For professional applications, the powered mixer was once a non-starter. But as technical obstacles have been overcome, so the format has become newly viable. Nigel Lord road-tests the Soundcraft Powerstation, to see whether it makes a silk purse out of a curate's egg

Getting a band out of the bedroom and onto a stage has always been fraught with problems. Problems with mains supplies are common, and problems with backline amplification are an everyday occurence. Problems with hi-tech gear have occupied the minds of musicians for years, while problems with roadies are the stuff of legend. Nothing, however, can compare with the problem which must at some time have affected every musician that has ever trod the boards — the problem of PA systems.

Whether it's a PA that simply isn't up to the job, the guy on the mixing desk who's never heard your music, or the monitoring system feeding you misleading signals, PAs are usually bad news. Where human error is concerned there's little comfort to be given, but where technical difficulties raise their head, there's always something you can do to ease the process of getting a PA up and running.

As any engineer will tell you, the main source of problems with component systems is the hardware which connects them together. Because users seldom venture inside a piece of equipment, the chances of it breaking down because of internal failure are drastically reduced. Conversely, because users have everything to do with the way equipment is connected, the chances of problems occurring are drastically increased — particularly under stage conditions where the pressure is on, and mistakes can be made.

One solution is to enrol on an electronics course and study the subject for two or three years, so that you know exactly what you're doing the next time you wire up a PA system. The other solution is to buy equipment where connections are kept to a minimum, by combining it into a single cabinet. Like a powered mixer, for example...

Theory

The concept of the powered mixer is by no means new. The very earliest PA amps were effectively small mixers built into the same casing as the amplifier itself. The problem was, rather like hi-fi systems at the time, the design of all-in-one units, while making them less trouble to set up, tended to involve major compromises in sound quality.

But recent advances in amplifier and digital technology have led to the re-emergence of combined mixer-amplifier systems — often including built-in digital effects — to answer the needs of smaller bands who value the convenience of an all-in-one system, but don't want to compromise on quality. Over the past couple of years, we've seen designs for powered mixers from the likes of Studiomaster and Peavey, offering professional mixer specifications and relatively high power.

Relatively new to the mixer market, Soundcraft already have three dedicated live mixers in their Spirit line-up; the Live, the Live 4 and the Monitor models. Their entire Folio range could also be used as live desks, particularly where fewer input channels are required and/or space is a consideration.

But powered mixers represent a new departure for the company.

First impressions

If looks are anything to go by, it's an impressive start. With a top panel which could only be that of a Soundcraft Spirit desk,the Powerstation seems particularly well appointed for a live mixer of its kind. A 12:2 configuration, it provides eight mono input channels plus two stereo inputs, and includes two auxiliary send buses, 3-band channel EQ with sweepable mid-range, stereo 7-band graphic EQ, built-in Lexicon digital effects processing, phantom powering, 2-track return inputs plus monitoring.

The amplifier is a 265 + 265 watt stereo design, fed via a small patchbay just above the Master section. Each of the mono input channels is identical, and offers mic (XLR) and line (1/4" jack) inputs, with an additional stereo jack providing an insert point, plus a gain control to ensure accurate level matching across a range of input devices.

In addition to the rotary controls, each EQ section also includes a 100Hz bass roll-off switch — actually a 3rd order, 18dB/octave high-pass filter — for removing low-frequency popping from mics, stage rumble and low-frequency hum. The EQ controls themselves provide 15dB cut and boost at low, mid and high frequencies — the mid frequency range being adjustable from 250Hz to 6kHz.

Auxiliary 1 is switchable either post-fade, where it can be used with an external effects processor, or pre-fade, where it may be pressed into service as a foldback or monitor feed. Auxiliary 2, by contrast, is always configured post-fade, and provides the source of the signals for the built-in Lexicon effects. These may be switched in or out for each channel, making it possible to access an additional external device in place of the on-board processor.

The Pan control does what pan controls have always done, as do the channel faders, though it's probably worth mentioning that the latter are linear in operation, and offer 10dB of gain above the 0dB mark. Finally, the PFL button, when pressed, feeds pre-fade signals to the monitor section, where they may be selected as a source for the headphones or meters.

The stereo input channels, though essentially the same in terms of layout, offer slightly fewer facilities with only line level inputs (via two mono jacks), no insert points, no high-pass filter and static midrange controls.

On the busses

Because the Powerstation is a live mixer (though you could, of course, use it for recording to two track), no group buttons are included; each channel is automatically bussed to the main L/R output pair, controlled only by its Pan position within the stereo field. As a result, the master section is quite straightforward, both to look at and to use.

Output level is controlled by a parallel pair of faders positioned alongside the Effects master fader, which determines the output (return) level of stereo effects signals from the on-board Lexicon processor. These are fed directly into the main L/R mix. Additionally, the Effects To Aux 1 control allows you to mix (in mono) the output from the Lex with the Aux 1 sends, should you wish to provide a wet mix for foldback.

Aux 1 and 2 Master controls are used to adjust overall signal levels sent to Auxiliary 1 and 2 outputs, whilst Stereo Return and 2-Track Return provide control over stereo signals entering via the Stereo Return jacks and the 2-Track phono sockets located in patchbay immediately above the Master section.

Additional controls adjust monitor and power amp input levels, and there are switches to route the 2-track return to the main L/R outputs, and to send a pre-fade signal to the monitor, which itself may be switched to either main L/R signals or pre-fade signals as the source for the headphones and bargraph meters.

With its own set of inputs and outputs and Bypass buttons, the graphic equaliser is effectively a discrete section of the Powerstation which can taken out of circuit. However, the inputs to the graphic are 'normalled' to the main L/R outputs, and its outputs are normalled to the inputs of the power amps. Plugs need to be inserted into the patchbay jack sockets for these connections to be broken.

"I found performance to be virtually identical to the Folio, which is pretty damn good in my book"

With only seven bands of equalisation at 64Hz, 160Hz, 400Hz, 1kHz, 2.5kHz, 6kHz and 15kHz, it's debatable whether this can even be described as graphic equalisation — but I suppose car hi-fi manufacturers get away with it, so we won't quibble. What I do take issue with is Soundcraft describing the very limited 6dB of cut and boost provide by the sliders as being somehow superior to the 12 or 15dBs provided by other units. Such high levels, they claim, can lead to feedback or similar unwanted effects occurring with deceptively small movements of the faders.

Now even if there were any other 'unwanted effects' which are similar to feedback, would the 15dB boost provided by the individual channel EQs not be just as likely to produce them? And if so, why limit the graphic EQ in such a way? It may not often be necessary to boost frequencies by more than 6dBs, but I could think of a number of environment conditions which would demand that you reduce certain frequencies by more than 6dBs. Don't forget that 3dB is considered a single increment on most volume control scales. Presumably the fear is that being sliders, they could be easily knocked, but positioned where they are on the desk this seems rather unlikely. Anyway...

Other powered mixers include digital effects processors, but the Powerstation is the only one sporting a designer label. It may be designed by Lexicon, but it's a pretty basic affair, offering a menu of just eleven reverb programs, plus an Effects setting, which leads you to a further rotary switch with an additional eight programs (see boxout). In addition, there's a Dark/Bright switch to control the characteristics of the reverb programs, and an LED-style input trim control, to prevent high signal levels clipping.

The power amplifier delivers its 265 + 265 watt load into 4 ohms, and incorporates a useful protection system with LED status indicators on the top panel. It is designed to protect the output transistors, by isolating the speaker outputs if a damage condition is detected. This it does by means of relays which flip over before any permanent damage occurs, lighting the orange Mute LED in the process. The Mute LED also lights momentarily after power up, when the output relays are opened, to prevent power surges damaging speakers.

There is further protection in the form of a vari-speed fan, which delivers increased air flow to the amplifier as output level increases. Again, there's an LED to warn you of increased operating temp, which can easily occur if clear airways are not maintained at the front and left-hand rear side of the desk.

This makes it all the more surprising that the Powerstation has been made rack-mountable. OK, so no damage is going to result from overheating — but there's the damage to your ego if the relays trip and you're left in silence. Frankly, if you can't mount the Powerhouse in its own heavy-duty rack with the necessary holes for through ventilation, I wouldn't rackmount it at all.

On the road

OK, so now you know what Soundcraft have put into the Powerstation, let's look at what you can expect to get out of it. First and foremost with any high quality mixer is its audio performance. Oddly for an otherwise informative and useful manual, only selected performance specifications are included. Noise is quoted at -80dBu for the main outputs, and -83dBu for the auxiliary outs, and total harmonic distortion at <0.009%, but other than that one has to rely quite a bit on one's ears.

My experience as a user of a Soundcraft desk is limited, I'm afraid, to a small Spirit Folio desk which I borrow from a friend whenever I'm mastering from ADAT down to DAT, or copying between DAT and cassette tape. I use this in preference to my main 16-channel desk partly out of convenience (I hate having to set and reset mixer level, EQ and auxiliary controls), but also because I have come to rely on the Folio as a mixer which adds none its own character to the track I'm working on. That cannot be said of all desks.

So how did the Powerstation fare? Well, casting it in exactly, the same role — i.e., as a mastering mixer from eight ADAT tracks down to two — I found performance to be virtually identical to the Folio which is pretty damn good in my book. Noise especially — providing a careful eye is kept on the gain controls — is considerably below anything you're entitled to expect from a mixer that is intended for live work.

Even though omitted in the manual, the frequency of the low and high EQ controls (I estimate them to be in the region of 100Hz and 12kHz) seem well enough placed to be useful as a means of controlling and shaping your sound. And the mid-range, too, is capable of homing in on the troublesome frequencies which can often cause boxiness in your sound (particularly with miked-up instruments) or boost instruments until they take on a different timbral quality.

As you may have noticed, however, with the low and high controls placed at around 100Hz and 12kHz and the mid-range adjustable only between 250 and 6kHz, a couple of quite significant holes have been left in the frequency spectrum. Frankly, I didn't find this too much of a problem, particularly with the inclusion of an insert point through which an external EQ device could be patched. But I can't think of any good reason that the mid-range couldn't have been extended to meet the borders of the low and frequency controls.

Don't get mad...

How much use the graphic equaliser will be in optimising mixer performance to take into consideration room acoustics, I'm not sure. The whole notion of compensating for room acoustics by means of graphic EQ has been discredited over the past few years — and that's using a 30-band device and a spectrum analyser. With a modest seven bands to work with, I think it's fair to say your horizons are likely to be rather limited. Look at this as multiband tone control of your overall sound and you won't go wrong; imagine it's going to optimise the sound in every venue you play, and I think you'll be disappointed.

Of much greater use in tailoring room acoustics is the onboard Lexicon processor. Using this, you should find it possible to compensate for the natural reverberant qualities of a room — or lack thereof — using reverb programs of differing room size and/or the Dark/Bright switch. You can, of course, also use it as a much more upfront device, particularly with some of the effects settings, but I think that task is better left to external processors, which of course would be freed from the task of providing an overall reverb program.

Which really only leaves the amp. I tested the Powerstation with a couple Peavey HiSys 4 cabinets I'm well used to. Any loss of detail was more than compensated for by the sheer presence of the system. This tends to be a feature of the HiSys cabinets anyway, but the Powerstation amp was certainly well up to the task of power broker. Obviously, at 700 watts RMS each, the Peaveys were well up to the job, but not being particularly noted for their efficiency, I was impressed by the sheer oomph the amp was capable of delivering, without appreciable distortion creeping in (the actual figure is <0.025% into 4 ohms). With similar, or more efficient cabinets, I'd say the Powerstation has enough power for the largest of pubs, and up to medium-sized clubs.

Conclusions

No-one who has been reading hi-tech magazines for any length of time could possibly imagine that a new mixing desk from a company like Soundcraft was going to be seriously flawed in its performance. The Soundcrafts of this world simply don't make mistakes like that. What you really have to judge is whether the facilities it provides suit your needs as a live act. Bear in mind what I said earlier about the inherent reliability of all-in-one units such as this, where each component in the chain is optimised for use with the next. Think, too, about the saving in time of only having a single pair of speaker leads to connect each time you set your PA up. But balance that against the problems that could be caused if any part of the Powerstation fails and has to be repaired: For the time this takes, you'll lose quite a large chunk of your system.

Personally, I think powered mixers are a boon, and to be recommended to anyone regularly playing small to medium-sized gigs, for whom a dozen or so channels is sufficient. The Powerstation surmounts every technical obstacle to powered mixer design, and will go a long way towards rehabilitating what was always a sound concept.