THE five loudspeakers in this review fall into the price range of £70 to £170. All reflect in one way or another various current trends in 'bookshelf' design and all except one are British designed and built, despite the fact that Rotel has its home base in Japan. The exception is the diminutive JBL Control One which was developed and is manufactured at JBL's headquarters in California. Interestingly this model stands apart in several other respects too, but more of that later on.

For a review of this nature it makes good sense to employ a group of listeners, to obtain a consensus of opinion and to help make the auditioning as objective as possible. Thus it was that John Borwick, Geoffrey Horn and myself repaired to the new listening room at the GRAMOPHONE offices in Harrow just after Christmas armed with a selection of known recordings. As is our usual practice, each test began with a single loudspeaker from a pair auditioned on a suitable stand some two metres away from the room walls. Pink noise was used as a source to start with. This gives a very good idea of the overall tonal quality of a loudspeaker, allowing one to pick out very readily any anomalies in the unit's in-room frequency response and providing an excellent guide as to its dispersion characteristics. This was followed up by a known recording of speech before setting up the second speaker and moving on to fully-fledged stereo listening. The impressions formed in this way provide a very reliable indication of a speaker's overall performance and are almost always confirmed by the subsequent listening to a stereo pair. Our reference for reproducing the pink noise was a single Quad ESL-63. As has been stated many times before, such a reference is essential in this kind of test where the review models are tested sequentially rather than by A/B listening; it also enables us to establish consistent dynamic levels on programme material, the importance of which can never be over-stressed.

We used very high quality ancillary equipment for the tests and a selection of recordings, both on LP and Compact Disc which was guaranteed to tax the speakers' abilities in every respect. Included was the Schubert An die Musik, D547 (Dame Janet Baker/Geoffrey Parsons – EMI LP A5D4054), Respighi's Belkis, Queen of Sheba (Philharmonia/ Simon – Chandos CD CHAN8405), Mozart Symphonies Nos 32 and 35 (Orchestra of the Eighteenth Century/Brüggen—Philips CD 416 490-2PH), Rossini's Stabat Mater (Ricciarelli / Terrani / Gonzales / Raimondi / Philharmonia / Giulini – DG CD 410 034-2GH) and a pop track from Dave Grusin's Discovered Again (Sheffield Lab CD-5).

Differences in sound quality are very marked when it comes to loudspeakers and never more so than at the lower priced end of the market, as represented by the models considered here. The constraints imposed by a specified retail price mean that the designer has to use all his ingenuity in juggling with the various options and compromises. Enclosure size, the type and quality of driver units, the type of cabinet finish—all these are affected and all determine the end result in domestic surroundings.

Castle Durham

Manufacturer: Castle Acoustics Ltd., Shortbank Road, Skipton, N. Yorks BD23 2TT. Price: £169 per pair.

CASTLE have maintained an impressive record for the quality of their loudspeakers, and previous models tested (e.g. the Pembroke and Lincoln in June 1983) have done very well. The Durham slots in towards the top of the so-called budget end of the market and is the most expensive model (just) in this group.

Immediately striking is the extremely high quality of the cabinet, which is constructed from 19mm chipboard and finished on all six sides in a quality real wood veneer (various grains are available and our pair was in mahogany). The Durham is a two-unit design using Castle's own drivers, a 130mm high efficiency bass/mid unit with a flared pulp cone and a 30mm ferrofluid damped plastic cone tweeter. A reflex loaded design, it carries a 32mm diameter port on the back panel which tunes the 15-litre enclosure to around 65Hz, this technique helping to 'prop up' the bass response as the driver's natural bass extension tails off. The enclosure is internally braced to keep the panel resonances under control and is lined with bitumous pads and acoustic foam to moderate the deleterious effects of standing waves. The crossover is a second order, 12dB/octave type using film capacitors for the tweeter components. The front grille is of contoured plastic foam held in place by a "Velcro"-type strip running around the perimeter of the front panel. When properly in place this looks neat enough, but of course its primary asset is that it has comparatively little effect on the sound, unlike too many other types of cover. Electrical connections are made via the usual, well regarded 4mm socket/binding posts which are mounted proud on the rear panel. These can take the appropriate plugs, spade connectors or bare wire ends.

Our pink noise test showed that the Durham has a very even and wide axial response with fairly low coloration. There is a slight hardness to the treble but the bass falls away rather too obviously despite the reflex loading. Apart from this lowend deficiency, however, the Durham gave a very good account of itself. The clarity of the treble and the overall presentation of the sound-stage were consistently remarked upon and although there was some obvious compression at exceptionally high levels it should be emphasized that for most kinds of music in a moderate-sized room the Durham will perform well. Its sensitivity is good at 89dB/W at one metre and its impedance characteristic represents an easy load for the amplifier, nowhere falling below 6 Ohms. This is a civilised loudspeaker, beautifully finished. Its bass-shy response can be ameliorated somewhat by placing it fairly close to the rear wall (not too close because of the rear-firing port), indeed the manufacturer recommends such positioning. It should certainly be high on the auditioning list and can be safely recommended.

Goodmans Maxim

Manufacturer: Goodmans Loudspeakers Ltd., 2 Marples Way, Havant, Hants P09 1JS. Price: £70 per pair.

MANY years ago Goodmans had a range of loudspeakers each of whose name began with the letter M (just as KEF had a range beginning with C and B&W had models which started with D). There was the Magnum and the Mezzo, the Mambo and the Marimba, but it was the Maxim which stood out. It quite rightly earned widespread recognition as a high fidelity bookshelf model of truly diminutive proportions (267X 140X I84mm). It could generate a really impressive sound despite the small size of its driver units (it had a very long-throw bass/ mid driver of notably poor efficiency but spectacular ability). Goodmans have recently been releasing new models with those old names, We have seen the names Mezzo and Magnum and now a new Maxim has been introduced. The new model bears precious little physical resemblance to its predecessor and even though it is very small it is still some 31% bigger in overall size. In real terms it is also much less expensive (£70 now compared with £20 7s. 9d. in 1971).

The Maxim's cabinet is made from vinyl covered 15mm chipboard and measures 260 x 170 x 205mm. It uses two drive units, a 130mm flared pulp cone bass/mid driver and an Audaxmade 12mm plastic cone/dome tweeter which is ferrofluid damped. At the top rear of the cabinet is a 32mm diameter reflex port (the original Maxim was a sealed box, infinite baffle design). The front grille is a fabric-covered chipboard frame which push-fits on to the enclosure via plastic posts. Polyester fibre wadding provides internal damping. Electrical connections are made via 4mm socket/binding posts in a recessed panel.

Pink noise shows up some obvious shortcomings in this design which are only to be expected at the price. The bass, not surprisingly, falls away very rapidly below about 120Hz. The treble, though lacking in extension, is clear and well focused subjectively (the more so when the front grille is removed), although it does seem somewhat emphasized. This is because it isn't balanced by any real bass weight and what there is sounds by comparison to lack body. The Maxim offers good clarity and a good presentation of the stereo sound-stage, and provided one doesn't want to play too loud it can handle most types of recorded material quite comfortably. Its sensitivity is a little below average, at 85.5dB/Watt at one metre but its impedance holds up well throughout the bandwidth and thus represents an easy load. Amplifiers of 20 Watts per channel and above, up to about 50 Watts would be well matched to it. Unpretentious but surprisingly 'gutsy' the Maxim offers a quite respectable sound for the money and in its price area scores very well.

Tannoy Mercury II

Manufacturer: Tannoy Products Ltd., The Bilton Centre, Coronation Road, Cressex Industrial Estate, High Wycombe, Bucks, Price: £150 per pair.

THE biggest loudspeaker in this group, the Tannoy Mercury II is an updated version of the model which has been receiving widespread recognition since its introduction. In addition to this Mk. II version, the original Mercury has spawned the more expensive M20 Gold model. The new Mercury is a little taller than its predecessor and the tweeter, which was previously from the Audax range, has been replaced with one made by Tannoy themselves. This is a 25mm polyamide dome unit and it complements a 150mm polypropylene-coned bass/mid driver also made by Tannoy. This and the crossover have undergone substantial changes so in effect the Mercury II is an altogether new model.

The cabinet is fabricated from 13mm chipboard and finished in a simulated wood vinyl (the review pair being in a smart 'black ash'), this being particularly well finished. The enclosure sports a 50mm diameter reflex port at the bottom of its front panel, this augmenting the low frequency output in the usual way. The crossover is designed around 12dB slopes and electrical connection is via the now usual 4mm socket/binding posts which are located in a fitting which is set in to the back panel. Internal bracing is used to prevent the enclosure from flexing and acoustically resistant fibre wadding lines the inside. The front grille is a fabriccovered chipboard frame with the usual push-on type of fitting.

We found that the grille softened the treble rather and slightly 'spread' the directivity, and preferred the sound with it removed. On-axis the speaker gives a well balanced output with no obvious peaks but a rather warm overall tonal quality with a marginally 'boxy' coloration. The HF seemed on the bright side although the extreme top appeared a little rolled off. Off-axis the sound fared less well, emphasizing the brightness, particularly, and understandably, with the grille removed. The bass end was quite the best of this group, with fairly good extension and weight, especially for an enclosure of its size. The female vocal section we used from the Rossini – the two-soprano duet "Quis est homo", which is a particularly cruel test – revealed some edginess and a constricted effect, but otherwise fared well. The limited axial response does tend to compromise the stereo detail for listeners away from the main firing line but other than that few criticisms were made. The dynamic qualities of the pop music disc were particularly well conveyed. The impedance dips to just under 4 Ohms at one point but as the sensitivity is good, at 88dB/Watt at one metre, no especially powerful amplifier is needed. All things considered, the Mercury II achieves a nice balance of compromises, offers an exceptionally good performance for the price and should certainly be heard by anyone in the market for a model at this level.

Rotel RL850

Manufacturer: Rotel Hi-Fi, 25 Heathfield, Stacey Bushes, Milton Keynes, Bucks. Price: £109 per pair.

DESIGNED and manufactured in Lithe UK, the Rotel RL850 is a two-unit sealed cabinet ('infinite baffle') model using a British-made Elac 150mm pulp cone bass/mid driver together with a Peerless 25mm soft dome tweeter. The enclosure is made from 15mm chipboard and covered in the familiar simulated wood vinyl laminate. Internally a very simple four-element crossover network is employed and a generous amount of acoustic wadding is fitted to help control the box resonances and break up standing waves. The grille frame is of 13mm chipboard, fabric covered and fixed with the usual push-on plastic retainers. Electrical connection is via the 4mm socket/binding posts which seem to have become de rigeur now for most loudspeakers and amplifiers which have any kind of hi-fl aspirations. These are let-in to the rear panel on a rebated plastic plate.

Pink noise revealed that the tweeter was very directional so that one doesn't need to be far off-axis for the treble energy to fall very significantly. On-axis there is some treble emphasis and it tends to 'fizz' at the extreme top, which gives an uncertain, pinched quality to voices and spoils the fine resolution of the stereo sound-stage, although in most respects this placement aspect is quite well managed, probably aided here by the tweeter's tendency to beam. With complex orchestral music, particularly when it is also loud, the fine detail is much less clearly defined than one would like, but with simple textures, and especially with the pop music track, the RL850's crisp response and lively dynamic qualities were certainly appreciated. The bass end is a little coloured and it rolls off fairly obviously, although what there is is tight and well controlled. The sensitivity is high at 87dB/Watt at one metre and the impedance characteristic an easy one, so that the speaker could happily partner almost any amplifier intended to drive nominal 8 Ohm loads; it can, however, cope with high levels without stress. If this looks like a list of negative qualities with a redeeming footnote it should be noted that at its price the RL850 offers a good deal more than many competing designs at around the £100 mark. Its tonal balance is reasonable, if not as accurate as one would like, and it has good dynamic properties. It may not suit all classical music lovers' tastes but it should be considered.

JBL Control One

THE Control One is something of a novelty; certainly it stands apart from the other models in this report. JBL call it a "personal monitor loudspeaker" and it is intended to bridge the gap between domestic and professional applications, being aimed at situations as diverse as shops, bars and other such leisure venues as well as for use in the home and for pro fessional sound engineers either on location or as a "nearfield" monitor in the studio. Quite a list! Easily the smallest of the speakers auditioned here, the Control One measures just 226x 152 x I43mm. It is a two-unit reflex-loaded model using a 19mm synthetic cone/dome tweeter and a 90mm doped fabric bass/mid driver. It is the cabinet which immediately sets this model apart, however. This is fabricated from moulded polypropylene structural foam with rounded corners. It is finished in plain black and has black rubber end caps which doubtless further damp out any unwanted resonances emanating from the already very rigid cabinet. A small 22mm reflex port is sited on the front panel and the grille is of perforated metal which wraps around the baffle and is held in place by its edging trim, which is again made from rubber. At the rear are springclip connectors for the input signal (of the type which cater for bare wire ends) and several moulded indents to which can be fitted various optional fixings to enable the speaker to be used on wall brackets or even on a tripod camera-type stand. The crossover is centred on 6k1-1z and uses high quality components. The frequency response is claimed to be within 3dB limits from 120Hz to 20kHz and the impedance is a nominal 4 Ohms.

Pink noise indicated a speaker with a reasonably even response, as far down as it goes, with an asymmetric lateral dispersion characteristic which is almost certainly due to the laterally offset tweeter position on the front baffle. Spoken male voice predictably lacked 'body' but female singing voices were remarkably plausible in the lower registers, this positive aspect being countered by a hardening of the sound with increasing pitch and by a somewhat nasal quality compared with the reference. The loud and complex orchestral music of Respighi had reasonable clarity and plenty of energy but the sound hardened considerably and of course the bass end, which disappears very rapidly below 100Hz, was no more than a token presence. The speaker scored surprisingly well on the Rossini passage we used, the two female voices of the soloists being well articulated and readily distinguishable—rather more so, in fact, than with most of the other speakers in the group. The energetic pop track showed good, crisp definition and tight control, again excepting the purely nominal bass presence.

Despite its obvious limitations in tonal balance and frequency extension the JBL Control One offers a remarkably detailed and analytical sound and unusally high power handling, and one can well envisage its considerable value as a portable monitor. Domestically it could find a place in modest, compact systems where its bandwidth limitation and somewhat forceful character can be moderated or accepted. It offers a lot for the price and deserves to be heard by anyone looking for a virtually indestructible mini speaker.

Ivor Humphreys