Opera Seconda £1295
25th Jul 2007 | 23:00
This elegant speaker opts for sealed-box bass loading
Opera loudspeakers is part of a sizeable hi-fi manufacturing operation based just outside Treviso, in the north-east corner of Italy.
Opera itself is a specialist speaker brand, but shares premises, ownership and distribution with the Unison operation, which makes both solid-state and valve-equipped electronics components. The factory isn't far from the HQ of that other UKD stablemate Pathos, whose Digit CD player is tested next month.
The Seconda might be positioned a bit above the budget price mainstream, but at the very least the extra outlay buys you an attractive finish and an interesting shape.
Available in cherry, mahogany or piano black, the curved sides of the Seconda expand immediately behind the front baffle, and then taper to a slightly narrower back. This is pleasing to the eye, and also helps to avoid focusing internal horizontal standing waves. The front and rear panels, as well as the top, are all covered in leather that looks and feels good, while adding a modicum of damping.
If the finish and presentation of these speakers is unusual, so too is the bass-loading technique. This is a sealed-box speaker, a type that has an illustrious history, but is rarely seen these days, as the overwhelming majority of today's speakers are reflex loaded, (or its close relation, the transmission line).
Port-loading has the apparent advantage of producing more bass output 'for free', through the tuned resonance of the reflex port augmenting the output of the speaker system. However, one has to wonder whether a two-and-a-half-way design, which already has an additional drive unit to supply extra bass, has any real need for ports that do the same job rather less effectively.
The port output might be a freebie, but it comes with some unwanted baggage, such as the one-note tendency of any tuned port versions, a scrambling of phase relationships, and a steeper (12dB/octave) ultimate roll-off rather than the 6dB/octave that applies when the enclosure is a sealed box.
The enclosure here is divided in half, so that each cone driver operates in its own sub-enclosure, and the sides have some extra stiffening.
Sourced from Norwegian specialist SEAS, the two main drivers here look identical, both having 180mm cast alloy frames and 125mm aluminium alloy cones. The tweeter is also a SEAS unit, using a 25mm fabric dome diaphragm.
Floor coupling is unusual yet effective, with a very hefty pair of 10mm spikes just 9.5cm apart supporting the front, while a much wider 28cm steel bar with brass-headed and threaded spikes ensuring good lateral stability. Twin terminal pairs provide optional bi-wiring and feed a fairly complex crossover network, with 12dB/octave upper roll-off to the midrange, and 24dB/octave high pass feeding the tweeter.
It was no real surprise to find that these speakers work best when placed clear of walls. The consequences of sealed-box loading are clearly evident and mostly positive.
Measured under far-field in-room conditions, the overall frequency balance is remarkably well ordered, from the deepest bass (-3dB at 20Hz in-room) right up to the top limit of audibility. Most of the audio range is reproduced within tight /-3dB limits, apart from a -5dB suckout at 70Hz.
There's the merest hint of forwardness in the upper midband, 700Hz-1.5kHz, which will sharpen detail projection a little, plus a mild, shallow dip in the presence zone (around 2.5-3kHz), which should help the speaker avoid any aggressive tendencies. Above that point the treble makes a mild recovery, delivering a smooth and extended ultimate output.
The net result is an impressively high standard of neutrality, underpinned by a bass that is dry but smooth and well extended. Despite its 52Hz fundamental bass resonance falling very close to a major reinforcement mode in our test room, the bottom end remained unusually free from any thickening or 'one-note' emphasis.
The impedance stays above 4.5 ohms throughout, so the load is not unduly difficult to drive. However, our in-room, far-field measurement gives a below average sensitivity rating of 86-87dB (somewhat lower than the specified 89dB), so a reasonably powerful amplifier will be helpful to those who like their music loud.
Pair matching is excellent, right across the frequency band, which speaks volumes about the quality control of both drive units and crossover components.
The impressive measured frequency response is directly reflected in a fine overall sound quality. Primarily auditioned via Naim amplification (NAC 552/NAP 500), Chord Signature cables, driven from a Rega/Linn hybrid vinyl source, Naim CDS3/PS555 CD player, and Magnum Dynalab MD103T FM tuner, the Seconda might not have the most exciting sound dynamically speaking, but it is supremely well balanced overall.
The bass end has plenty of weight and power, driving the music along with a crispness rarely found in ported enclosures, without a trace of thickening, overhang or heaviness to obscure the detail further up the band.
Few speakers are as effective at conveying the contrasting tonal characters of upright acoustic or electric basses, or are able to handle a walking bass line with similar smoothness and consistency.
The midband neatly judges the line between emphasising detail and becoming aggressive. It's essentially neutral and smoother than average, with just a hint of forwardness to project voices well and maintain good intelligibility at low levels.
Criticisms are minor. This is a speaker that does a good job of going about its business without drawing attention to itself. One might perhaps find the top end obvious in the way it makes itself heard, and it could be sweeter and more transparent, but in every other respect this is an impressively discreet design that simply does the job without fuss.
Dynamics could be a little livelier and more invigorating, and subtle instrumental textures are not particularly forthcoming or obvious, as some of the finer micro-detail doesn't come across all that well.
Stereo images are well formed, free from any obvious boxiness and with respectable, if unexceptional, focus and depth, though transparency and dynamic tension are both a little weak.
This is a speaker that succeeds as much through what it doesn't do as what it does: while it may not deliver the most exciting sounds around, it's very careful not to put a foot wrong either.
The beautiful and original presentation goes a long way towards justifying this speaker's price, while the sonic performance provides fine vindication for the use of sealed-box loading in a two-and-a-half-way context.