• Alesis 1622 Mixer
  • Alesis 1622 Mixer
  • Alesis 1622 Mixer

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Alesis 1622 Mixer

Alesis are known, more than anything, for their digital signal processing expertise, yet their new mixer is an all analogue 16:2:2 design - but employing a revolutionary construction technique. Paul Ireson lends an ear.


Alesis are one of the more interesting hi-tech music companies to watch, simply because the nature of their forthcoming products is invariably harder to predict than that of any of their competitors. The reason for this is that they are led more by technology than marketing - their choices of what to make are determined not just by the identification of an obvious niche in a market, but by the availability of a new technology that Alesis can be the first to apply to music-related products. As a result of this tradition of innovation, they tend to produce surprising and rather wonderful goodies that actually cost less than they probably should. I like Alesis.

SURPRISE!



Their new 1622 mixer, or Monolithic Integrated Surface Audio Console, to give it its full and rather unwieldy title, fits pretty well into the above scheme. When Alesis first announced that a mixer would be amongst their new wave of products, many speculated that their digital signal processing expertise would be exploited to produce some kind of budget DMP7 - with loads of flashing lights, on-board effects, and MIDI sockets all over the place. This is not the case. What has emerged is a 16:2:2 mixer with not a single piece of digital electronics in sight.

What is very different about the 1622 is that it employs Monolithic Integrated Surface Construction, which enables almost all of the console's electronic components - including switch contacts, and fader and pot tracks - to be incorporated on a single circuit board. The benefits of this technique are ease of construction and reduced cost, high audio quality, and a surprising degree of ruggedness. Alesis claim that you can spill beer into the 1622 without impairing its performance, which, come to think of it, is more than can be said for most musicians (perhaps we are being made obsolete after all). Construction technique and claimed audio quality apart, the 1622 is notable for its ample provision of effects/auxiliary sends and returns: it has two pre-fader and four post-fader sends, with four mono and two stereo returns. And the price of all this? Just £699.

APPEARANCE



The mixer is wedge-shaped and can be either mounted in a 19" rack or operated as a flatbed unit. The casing is entirely plastic, apart from the metal back plane. Aesthetically, I feel the front panel is a little drab. Plastics, I'm told, can be manufactured and moulded in a myriad of diverse and wonderful colours, as well as boring ones such as grey, white, and black. Alesis have chosen grey for all 178 knobs and 20 faders, white for all 67 switches, and black for the case itself.

I'm not asking for a mixer that looks like something out of the technicolour bits of The Wizard Of Oz, but I think that a little more colour would help to distinguish knobs with different functions. The only non-participants in this monochrome colour scheme are LEDs: power and solo indicators, and stereo 15-segment bargraph meters at the top right of the panel.

The example that I had for review was actually a pre-production version, but unfortunately the minor differences between it and full production versions will not apparently extend to the colour scheme. This apart, the front panel is fine. The channels are a little close together - inevitably, given the width restrictions on rackmount gear - and I found myself adjusting pots for the wrong channel from time to time, but the controls don't feel cramped, which is important.

CONTROLS



At the top of each channel is a Trim pot, variable from -10dB to +30dB. Next is a simple two-band EQ section, two pre-fader auxiliary/effects Send pots, then four post-fader Sends. A block of slider switches is next in line governing Master Assign, Sub-Master Assign, Mute, and Solo functions. Finally, there is a channel Pan pot and 100mm throw fader. The Pan and EQ pots are centre detented for convenience. The right-hand section of the panel includes all the Master and Sub-Master controls. There are two Sub-Master channel faders, each with a Pan pot, and above these is a single Sub to Master Assign switch. There are also six auxiliary/effects Send Masters.

Returns 1 to 4 are mono, and therefore have a Return Level and a Pan pot each. Returns 5 to 8 simply have a Level control each - 5 and 7 are assigned to the left Master bus, and 6 and 8 to the right, so that 5-6 and 7-8 effectively constitute two stereo returns. Master faders are located at the bottom right of the front panel. The Monitor section controls consist of a large rotary Volume knob, a Master/Tape select switch (which allows you to select either the Master stereo bus or stereo tape inputs) and a Control Room Defeat switch. This mutes the Monitor line outputs, but not the headphone output on the rear panel. Finally, at the top right of the panel are the aforementioned bargraph meters and power and solo LEDs.

An unfortunate omission from the top panel is any form of scribble strip - there's no good reason why space couldn't have been found to place one either above or below the row of channel faders. As it is, I had to resort to the same trick that I use with my similarly-lacking Roland M240 mixer - I attached a strip of Post-It tape just below the faders. This very useful plastic tape can be written on in pencil, pen, wax pencil, correction fluid etc, and peels off easily leaving absolutely no sticky residue whatsoever, no matter how long you leave it (unlike masking tape).


CONNECTIONS



The back plane of the mixer contains all of its audio connections. The 16 channels each have unbalanced jack inputs, and channels 1-8 also have balanced XLR mic inputs and unbalanced direct jack outputs. Stereo jacks provide insert points for all 16 channels, and below this row of sockets are six auxiliary/effects sends, and eight return sockets (5-6 and 7-8 form stereo pairs, as described above). Moving on from the channels, the Sub-Master and Master busses each have two stereo sockets for inserts (eg. for patching in a stereo compressor) and two unbalanced jack outputs. Below these sockets are stereo tape inputs (via jacks) to the Monitor section, and a pair of Monitor output jacks.



"The most obvious role for a mixer of this size and spec is as a keyboard mixer. However, the flexibility afforded by all those auxiliaries, and the other routing possibilities, make the 1622 more widely applicable."


A stereo headphone socket is also provided on the back panel - a front panel location would have been more convenient (particularly when the 1622 is mounted in a rack), but presumably jack sockets aren't as easily preformed as fader tracks and switch contacts. Finally, there are two switches - one Power, and one Master Output Level selector - and a socket to take a feed from the 1622's external power supply unit

CONSTRUCTION



Any device that employs revolutionary construction is just begging to be opened up for closer examination, and the first thing that strikes you on peeking inside the 1622 is that there's something missing - like almost everything you'd expect to find! Whereas inside most mixers you'll find several circuit boards (perhaps one per input channel, plus a few more to boot) and bunches of wires snaking around, the Alesis 1622 contains just two circuit boards, which cover the whole of the underside of the front panel. They are linked to one another and the back panel by several ribbon cables.

All the faders, switches, and pots are not discrete components that are connected to the main boards - they are actually part of it, along with all but one or two elements of the audio electronics. The result is a miracle of ergonomics. If it wasn't for the necessity of sloping the case to allow a large back plane to be accommodated, I do believe the whole mixer could be redesigned to be about as thin as a paperback book!

The benefits of Monolithic Integrated Surface Construction aside, I can see that there might be some problems in incorporating fader tracks and other components that are subject to mechanical wear on the main circuit board: they'll wear out eventually, and what will happen when they do? Will the whole board have to be replaced? It won't be possible to replace a single defective or worn component, because that component will be, to all intents and purposes, the entire mixer. I dare say Alesis have borne this in mind, and have ensured that the mechanical parts of the board are suitably durable.

The most important mechanical aspect of a mixing console is the 'feel' of its faders, of course, and the feel of those on the 1622 is not that marvellous. The 100mm of travel is generous. However, the feel of the faders bears no relation to their audio performance, which is perfect - no crackles, and levels always followed the travel smoothly. Having criticised this tactile aspect of the console, I must stress that my review model was a pre-production version, and the feel of the faders is supposed to be better on the full production model - though how much so remains to be seen.

The design of the switches has also obviously been affected by the characteristics of the console's construction. They are all sliding types, rather than the pushbuttons that are almost universal on mixers - they feel fine, although the white switch tops could perhaps protrude a little further to make switching just a little easier. The rotary pots seem to be the least affected by the 1622's unconventional construction: all move freely, and have a relatively solid movement.

AUDIO QUALITY



The 1622's main selling point must be the high audio quality that its construction allows - and it certainly delivers in this respect. My initial comparative tests, conducted with a decent CD player, a stack of my favourite discs, and my ears, satisfied me that, with channels feeding straight into the Master bus, the console really is remarkably transparent. Everything from extremes of treble to low bass came through clear and undistorted. There was a slight colouration of the sound, with some material sounding just a little fragile, but far less than you would expect from a mixer of this type and size - and certainly this price. I was not able to make any objective measurements of audio performance, but subjectively it gets an emphatic thumbs-up.

Significantly, the only times when I found noise to be at all intrusive in a mix, I quickly traced the problem to a source other than any part of the 1622 - effect returns from a noisy reverb, or an unusually noisy synth for example. The main contributor to noise in a mixer tends to be its EQ section, but here again the 1622 is beautifully quiet — in fact, I soon found that I didn't own a single piece of equipment that was quiet enough to really do it justice! In all cases, the EQ would boost existing noise inherent in the source signal far more than actually adding noise of its own, which is as much as you can ask in terms of sonic purity. This two-band EQ can be described as 'effective' rather than 'sophisticated', with the cutoff points for the two shelving bands being 100Hz (bass) and 10kHz (treble). These are well chosen frequencies, allowing the most important and most obvious frequency characteristics of a source to be changed quite dramatically - kick drums can be made to really kick, and you can add a sizzling top end.

An additional swept mid-frequency band would have been welcome, to notch out awkward frequencies and enable each channel to be given the all-important tweak that can help make a great mix, but I think it is better to have quiet, simple and effective EQ than anything more complex but of lower quality. Other aspects of the console's audio performance are also excellent - crosstalk between channels is virtually imperceptible, and a hard pan is a hard pan, with no leakage into the opposite bus.



"The 1622's main selling point must be the high audio quality that its construction allows - and it certainly delivers in this respect. Everything from extremes of treble to low bass came through clear and undistorted."


SIGNAL PATH



Beginning with the channels, the input for each is passed first to the Trim control to match the channel's sensitivity to the expected levels. EQ comes first in line, after which point auxiliary/effects Sends 1 and 2 are drawn. Inserts at this point allow a channel to be processed by additional EQ, compression, limiting etc.

Channel mutes operate after Sends 1 and 2, so muting a channel will not affect a cue or effects mix using either of these busses. Solo switches are placed after mutes, so a muted channel cannot be soloed. You may have noticed that I've made no mention of channel overload LEDs - that's because there aren't any, and therefore the solo function has to be used to set correct trim levels in order to avoid distortion. If you solo a channel, its post-EQ signal is routed directly to the Monitor section in mono, and whatever else is routed to the Monitor (either the stereo Master bus or stereo tape inputs) is muted. The bargraph meters, and your ears, can now be used to set the highest trim level possible without inducing distortion.

The sound engineer's rule of thumb that a signal should just peak into the red holds good (each bargraph has seven green, four amber and four red LEDs), but there's a little room for safety on top of this before channels actually start to distort.

After attenuation by the channel faders, auxiliary/effects Sends 3-6 are drawn, and the signal for direct outputs on channels 1 to 8 taken. The channel Pan pot then determines the channel signal's position in a stereo bus which, with the Master and Sub-Master Assign switches, you can direct to either or both of the Master and Sub-Master busses.

Following the signal path for Sub-Master 1 and 2, pre-fader inserts allow additional EQ or other external processing to be patched in; given that the mixer has no EQ of any kind on the Sub busses, you might want to use additional processors to provide this facility. The two Sub-Master channels are then attenuated by faders, at which point the Sub outputs are drawn. Next, each Sub-Master channel passes through its own channel Pan pot - panning Sub-Master Channel 1 hard left and Sub-Master Channel 2 hard right effectively creates a simple stereo bus; however, as the two can be independently panned before feeding the Master bus, they can also be treated as two independent subgroups (ideal for adjusting the overall level of a group of drum sounds, for instance). Note that this panning stage is actually missed out of the manual's signal flow diagram, but it's there on the front panel, and it works.

A Sub to Master Assign switch is provided, which allows you to switch the routing of the two Sub groups to the Master stereo bus on or off - you'd turn it off either to temporarily mute the Sub bus, or in an application where the Sub outputs were somehow being used independent of the Master (eg. to provide an almost identical mix, but minus one or two channels). The Sub-Master busses join the stereo Master bus, along with the four panned mono effects returns and two stereo returns, just before the Master channel inserts, which in turn come just before the Master faders. The post-fader Master signal feeds the Master outputs, sensibly enough, and also the Monitor section input. You can select either the stereo Master bus or stereo tape inputs for the Monitor section, the latter to listen back to a recorded mix, or perhaps to monitor a mix off-tape as it goes down. When Solo is active, the bargraph meters monitor the soloed signal(s), otherwise levels in the stereo Master bus are displayed.

APPLICATIONS



The most obvious role for a mixer of this size and spec is as a keyboard mixer - high sonic integrity, loads of effects sends/returns, and a rack-mountable design. Perfect. However, the flexibility afforded by all those auxiliaries, and the other routing possibilities, make the 1622 more widely applicable.

In the manual, Alesis are rather keen on the idea of using it in a 4-track or 8-track recording system, where the eight direct outs (channels 1-8) feed the tape recorder inputs, and the tape outputs are connected to mixer channel inputs 9 through 16. This is quite feasible, of course, and for some people six auxiliaries and excellent audio quality might compensate for the overall lack of flexibility in comparison with a full 8-bus console, but I can't really see many home recording purists going for this. Even with the addition of a patchbay, a 16:2:2 configuration is really not ideal for multitracking. Sound reinforcement is a more likely bet - eight balanced mic inputs, enough auxiliaries to set up plentiful cue mixes and still use several effects loops, and it's beer-proof!

The most interesting area of application, however, could be in a variety of supporting roles in professional studios and perhaps audiovisual post-production suites. The 1622's audio quality is good enough, it has routing flexibility in its favour, and at this price it's hardly a major purchase. It could therefore find itself more or less falling into some surprising little niches.



"Alesis claim that you can spill beer into the 1622 without impairing its performance, which, come to think of it, is more than can be said for most musicians..."


It remains to be seen whether this turns out to be the case or not, but above all else, the Alesis 1622 will undoubtedly find a happy home in the small computer-based studios of the MIDI age. As the quality of our instruments and outboard equipment has improved, so the quality of affordable small mixers has had to improve. Also, as outboard equipment has dropped in price and recording on 'virtual' tracks has become the order of the day, more input channels and effects are required simultaneously, even in a small setup. The Alesis 1622 mixer is thus perfectly in tune with the audio requirements of today's MIDI studios in offering uncompromising quality and plenty of auxiliaries. It is lacking in some minor respects - visual appeal, channel overload LEDs, and a scribble strip - but on balance the console's strengths outweigh these trivial weaknesses. It may not have the look, but it has the sound - almost certainly better quality than you need, for less money than you thought possible.

FURTHER INFORMATION

£699 inc VAT.

Sound Technology plc, (Contact Details).

ALESIS 1622 MIXER

Frequency response: +0/-2dBV 20-20kHz.
Harmonic distortion: Better than 0.015% @1kHz @0dBV.
Crosstalk: -91 dBV. Channel to Channel @1kHz @0dBV.
Signal-to-Noise ratio: Worst case -78dBV Master or Monitor with 16 inputs @ unity gain.
Input gain: +56dB Mic input to Master Output.
Max input level: +17dBV.
Input impedance: 3Kohms Mic; 1 Mohm Line.
Max output level: +17dBV.
Output impedance: 500 Ohms (all outputs).
Meters: two 15-segment LEDs (VU response).
Connections: 8 Mic inputs (XLR); all others ¼" jacks.
Level: Main Outputs switchable +4/-10dBV operation.
Power: External 9V PSU (supplied).
Size: 19" x 21" x 1.5-6".
Weight: 14lbs.


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Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

 

Sound On Sound - Mar 1990

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Review by Paul Ireson

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