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Soundtech ST1602

Quantum Mix Compact Mixer By Mike Crofts
Published January 1998

Soundtech ST1602

We all know there are lots of compact mixers on the market — but then lots of people need a compact mixer, and SoundTech's 16‑channel Quantum Mix is priced for mass appeal. Mike Crofts looks before he leaps.

The range of audio products in the SoundTech range seems to be expanding almost as fast as my waistline these days, and the ST1602 Quantum Mix is one of their latest offerings aimed at those — like myself — who are involved in live sound and/or home and location recording projects. As with all SoundTech gear, this mixer is available only from Smart Sound Direct, who will, I believe, let you have a 10‑day home trial so that you can be sure that what you've bought is what you really really want.

The ST1602 is a 16‑input, 2 + 2‑output compact mixer with a fairly standard complement of eight mono microphone/line channels and four stereo line‑input channels. Outputs are main left and right, with an additional 'B‑mix' stereo output which is available either as an alternative signal route or as a submix. There are three auxiliary sends, a control room output, and an array of other patching, routing and access features; at first sight this desk appears to pack an awful lot of goodies into its very compact frame.

First Impressions

The ST1602 is one of those mixers which takes you aback when you open the box and discover how small it really is. This is a compliment, as all the features you would normally expect are there, plus a fair few you normally wouldn't, and all the main controls and access points are available from the top panel.

As with every other product I've seen from this company, the mixer is finished in black, which gives it a discreet and businesslike appearance. There's quite a bit of information printed on the main control panel, and this makes operating the desk a piece of cake; the functional legends are in white, and there are helpful reminders in green. SoundTech have also gone to considerable trouble to assist the user in other ways, such as providing detented rotary controls not only for the EQ section but also for the aux sends, which makes a starting setup very easy to achieve if it suits your particular way of working.

Let's Get Technical

At the risk of incurring the wrath of all the technical anoraks out there, I'd like to avoid a lengthy regurgitation of the facts and figures contained in the manual, and content myself with saying that this mixer is very well specified in all the usual ways; it has excellent response and noise figures, and I didn't come across anything which leads me to doubt its claimed technical performance for a moment. I was very much more interested in actually getting my sticky little fingers all over it, to find out what it does and how well. First, though, it's worth running through the ST1602's feature list.

The first eight inputs are mono channels, and are equipped with those handy dual connectors which will accept both (balanced) XLR and jack plugs. For my money, this is an excellent way of saving space on the panel, and the sockets themselves seem to be rigid and sturdy when used with both types of plug. An insert point is provided by means of a TRS socket just below the input connector. There's a gain/trim control which is marked at the unity point on the line input trim scale — again, a good starting point.

Equalisation on these mono channels is 3‑band with a swept mid, a facility not by any means to be taken for granted on a mixer in this class. A low‑cut filter is also provided for each channel, and when it's selected this introduces a steep (18dB per octave) attenuation below 75Hz, for cleaning up muddy signals, or eliminating unwanted stage noise, for example. I found the EQ worked very well and the swept mid section was especially useful when dealing with vocal parts.

The four stereo channels are somewhat simpler, in that they have twin input jacks which can receive either balanced or unbalanced feeds, and a sensitivity switch instead of the gain/trim pot. EQ is still 3‑band, but here the mid control is a 2.5kHz peaking circuit with 12dB of cut or boost.

The three auxiliary sends, common to all channels, are designated as Monitor, Mon/Efx1, and Efx2. Each channel control is marked with a scale from 0 to 10, and the pots are centre detented; this is useful if you make much use of the sends, as it provides a good starting point from which to make finer adjustments. Use of these controls quickly becomes a matter of instinct, and the detent point helps you know roughly where each is set without looking at it.

In addition to the usual pots and pans at the foot of each channel strip, there is a button which will interrupt the signal path and feed it to the 'B mix' master buss, which is, in effect, a second pair of main outputs, controlled via a stereo fader just to the left of the main left/right faders. If used independently of the main mix, this facility could be pressed into service for theatre sound, where a different mix is required to be fed to different parts of the house, or for direct‑to‑4‑track recording, if the tape tracks were fed main left, main right, B‑mix left and B‑mix right. The entire 'B' mix can also be routed as a submix back into the main mix, and/or sent to the control room outputs.

The master section is pretty much as you would expect, but it does include a meaty selection of monitoring options, routing and submixing facilities which should be enough to keep anyone happy. The 3‑colour LED meters are clear and bright, and can be used to monitor various signal points; there is even a level set function associated with the PFL button for solo channel adjustment.

The main outputs are on both balanced XLRs and unbalanced jacks, and there is a rear‑panel switch which changes the output from line (+4dBm) to a lower 'mic' level — another small feature underlining the thought which has obviously gone into designing this mixer to be as versatile as possible.

Phantom power is available on all eight mono channels, and is globally switched from the rear panel, with an LED indicator on the front panel to indicate when it is active. Next to the stereo auxiliary returns are two sets of RCA sockets for tape in and tape out, although there is no dedicated tape input level control to feed directly into the main mix — it just goes in at whatever level the tape input receives, or it can be controlled by routing it through the Control Room buss.

Power is supplied via a standard IEC mains lead, thank goodness — no wall wart to worry about, tread on or leave at home!

Testing Times

As the ST1602 is aimed at both live sound and recording work, I tried it on a bit of both; the results were all I'd hoped for, and were obtained without the benefit of having much time to get acquainted with the desk beforehand.

As I had promised to make a rough 'songs demo' tape for an acoustic band, I used the ST1602 as the heart of the operation, along with a fairly standard 4‑track tape and stereo master setup. The recorder didn't have balanced inputs, so the mixer was an essential part of the process even before I explored its mixdown and monitoring capabilities.

Before starting on the recording proper, I turned all the channel inputs up full, and whacked up the master output into the monitors, just to see how much real‑world noise there was. In the context of recording decent signals at sensible levels (ie. without having to use excessive amounts of input gain) the noise was hardly noticeable, even with all channels open. With a signal present, the mixer made no discernible noise contribution to the end result, and I would be more than happy to use it for digital recording or mastering.

The EQ was consistent and docile in use, and the swept mid was a real godsend when balancing between male and female vocal lines. I left the HF and LF more or less flat and swept in around 2dB of mid cut until everyone liked what they heard. The low‑cut filters were left switched in on all channels.

The results were very pleasing, and the desk was good to work with. I found it a bit disconcerting at first to have three master faders feeding four recorder channels, but this made no practical difference to this session. I used the desk to mix down to a stereo master tape, and again its low noise and friendly EQ was appreciated.

About the only problem I encountered was with the metering and B‑mix routing switches, which are black (like the panel from which they protrude). It's not all that easy to see whether they are in or out, especially if you're directly above the desk. A colour band around the button would help here, and at minimal production cost.

Suggestions Box

I have hardly anything to say here, except that I would have found a dedicated level control for the tape inputs very useful, and a pair of mono faders for the B‑mix would definitely qualify this as a 16:4 mixer — as well as making it look more symmetrical to an old control freak like me. Oh, and the manual (admittedly comprehensive and clear) could be a bit more interesting, with maybe a few suggested recording/mixdown configurations, because when you get one of these for Christmas you know you won't be allowed to play with it until after dinner, so you'll have to make do with reading the manual all morning, and then in bed for a few nights, and in the bath (where of course you must never, ever use your actual mixer) and so on...

Summing Up

This is a highly practical and versatile little mixer, which is ideal for live and home recording, and for smaller live PA work too. The ST1602 manages to squeeze just about everything you could want into a compact and well‑engineered package and, with these features and figures, is worthy of a trial anytime.

Down The Pub

At a band rehearsal and subsequent live gig, I used the ST1602 as the sole mixer, since the venue wasn't large enough to warrant kit mics or anything extravagant like that. In the dark, smoky and generally doubtful environment which passes for a pub gig these days, the ST1602 was fine, if a little small — I got a few cables plugged in early on so that I could find my way back to it if we became separated in the smog. It was easy to achieve the sound balance I was after, and the swept mid EQ once again came in handy.

The monitor send is a bit of a sparkler on this desk, as you can feed in the other two auxiliary busses; I used this to submix the foldback balance between two basic settings when the band were using different instruments and wanted a different monitor mix — all without having to alter any of the channel settings themselves.

Solid As A Rock

One of the things I like most about this little mixer is its solid feel. It weighs only 5.5kg, yet it's sturdily constructed and has decent rubber feet which stop it sliding around. It even comes apart fairly easily (I know this because I had a look inside, and can report that all seems well put together and should survive the odd bit of rough handling.)

Ergonomically speaking, the slimline knobs used on all the rotary controls leave enough space to accommodate the average finger, and the faders, although not roller‑ball smooth, are perfectly well‑behaved, though I found them better when pushed or pulled from the outside of the knob rather than using the finger trough.

At the end of a gig or hard rehearsal, no‑one really wants to start heaving gear around. As a change from my usual live desk, which really needs two people to move it (and that usually means me and, well, me) packing up the ST1602 is a bit like not forgetting your handbag. As with all mixers of this type, the controls stick up proud of the top panel, and if used on the road this desk would need the protection of a small flightcase, which at this size shouldn't set you back many quid.


  • Well specified.
  • Very versatile design.
  • Good build quality.
  • Excellent performance.


  • No dedicated tape level control.
  • Twin B‑mix faders would increase flexibility.


A well‑specified, neat and flexible tool for recording and live sound work.