The new LM-3204 rackmount mixer from Mackie is a miracle of miniaturisation, purpose-built for the myriad stereo outputs of the MIDI-based studio. Chris Kempster negotiates Spaghetti Junction on the busses...

With keyboards, samplers and sound modules the focus of many a modern studio, a compact stereo line mixer would seem to be the ideal way of dealing with all those stereo signals. Mackie would like to think so, anyway. Their new LM-3204 packs in 16 stereo channels into a 5U 19" racking unit and, although it might look straightforward on first sight, a few quirks conspire to make it surprisingly flexible.

Channel-hopping

Those familiar with other Mackie mixers will feel instantly at home with the style and layout of the 3204. The 16 stereo input modules naturally take up the bulk of front-panel space, with a small master section tucked in at the end. A gain pot is provided for each channel instead of a fader, presumably to save on the twin evils of cost and space, and immediately above these are signal strength LEDs, one for -20dB and one for overload. It's nice having the -20dB LED, since you can quickly see on which channel a signal is active.

Above these are a solo button, and a mute switch which has a dual use. There are two extra outputs called Alt 3-4, and a signal is assigned to these when it's muted. So, in effect, you have four buses - the Main L-R outputs, and the Alt 3-4 outputs. A typical use would be to take the Alt 3-4 outputs into a multitrack, though repatching will be required to access all tracks.

The balance control will probably not see as much use as a pan pot on a normal mono-input mixer, and you'll mostly be tweaking the L-R levels on your stereo signals. However, you can input a mono signal to any of the channels, merely by using the left jack socket, and then the balance control becomes a panpot in the normal way.

"a few quirks conspire to make the LM3204 surprisingly flexible"

The three-band EQ section consists of shelving Lo and Hi EQs set at 80Hz and 12kHz, and a peaking MID EQ set at 2.5kHz. The Lo and Hi cut or boost of 15dB offers good control over the extremities of the frequency range, while the two-octave bandwidth Mid has a cut or boost of 12dB, so you can't inflict too much damage on a signal.

Four aux sends are provided, with only aux 1 and 2, or 3 and 4 selectable at one time, via the Shift button. Sends 1 and 3 are true stereo sends, while Sends 2 and 4 are mono, so effectively you have one stereo send and one mono send available at any one time. What it means, though, is that you can have four effects processors connected up permanently, with the choice of having two units at one time selectable from the aux sends.

Master section

The master section is where you'll catch your only glimpse of faders on this mixer, namely two for the Main L-R outputs, and one for the control room level. A 13-segment LED ladder shows the current state of play, and this is also ideal for setting channel levels via the Solo busses. The Solo control resides above the headphone socket and level control, which is just above the tape monitor switch. The aux return section consists of four pots as you would expect, but again Mackie have added a couple of quirks.

Using the Alt 3-4 button, the Aux return 3 inputs are disconnected, and the outputs of the Alt 3-4 buses are routed to this button instead. This means that you can use Alt 3-4 as a couple of submix buses, so that all channels that have Alt 3-4 buttons depressed go to Aux return first, before going to the main L-R busses. Another button, 'Aux return to control room only' disconnects Aux return 4, and reconnects it to the controlroom monitors and headphone socket. This is useful, since it means that you can play with effects in your cans (or monitors) without it going to the main outputs (great for awkward vocalists).

The back panel is fairly straightforward, a notable point being that there are only insert points on channels 1-4 and the the main outputs, though this isn't unduly restrictive. If there's anyone reading this thinking, 'Yes, but what if I want to record vocals', then worry not. You won't have to rush out a buy a mic pre-amp (though a nice valve model would be very tempting), since Mackie have thoughtfully provided a couple on the rear panel. With XLR sockets and phantom powering, these should prove enough for many home setups, though probably not in most live situations. The outputs are there alongside the gain controls, so you can just patch them into whichever channel you want.

Verdict

Either as a main mixer in a MIDI-based studio, or as a submixer in a live or large studio situation, the LM-3204 is a very capable unit. The basic concept is very straightforward and well-executed, but Mackie have thrown in a couple of extras which make it that much more useable. The Alt 3-4 bus, for example, which allows you to use the 3204 for tracking, and also sub-grouping when mixing, and the inclusion of two mic pre-amps which cuts the cost of having a mic preamp on every channel. A sensible compromise when many people might never use more than two anyway. In this age of stereo sources, the LM-3204 is surely going to find many a loving home.