Mackie LM3204E

Paul White discovers that doubling the input capacity of a Mackie LM3204 is as simple as plugging in a single ribbon cable — and signing a cheque!

You may remember that in the March 1995 edition of Sound On Sound we reviewed Mackie's compact, 32‑channel, rackmount line mixer, the LM3204. You may even have bought one, as I did, and quickly found that on looking at the number of outputs on all your synths, samplers and drum machines, even 16 stereo input channels start to look a bit crowded. You could buy a second LM3204, but two stand‑alone mixers never really behave as one truly integrated system, which is why Mackie decided to build the LM3204E expander.

The LM3204E offers exactly the same facilities as the original LM3204, as far as the input channels and aux returns are concerned, but there's no master section, and the two mic amps on the rear panel are omitted. Instead, a slim ribbon cable connects the expander to the expansion port on the back of the LM3204, effectively doubling the number of input channels and aux returns. Aside from the mains cable, that's all that's needed, leaving a massive 32 stereo input channels, and no fewer than eight stereo effects returns.

What are the benefits of using an expander rather than two mixers? With a properly designed expander such as this, all the channels are routed to the master section of the main mixer, all the aux send busses work together, and when you solo a channel on the expander, the main mixer channels are muted, just as if they were part of the same console — which in effect they are.

Channel Facilities

For those who may not be familiar with the LM3204, the LM3204E's channels are identical, and comprise stereo line input jacks feeding a series of ganged controls. Only the first four stereo channels have insert points, but because you're dealing with line level inputs, this doesn't present a problem — you can always connect an external signal processor in‑line between the signal source and the mixer input.

Four effects send busses are provided (two mono and two stereo), but only two can be accessed at any one time. There are two knobs, switchable as a pair, to access either stereo busses 1 and 3, or mono busses 2 and 4, and switching is accomplished using the Shift button. The EQ is a 3‑band, fixed frequency arrangement, with shelving filters at 12kHz and 80Hz, and a mid‑range bandpass filter at 2.5kHz; there's no bypass switch, even though centre detent pots are used. Other than that, a stereo balance pot, a combined routing and muting button (signals not routed to the main output are routed to outputs Alt 3 and 4), and a rotary level control are provided. Two LEDs indicate signal present at ‑30dB, and impending overload — useful to see which channels are active — and as you've probably figured out already, if you are using the Alt 3 and 4 outputs to give you 4‑buss routing, then you can't use the routing buttons as mutes. Solo is fitted to every channel.

The four stereo returns are controlled via four rotary knobs, and the effect return routing is controlled from the master mixer. All the line inputs are electronically balanced on quarter‑inch jacks, while the effects returns and insert points are unbalanced.

Summary

As a mixer, the LM3204E has the same strengths and weaknesses as the original LM3204, insomuch as all mixing is done using rotary controls, there's no EQ bypass, and the EQ offers only three bands with a fixed mid. Even so, because so much can be done using MIDI level control and level automation during a mix, using knobs rather than faders for balancing isn't really a big problem. As you would expect, the sound quality is identical to that of the LM3204, which is best described as very clean and accurate, and in practice, the EQ has more than enough range for fine‑tuning keyboard sounds.

As the LM3204E is specifically designed as an expander for the LM3204, it can't be used with any other mixer, but the positive side of this limitation is that a single ribbon control offers total integration between the main mixer and its expander. I've been nagging at manufacturers for some time now to put expansion sockets on all their mixers, so that you could, for example, use an LM3204E as an expander for a Mackie 8‑buss, providing a best‑of‑both worlds setup for recording and MIDI sequencing, but as yet this hasn't materialised. Still, the future has plenty of time to happen!