The name Turbosound is perhaps most readily associated with large concert rigs, but the company also offers a range of compact systems for portable use. Mike Crofts road tests the Impact 120 and 180 enclosures, along with the Impact IA-1400 power amp.

The Turbosound Impact series is a recently introduced range of passive speaker enclosures and a two-channel power amplifier, designed for use in both portable and permanently installed sound systems. There are three speaker models in the range: Impact 80, which uses an eight-inch bass driver matched via a built-in passive crossover to an HF unit; the Impact 120, employing a 12-inch LF speaker with a five-inch HF cone driver; and the Impact 180 bass enclosure, which has a single 18-inch bass driver, is specially designed for use in conjunction with either the Impact 80 or 120 units. The Impact IA-1400 power amplifier completes the range, but the speakers can be driven with any power amplifier of suitable quality.

INSIDE STORY

The Impact range of speakers has been designed with both fixed installations and mobile applications in mind. Turbosound, whose name is usually associated with major installations and very large concert rigs, have produced small cabinets in the past, but this series is the first to be specifically designed and marketed as a truly portable system.

The speaker enclosures are manufactured from moulded polyethylene, and those sent for review were a striking blue colour, which the makers call 'TurboBlue'. As standard off-the-shelf colours, you can choose either blue or grey, but for a larger order, say a complete theatre installation, the cabinets can be produced to order in any colour you care to specify. All this is a long way from the original Henry Ford 'any colour you like as long as it's black' approach, and — from the customer angle — all the better.

All the speaker cabinets in the range are made, according to the supplied user manual, using a "foam-in-place rotational moulding technique". This is basically a two-stage process in which high density polyethylene (HDPE) is first formed in a moulding tool to obtain the rigid outer cabinet skin. A second layer of the same polyethylene follows, but this time combined with a foaming agent which expands the volume of the HDPE to form the inner and much thicker enclosure walls. This produces a cabinet wall of precisely controlled thickness — around 20mm in total in the case of the 180 bass enclosure. The overall result is a very tough cabinet, with good acoustic damping properties, and it doesn't require a fork lift truck or the services of Arnold Schwarzenegger to help you lift it. For the environmentally-minded, the Impact enclosures make use of at least 50% recycled materials in their construction.

The goodies inside the cabs are Precision Devices drive units, all of which (including the bass speakers) have been designed and manufactured specially for use in the Impact cabinet range. Physical protection against accidental damage or prying fingers is provided by a smart black perforated metal grille, which covers the entire front of the cabinets, but reveals the outlines of the drive units and ports beneath.

The Impact 120s are especially interesting, as their HF units are built with five-inch cones, which are designed to give a tight HF dispersion pattern (55 degrees compared with 80 degrees in the case of the Impact 80s) so as to achieve increased gain before feedback for club/live band use. The cones, like a Formula 1 car's brake discs, are made from carbon fibre, which gives great rigidity combined with very little weight — something of obvious importance in an HF speaker. A built-in, passive third order high-pass filter operates at 4.2kHz, below which the 12-inch, 200W (RMS) bass driver takes full responsibility. Overall frequency response is given as 60Hz to 17kHz, with a sensitivity figure of 94dB. The cabinets have built-in pole mount recesses, which accommodate standard 35mm stands, although there are no clamping screws as the pole is effectively a push fit. Mounting or flying fixings are moulded into the back of the enclosures. There are two Neutrik NL4 'Speakon' connectors wired in parallel, mounted on a deeply-recessed plate.

The Impact 80s, which are rated at 125 Watts RMS, contain eight-inch bass drivers together with HF devices of symmetrical design, enabling the speakers to be mounted horizontally or vertically without altering the dispersion pattern. If used in conjunction with the 180 bass units, the manual suggests that the 80s should be run in pairs, that is two to each bass speaker. These eight-inch versions appear to be designed more with fixed installations in mind and are equipped with twin banana plug/screw terminals rather than the Speakon connectors used on the 120 and 180 cabinets. This is a very sensible idea — if you're in the middle of an installation project, you don't want to start having to fit Speakon plugs to the wires hanging out of the wall when you're clinging to the top of a ladder.

The Impact 180 enclosures each contain a single 18-inch bass driver rated at 250 Watts RMS, have a quoted sensitivity of 96dB derived from 1 watt at 1 metre, and weigh in at a manageable, but not inconsiderable, 32.5kg per unit. A passive filter is incorporated into the cabinet, the idea being that a full-range signal is fed in from the power amp, then a high-pass output (above 110Hz) is connected to the Impact 80s or 120s, which sit above on their mounting poles.

Various pieces of hardware are available for mounting and flying applications, and the user manual contains a helpful list of the available spare parts, including re-cone kits. It is worth noting that all the components used in these speakers are UK sourced, so long-term support should not be a problem. It occurs to me that, with the current fashion for 'designer' speaker systems, it would rather defeat the object if anything other than the correct manufacturer's replacement drivers were installed. Therefore the availability of spares and the likelihood of reliable future product support becomes a major consideration when deciding where to spend your money.

The Turbosound IA-1400 power amplifier completes the range, delivering 600 Watts per channel into 4 Ohms. The specification is impressive — frequency response is given as 35Hz to 125kHz at -3dB, with a THD of only 0.06% at rated output from 20Hz to 20kHz. The unit, which is metal-cased, is only 3.5 inches (two rack units) high and very heavy (15kg). The front panel has independent level controls and indicators for each channel, with a single power on/off switch. Round the other side, there are electronically balanced XLR inputs, with Neutrik Speakon output sockets (one per channel), plus the usual IEC mains connector and power fuse. In addition to the female XLR inputs, there are a pair of 'active mode' male XLR outputs; these are used to provide low-pass outputs when an optional active filter card (FC-1400) is installed. These signals would then be connected to the inputs of a second power amplifier used to drive only the bass speakers, thus giving the option of rigging as an active discrete bi-amped system. Among the IA-1400's other features are the output limiters, which optimise the amplifier output to the connected load in order to minimise clipping effects, automatic power-up and power-down speaker muting, and front-panel LEDs which herald the onset of signal limiting and also let you know when the amplifier is operating in active (bi-amped) mode. The amplifier has a separate user manual, which includes a detailed technical specification and various system connection schematics. All Impact systems are supplied with a set of heavy-duty made-up speaker leads.

"...the Impact sound system is, quite simply, the business."

FIRST IMPRESSIONS

The system, which arrived for review, designated the 1280P, is made up of an IA-1400 power amplifier, two Impact 120 speakers, and two Impact 180 bass speakers, complete with four speaker connecting leads and poles for mounting the Impact 120s above the bass enclosures. A full-range output from the power amplifier is fed to the Impact 180 woofers, and the high-pass output subsequently feeds the 120s; if the bass units are not required, the 120s are just used on their own as full-range cabinets. The cabinets and amp were all individually and very strongly packed — the cardboard boxes would make a fairly durable Wendy Village!

The first part of the road test was to involve only the 120s, used as full-range speakers driven from a Spirit Powerstation, so these were duly unpacked first. On the outside of each cardboard box was a label saying 'blue', and I was very taken with the colour even through two layers of plastic wrapping. These speakers are indeed strikingly good-looking and have the appearance of being both serious and stylish. As with many moulded speaker enclosures, these are not your traditional slab-sided boxes and therefore have to be loaded into a vehicle with a little forethought. They seemed to sit quite happily either upright or face down, although I was a little concerned that the small, slightly protruding 'Impact' badge fixed to the front grille would succumb if the cabinets were allowed to slide about.

The integral carrying handles are at the top of the cabinets, which makes carrying them very easy — just like a carrier bag in that the weight is all taken with your arm straight — and I didn't get the usual warning twinges from my back. A brace of 120s is easily light enough to be carried one in each hand, which is fine as long as you don't need to go down any long narrow corridors. Personally, I would have welcomed a second grip at the bottom of each cabinet to allow easier two-handed carrying, for example when negotiating a flight of stairs.

AT THE HOP

The first application involved providing a sound system for a band playing at a barn dance (Lions Club: good attendance, age range, say, 25 to 65, fish and chips included). The event was actually in a real barn but one which had been converted and given a new lease of life as something called a Discovery Centre. My first discovery was that the floor was covered in matting (good), and in addition to a pitched and insulated roof (even better), the interior provided an irregular shape with various side alcoves, and therefore promised something better than the oft-encountered and much dreaded 'community centre' acoustics.

The band PA requirements were fairly straightforward — one vocal microphone (Shure SM58), mandolin via a pick-up (unknown), and a horrible-sounding concertina which needed a microphone (or, even better, a flame-thrower) aiming at either end; all this in competition with a backline of melodeon, guitar, electric bass, and kit. The vocal microphone was particularly important, as on this occasion it was to be used for 'calling' the dances rather than singing, and it was therefore vital to the success of the evening that every word should be clearly heard over the band.

The speakers were mounted on my usual stands and connected up to the Spirit PowerStation in a matter of minutes. I was glad that I had taken the precaution of making up an extra long 'Speakon' lead, as none of those supplied would have reached the far side of the playing area. The absence of pole clamping screws on the Impact 120s didn't matter, as there was enough weight in the speakers to prevent the cables dragging them out of position, and the pole recesses proved sensibly deep. As the band was at floor level and within a few feet of the dancers, I did however hope that no-one would, in their enthusiasm, accidentally push the speakers round to face the band!

As is my wont, I used the CD player (and a Capercaille CD) just to check everything was working properly. From the start, the speakers produced a very smooth, clean sound. At low volume, it sounded like a big hi-fi system, and when the action started, everything remained effortlessly clean, with an especially pleasant top end smoothness. The vocal mic had no trouble maintaining clarity over the top of the instruments, and very little EQ was necessary; even the dreaded concertina didn't sound honky — chalk that one up! The overall sound was noticeably easy on the ears, even at relatively high levels, and I didn't spot anyone sitting at a side table with their hands over their ears looking even slightly annoyed. The best results were obtained with the speakers angled in towards the dance area at about 30 degrees, and the HF coverage of the cabinets certainly seemed to be much more focused than with my usual speakers.

DOWN AT THE CLUB

The second test, in a low-ceilinged club venue, made use of the full Impact system, mixed once again via the Spirit Powerstation, but this time driving the IA-1400 amplifier and both sets of speakers. The event was a sort of all-comers cabaret night, with various performers doing their stuff in front of the house band.

The Impact 120s, 180s, and power amp all fitted into my estate car along with the PowerStation and smaller bits, stands etc. Although the bass cabinets are much lighter than they look, they are not insubstantial. I did manage to load and unload them on my own, but they are best carried with an accomplice if you can find one. The integral moulded handles are sensibly placed about halfway down the sides for two to share the load — each person could then, of course, take an Impact 120 cabinet in their other hand! The Impact 120s sat securely on their poles above the bass speakers, and the whole rig looked unobtrusive when in position, even in such a small venue. If the poles are not required, for example if the bass units are placed on tables, the 120s will mount directly on top of the 180s by means of moulded recesses, which hold the upper cabinet's feet firmly in place.

Two vocal mics, this time for singing, were required, with an acoustic guitar using an internal pick-up fed direct to the desk, plus a Yamaha Clavinova, electric bass (using a line out from a Trace Elliott 1215), and an economically miked kit using AKG D202s on kick and overhead with a Shure SM57 on snare/hi-hat. As the club was fairly small, I decided not to mike up the four-piece brass section, offering them alcohol instead. With floor space at a premium, there was (literally) no room for monitor speakers, so I took a chance and placed the speakers in line with the mics. After some experimentation during the afternoon run-through, I actually managed to place the mics about a foot forward of the cabinets, whilst avoiding their direct line of fire (helped again by the enhanced directivity of the Impact 120s) and obtained a more than ample sound level for both audience and performers.

As ever, setting-up time was limited. This served to reinforce my view that the use of full-range signals driving good quality speakers using resident passive crossovers is an excellent arrangement, as setting-up is greatly simplified, with fewer discrete amplifier channels and shorter cable runs required. Having gone through the usual CD test routine, the drum kit required very little attention to obtain an acceptable sound; kick drum was satisfyingly deep and thumpy, and I obtained a nice discreet click to add definition. The other kit mics were kept quite low due to the small size of the room, and everything kept agreeably to its own part of the spectrum. I spent a few moments listening to the sound coming direct from the bass combo before trying to reproduce it via the system, which presented no problems and resulted in a well-defined and compact sound. Having dealt with the guitar and piano in a similar fashion, a few minutes were spent in balancing the vocal mics, then the band went for a number.

All I can say is that the system handled everything with aplomb, the top end never threatening any degree of harshness, and when I turned up the level, it exhibited a pleasing tendency to just get louder, nothing else. The addition of the Impact 180 bass cabinets gave the sound a degree of depth and power which was felt as well as heard. With the LF crossover frequency set at 110Hz, these enclosures are not aiming only at sub-bass but are designed to take over ail the workload below this frequency from the mid/high units, which I imagine would contribute to increased system efficiency. The band declared themselves very happy with the sound and were very well impressed when I turned the speakers round to face them (still no feedback problems!); they also — like everyone else who commented — particularly liked the appearance of the speaker system.

FLYING COLOURS

To end on a more domestic note, perhaps the toughest test for any portable sound system which I use regularly is its 'hall rating'. This has nothing to do with the sound quality, but it is a test to see how long the speakers are allowed to stand in the hall at home without provoking critical remark. Now you may scoff all you like, but this is no joking matter, especially when one is considering postponing the kitchen refurbishment project in favour of one involving new (blue, actually) speakers. So far, not only have the pair of Impact 120s managed to survive without threat of eviction, but they have actually been awarded a 'nice colour' verdict from my wife's mum!

In conclusion, the Impact sound system is, quite simply, the business. It delivers all the goods, and just goes on delivering — here is 1200 Watts of super-smooth power in an attractive and practical package. The speakers in particular are extremely stylish and sound effortlessly smooth, plus the whole thing has enormous credibility.

Turbosound Limited, (Contact Details).