AVI Pro Nine Plus Bookshelf speakers you can use on shelves!

With an upgraded design, and designed to work well whether on shelves or even mounted on the wall, these British speakers win over Tony Williams

You want to know what the trouble is with most speakers sold as 'bookshelf' models? They sound horrible on bookshelves! They give a nasty boomy sound if they're used on empty enclosed shelves, and emptied of bass if they're on open racking or surrounded by books. Standard shelf-mounting tends to place the high-frequency drive units too high, making the bass dominate even more and robbing the sound of sparkle, while all but sealed box designs are much too prone to having their sound affected by what's around them.

So what's the answer? Should you wall-mount them on brackets? No, not really: again you're likely to get overblown low frequencies, and unless they're mounted at ear level the balance is likely to be way off neutral. And the most common wall-mount positions — near corners or up near the walUceiling boundary — couldn't be much worse for speakers.

In fact the very best place for 'bookshelf' speakers is actually on good, rigid — and usually heavy — metal stands, these preferably being loaded with either sand or metal shot or the like. The trouble is, this means the small speakers then take up almost as much space in the room as floorstanding designs, which more or less defeats the whole point of them.

British company AVI is one of a growing number of companies to tackle this problem head-on, with a pair of speakers designed to be wall-mounted or used on bookshelves. The Pro Nine Plus has been engineered to suffer a lot less from the boundary effects that can plague so many small speakers, not least by giving the enclosure a front-venting bass tuning port in place of the more common rearexit design, which has all sorts of problems when used too close to a wall or other structure.

There's a conventional driver arrangement, with the 28mm tweeter above the 16.5cm long throw mid/bass driver, the front venting port located alongside the tweeter. Both drive units come from Danish driver concern DST, the Vifa mid/bass unit using a doped paper cone and the 28mm Scanspeak tweeter being a soft dome design, and the speakers are 'handed' — they form a mirror image pair. AVI says the speakers can even be used on their sides in order to fit them into shelves, and to this end there's no badging to look 'wrong' in this orientation.

As the 'Plus' in the AVIs' model designation suggests, this is actually a second generation version of the original Pro Nine design: in the quest for better bass extension and midrange quality along with improved phase characteristics, the new version is taller and wider than the old, but a centimetre shallower front to back. Otherwise the design is much the same, right down to the drivers: the real wood finish is of a high quality, and the speakers are designed to be as easy to connect and drive as they are to place — they're only set up for singlewiring and the sensitivity and impedance make the speakers look pretty undemanding — on paper at least — at 89.5dB/W/m and 8ohms respectively.

Performance

The Pro Nine Plus speakers are designed to complement AVI's new S21 MI Laboratory Series integrated amplifier, but this was unavailable for the test, so they were tried on the end of amps from the amazing Musical Fidelity Tr-Vista 300 (which with hindsight was probably slight overkill!), down to the Cyrus 6 and Harman-Kardon's .E300 HK670. All of these amplifiers are known for being powerful and dynamic performers, but really the AVIs don't need huge amounts of power to deliver a big, open sound, even if the minimum power requirement is a relatively substantial 50W. The trade-off for this is that the speakers are able to deliver plenty of level when required, and that's in no small part due to the quality of those drive units.

I tried the speakers on shelves, both on their side and upright, in each case with the tweeters innermost, and was pleasantly surprised by the open and involving sound they delivered with a wide range of music. These are speakers fully able to deliver a realistic impression of a large orchestra, with plenty of weight to the sound and at the same time fine instrumental timbres and attractive atmosphere. The excellent 'LSO Live' series sounds vibrant and exciting via the AVIs, with the sense of event giving the recordings due vitality and depth, while recordings of smaller chamber forces benefit from the focus and insight with which they're presented.

And that tuning for what are usually considered less-than-ideal placements certainly pays off: The design is relatively simple, but the use of high-quality drive units and a front port makes these speakers adaptable the AVIs sound well balanced when used on stands with a bit of breathing space between them and a rear wall, but they also thrive even in empty but enclosed bookshelves. As I mentioned before, in such locations it's often desirable to pack books around the speakers to minimise the boom, giving a sort of 1960s American den look, but the balance of the Pro Nine Plus speakers doesn't change noticeably whether or not this strategy is employed — the speakers just sound extremely good however they're used.

Managing to wring this kind of bass weight and control out of what are still relatively small speakers — even if they're a bit larger than the miniature monitor norm — is impressive enough a trick; that AVI manages to do this even when the speakers are parked in places I wouldn't even consider when using conventional designs is a bit of magic.

There is no dearth of smallish speakers in this sort of price range, not to mention the fact that this sort of money would buy some pretty serious floorstanding boxes. But the AVI Pro Nine Plus speakers have an appeal all of their own, and I welcome them warmly. 15

A's,1 NINI lit's

Type Bookshelf speakers Price £799/pr

Drive units 28mm soft dome tweeter, 16.5cm long-throw paper-cone mid/bass unit, tuned with front-venting port Sensitivity 89.5dB/VV/m Impedance 8ohms nominal Recommended amplifier power 50-250W

Finishes Black or cherry as standard, others at extra cost Dimensions (H x W x D) 34 x 23 x 24cm

Made by

AV International Ltd., Suites 6&7, Lightpill Mill, Bath Road, Stroud, Glos GL5 30F