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MJ Acoustics Pro Cinema 1 & Pro 50

Passive Surround Monitor System & Active Subwoofer
By Hugh Robjohns

Looking to experiment with surround sound but on a tight budget? This new system could provide the opportunity you've been looking for.

The whole surround sound movement, if I can call it that, is a godsend to loudspeaker manufacturers — instead of selling two boxes at a time they can now sell five plus a subwoofer! However, whereas the audio geeks among us might happily re-equip to enjoy the wonder that (sometimes) is surround sound, the 'domestic managers' in our lives may object to ever more ugly boxes cluttering up the living room. In a dedicated studio that particular issue may be less of a problem, but there is no getting away from the fact that more speakers means more clutter and more cost.

If you want to investigate surround sound without investing in a high-quality 5.1 monitoring system at this early stage, the MJ Acoustics solution may well provide an ideal stepping stone.If you want to investigate surround sound without investing in a high-quality 5.1 monitoring system at this early stage, the MJ Acoustics solution may well provide an ideal stepping stone.Photo: Mike CameronIt is hardly surprising, therefore, that many loudspeaker manufacturers are working hard to produce small, neat, inconspicuous, and good-quality speakers for surround-sound applications. The favoured solution seems to be to use mini-satellites for the five surrounds, plus a matching subwoofer to handle all the lows. Clearly though, some form of bass management is required to redirect low-frequency energy from the five surround channels to the sub, along with the LFE channel itself. Fortunately, most hi-fi surround amps and controllers provide this facility as standard.

MJ Acoustics, a UK manufacturer primarily of active hi-fi subwoofers, has recently launched just such a system — its first to provide full range monitoring. Unusually, the Pro Cinema 1 system was designed to expand upon the growing reputation of the company's subwoofer range — most speaker manufacturers design the main speakers first and then think about a sub to hold up the bottom octaves. Essentially, what is on offer in the Pro Cinema 1 system is four very compact infinite-baffle two-way satellite speakers, plus an identical (but horizontally purposed) matching centre speaker, and an equally compact dedicated subwoofer. The Pro Cinema 1 speakers are available in satin black or silver finishes as standard, although optional wood veneers are also available to order.

Being infinite-baffle designs (ie. no ports), the satellite speakers are very tolerant of positioning, and the cabinets incorporate keyhole slots to facilitate simple wall hanging. Indeed, placement against a rear wall is key to developing an accurate frequency response. Suitable Rawlplugs and screws are provided for wall hanging, and small self-adhesive rubber feet for shelf mounting. Combine the wall hanging option with their diminutive size, and it can be appreciated that this is a system which can be 'lost' quite easily in most rooms. The subwoofer is also much smaller than the average, and is well equipped with room-tuning facilities to allow it to be positioned out of the way, whilst still doing its job properly. But I'm getting ahead of myself a little here — lets take a closer look at the details.

Vital Statistics

The striking aspect of the Pro Cinema satellites is their tiny size and low (2.5kg) weight. The baffle dimensions are a reasonable 160mm wide by 230mm high, but the cabinets are a surprisingly shallow 115mm — providing an internal volume of about four litres. The cabinets are constructed from 15mm MDF and lined with acoustic wadding to damp out internal resonances. The baffles have well-rounded edges to minimise diffraction, and the drive units are protected by a removable fabric grille which stands proud of the baffle on four pegs.

MJ Acoustics Pro Cinema 1 & Pro 50
pros
  • Very compact.
  • Well constructed.
  • Smooth, refined sound.
  • Impressive performance for size/cost.
cons
  • Requires multi-channel amplifier with bass management facilities.
  • Limited tonal and spatial resolution.
summary
Attractive, compact satellite and subwoofer system which is capable of good results in a discreet and very cost-effective way. Although not intended for reference monitoring, it offers a pragmatic first step on the ladder for anyone wishing to experiment with surround sound.

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The satellite's cabinet houses two drivers: a one-inch soft-dome tweeter with neodymium magnet and a four-inch pulp-paper-cone bass/mid-range unit. Both are manufactured by Vifa and are magnetically shielded. The terminal panel on the rear is fitted with standard 4mm binding posts and supports the small seven-element passive crossover. The only difference between the four satellites and the centre speaker is the orientation of this connector panel. The crossover specifications are a little vague, but the implication is of a 6dB/octave slope for the tweeter and 12dB/octave for the woofer, crossing over at 2kHz.

The speakers are rated for 100W peak power handling and present an 8Ω nominal impedance. They are also relatively efficient, with a sensitivity of 88dB per Watt at one metre, so you don't need a particularly powerful amplifier to get them going. The quoted frequency response is a slightly optimistic 60Hz to 25kHz, and no limits are given.

The subwoofer cone fires downwards.The subwoofer cone fires downwards.The active subwoofer has inputs for both line-level and high-level (speaker) sources — supporting either mono or stereo signals in both cases. The rear panel carries all of the interfacing and controls — with a pair of phono sockets for line-level inputs and a Neutrik Speakon for the high-level speaker inputs. When used with a surround-sound amplifier equipped with bass management, the line-level input(s) would be used, connected to the appropriate subwoofer output(s) of the surround controller.

However, in less sophisticated installations an optional cable can be supplied to make use of the high-level speaker input. This cable is terminated in a Speakon at one end, and bare wires at the other can be connected to the appropriate amplifier terminals feeding the left and right speakers. Although convenient, this configuration does nothing to increase the power handling of the satellites, or to optimise the integration between the sub and satellites. In contrast, many subwoofer systems are designed to be wired directly to the amplifier and to pass on a high-pass filtered signal to the satellites, thereby increasing the power handling of the latter as well as ensuring an optimal crossover between satellites and subwoofer.

However the subwoofer is connected, the input sensitivity can be adjusted by independent level controls for the line and high-level inputs. There are two further controls to set the low-pass filter turnover frequency (40-240Hz) and the relative phase (0-180 degrees). The final panel facilities are a fused IEC mains inlet and an on-off rocker switch. This panel also acts as a heat sink for the amplifier, but never became more than warm during my trials.

The rear panel offers controls which ease integration with the satellites.The rear panel offers controls which ease integration with the satellites.The over-engineered internal MOSFET amplifier contains an active protection circuit to prevent possible speaker damage with high levels of subsonic signal, and is capable of producing peaks of around 80W. This is a high-efficiency design, so don't let the thought of 'only 80W' worry you! The amplifier drives an eight-inch long-throw woofer with a double-magnet motor system, firing directly downwards to the floor — from which it is separated by four short corner legs. The chassis and cone surround are heavy-duty designs specifically intended to cope with the kind of punishment a speaker in this role has to suffer.

The sealed cabinet, with a black satin finish as standard and wood veneer as an option, is constructed from 18mm MDF and measures a compact 332 x 278 x 278mm (hwd) — about 25 litres. It only weighs 8.4kg as well, so is easy to manoeuvre around the room to find the position which supports the smoothest low-end reproduction.

Using The System

Setting the system up is simple enough, given a suitable multi-channel amplifier, and the satellite speakers sound well balanced when placed with their backs to a wall (although it is sensible to keep them away from corners). I started with the subwoofer's filter set to its minimum 40Hz and gradually wound it up until I felt the crossover between sub and satellites was optimal. It worked out somewhere around 90Hz, judging by the extremely vague panel markings. Setting the level was a case of matching by ear and then backing off a couple of decibels. I have found from experience that I can now get virtually as good a result doing that as faffing about for half an hour with a pink noise source and a sound level meter! I also find I can get a very good impression of the overall balance if I listen to the system from another room — it's amazing how well that works.

Adjusting the relative phase of the sub is a process of trial and error which often involves a lot of iteration with the level and crossover settings, but getting it right really helps a sat/sub system to sound properly integrated, for example with the transient and body of a kick drum belonging to each other instead of being separate entities.

Overall, I found the Pro Cinema system sounded very smooth and listenable, and the subwoofer could be encouraged to integrate very well. I have to say I found reverbs and room acoustics hard to discern, and the system lacked the kind of detail needed for critical listening. Obviously, though, these are not intended to serve as reference monitors — and they aren't priced to be, either — so the limited resolution and rather two-dimensional imaging are to be expected. Having said that, these satellites cost £100 a box in the UK — we're talking JBL Control One territory here — and the Pro Cinemas look and sound a lot nicer!

Listening to some dramatic DVD film soundtracks, the sub really does the business, providing fast transients and thrilling low-end rumbles where necessary, all without complaint, and the satellites create an enjoyable sense of envelopment. I wouldn't want to run the system at high levels in a big room, but in an average-sized British living room there is more than enough to go around here. Should more volume be an issue — either in terms of levels or space — the company make a larger compatible subwoofer, the Pro 100. While I found that some of the more subtle sonic details of complex soundtracks were lost in the overly 'nice' presentation, the general impression was of a well-balanced, smooth sound which was always pleasant to listen to.

If you want to investigate surround sound without investing in a high-quality 5.1 monitoring system at this early stage, the MJ Acoustics solution may well provide an ideal stepping stone. It is very neat and discreet, well built, easy to set up, tonally balanced, pleasant to listen to, and cost effective. It isn't particularly revealing — tonally or spatially — but if you already have decent stereo monitoring these aspects may be less of a concern when experimenting in surround presentations.

information
infop.gif Pro Cinema 1 five-speaker satellite set: black/silver finish £500; cherry wood veneer £600. Pro 50 subwoofer: black/silver finish £299; cherry wood veneer £379. Pro 100 subwoofer: black/silver finish £599; cherry wood veneer £699. Prices include VAT. Other wood veneers available on request.
infot.gif MJ Acoustics +44 (0)8707 445080.
infof.gif +44 (0)8707 469380.
infoe.gif sales@mjacoustics.co.uk
infow.gif www.mjacoustics.co.uk
Published December 2002