edge away from your monitor since the tweeter isn't magnetically shielded) and towards one of the bass/midrange drivers. Dr Crawford says that part of the reason for this abandonment of symmetrical placement is because of the internal structure of the speaker, with a panel dividing its centre. The other reason is, as he says, 'asymmetry is good'. Certainly one problem with tweeters symmetrically placed between larges drivers is that while dispersion at right angles to the line of speakers is very good, it is not so good in line with the speakers. When the symmetrical arrangement is vertical, as with some main speakers, this matters little. But with a centre speaker it does tend to result in a single 'sweet' spot.

Each of the bass/midrange drivers has a cone diameter of 121 mm, yielding a total area for the speaker of 220 cm**2 (after discounting the 25 mm diameter of the phase plug at the centre of each driver). The bass/midrange drivers are from Audax. The tweeter is a model from Morel. Legend does not take off-the-shelf drivers, but orders unique production runs with the cones specially damped to enable superior integration with the tweeters.

Another unusual aspect of the Kurka has to do with that internal panel in its centre. It is not merely a brace, but fully seals the two halves of the enclosure off from each other. So one of the bass/midrange drivers is in a small bass reflex enclosure (the port is at the back, which may be problematical in some built-in installations) while the other is in a fully sealed enclosure. Thus the benefits of both bass reflex (greater extension of the flat frequency response at the cost of a rapid fall-off below this point) and acoustic suspension (a more gently falling deep response) is achieved.

At the back of the bass reflex side is another panel with about a quarter of the area cut out. The crossover network was difficult to examine, being largely behind this, but it was possible to see two inductors placed with their axes perpendicular to each other. Construction is excellent. Dr Crawford hand solders all joints himself. Wiring is via four substantial binding posts, with shorting links provided for those who dont want to bi-wire

The Kurre `bookshelf' speakers have been reviewed before in Australian HI-FI, but in brief, each uses the same tweeter and just one of the bass/midrange drivers from the Kurka. Actually, this isn't quite correct because while the large drivers in the Kurka are magnetically shielded, those in the Kurre speakers aren't. Despite being two-way speakers, there's a substantial crossover network with two inductors, perpendicularly placed, the larges wound with avide copper strip rather than wire. The cabinets are small (330 mm high by 200 mm wide and 260 mm deep) and are fully sealed. Unusually, they are designed to have the tweeters at the bottom rather than the top. The tweeters are also offset towards the centre.

The Kama speakers, used as surrounds in this package but quite capable of acting as main speakers, are unusual. While they are floor-standers, the top 330 mm of the speakers are almost identical to the Kurre speakers with the same drivers, layout and width and depth dimensions.The remaining 520 mm of height is a separate bass reflex enclosure for an additional rear-firing bass/midrange driver. This portion of the enclosure, which is bass reflex loaded with a rear port, is constructed like a maze with three panels extending all the way across the width and about three quarters of the depth inside, one above, one below and the last one level with the driver.

The Kurlo 2 subwoofers are not an afterthought, as so often happens with the bass end of a home theatre system. Instead, they are probably better thought of as the detachable bass drivers from the Kurre main speakers, albeit supplied with their own amplifiers. Each is quite tall at 710 mm (on their spikes) and deep at 524 mm, but still easy to place because they are a touch under 300 mm awide. They are conventionally rectangular from the floor up to about seven eighths of their height, and then they taper in at about 30 degrees to a width of 200 mm, identical to the Kurre speakers. Thus you can place the smaller speakers on the subwoofers for an integrated-looking set.

The driver action happens in the bottom half, with a single 250 mm long-throw (14 mm) driver supported by two large forward-firing bass reflex ports. The driver's actual cone diameter is 183 mm, giving a cone area, per subwoofer, of 263 cm**2. Each of these is driven by what started as an 'off the shelf' subwoofer amplifier/filter module. Each of these is modified by changes to the fïltering characteristics and the peak performance enhanced by the addition of capacitance to the original 13,600 pF. In addition, a bypass RCA connection and switch has been added, allowing the LFE channel to be fed directly to the power amplifier, skipping the filtering. Unfortunately this also bypasses the volume control, so unless one's surround processor has an extraordinarily avide range of attenuation, it would be difficult to match the output level with the rest of the speaker system. The electronics module provides speaker inputs and outputs in addition to line inputs and line outputs. Lever and filter frequency controls are also provided, along with a phase reversal switch and an on/off/auto power switch.

In Use

One of the advantages of a subwoofer/satellite speaker system (not that I am suggesting that the Kurres are capable of no more than satellite performance) is that you can optimise the positioning of the smaller speakers for midrange/treble performance and do the same for the subwoofer/s for bass performance. A sad fact of physics is that rarely are these positions the same. So I unwired the Kurres from the Kurlos, wired them directly to the receiver, and fed the Kurlos via line level cables from the subwoofer output of the receiver. The Kurres I placed on 820 mm stands, which placed their tweeters at ear level when I was seated on the couch. Instantly I knew I had done the right thing. In stereo mode, the bass achieved a better and smoother balance across the whole sub-100 Hz range. This was particularly noticeable on such tracks as 'Anthem for the Year 2000' from Silverchair's Neon Ballroom which contains such delights as a couple of high-level 26.8 Hz blasts!

Using a pair of subwoofers rather than the more usual one had the pleasing effect of smoothing the bass performance across the room, making precise seating far less critical. In fact I simply could not criticise any aspect of bass performance. It was extremely smooth, powerful, well-extended and tight. There was no need to compromise one frequency band for another. Everything was there, and nothing more abundantly than it should be. What more could you want?

Before moving onto surround sound, I should remark on the Kurre loudspeakers. I largely used an Onkyo TX-DS777 home theatre receiver during this review. In stereo use you have a choice between 'stereo' and 'direct'. In the former mode, it feeds both the main front speakers and the subwoofer. In 'direct' mode, not only does it bypass tone controls and so on it, unlike many, ruts out the subwoofer channel and just feeds the main stereo pair. What was interesting with this speaker system was that when I switched from 'stereo' to 'direct', the character of the sound did not change at all. Yes, the very deep bass disappeared and the normal rest of the below 100 Hz bass was a little quieter, but still the system sounded the same. These do not sound like small speakers. Nor do they sound like sealed speakers, in terms of demanding piles of power. I would regard their sensitivity as about average, which is impressive indeed. These are sweet, smooth and balanced speakers. They tame vocal sibilance, yet remain very accurate. This is perhaps the strongest point of the Kurre speakers: a great midrange and creditable treble performance. Imaging is excellent with a real three-dimensional result.

Then it was time to examine the system in surround mode. The first receiver I used presented me with difficulties. With the subwoofers driven from the LFE channel, of course I set the front main speakers to 'small'. Unfortunately the receiver would not permit me to have 'small' mains and 'large' surround channels. This problem was resolved by giving that receiver the flick and connecting the Onkyo receiver which exhibited no such foibles, and had the added advantage of allowing the delay for the subwoofer channel to be separately adjusted.

The character of sound of the Kurka centre speaker was simply identical to the mains. I found a better result with setting this to 'large' rather than 'small'. Front sound stage precision was excellent, with lateral round panning completely smooth.

I am a fan of high-mounted surround speakers. Yes, I've tried them down lower, but they just don't work as well for me. In any case, even floor-standers tend to lose much of their location due to obstructions from furniture and even other people. So the Kama speakers took their positions on very solid 970 mm tall stands. These were initially in the rear corners of the room, but the bass performance was distractingly boomy. I kept them close to the side walls, but moved them around a third of the way forwards into the room to a position just behind the listening couch. There the balance was just right. Imaging in all surround modes was superb, including the difficult-to-achieve spots between the front and surround speaker at each side. Likewise, sounds sourced from the area within the boundaries marked by the speakers sounded just.right.

Conclusion

Speaker systems tend to be optimised, whether by performance or the listener's placement, for multichannel home theatre or for stereo music. I cannot say this about the Legend Acoustics HTS6 system. They sound superb in both roles. The ability to separate the bars sections from the midrange/treble sections of the main speakers means that performance can be uncompromised in both frequency bands, with the latter brought well forward to produce that shimmering, almost tangible stereo imaging, that makes stereo so enjoyable, while the latter benefit from the extension and power' enhancement or corner positioning. And two subwoofers just do so much to wipe out room resonances, extending the useful listening area to most of the listening room.

Steven Dawson