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Mackie SR24•4

Mixing Console By Paul White
Published August 1995

Paul White checks over Mackie's newest mixer and predicts another round of credit card battering amongst SOS readers.

Douglas Adams once observed that alongside the development of civilisation comes a disproportionate growth in the number of shoe shops. He described how an archeological exploration of a dead planet uncovered layer upon layer of fossilised shoes, and I'm starting to feel pretty much the same way about mixers — after all, we must nearly be at the point where there are more mixers in the world than there are sound sources to plug into them! In eons to come, when our own civilisation is being rediscovered by the archeologists of the future, I can almost visualise them stumbling across the carcasses of long‑corroded mixing consoles, stacked in layers like some surreal electronic lasagne.

Seemingly undaunted by this prospect, Seattle‑based Mackie has just added another mixer to its expanding portfolio. It is a general purpose 24 into 4 desk, which somehow manages to be both compact and at the same time bristling with sensible features. Like their other mixers, Mackie's SR24:4 is incredibly solidly built. Newly designed slimline knobs have been used to keep the control surface from becoming crowded, and all the connectors are on the rear panel behind what would undoubtedly qualify as a meter bridge (if it had any meters on it).

A cursory glance at the control layout reveals that this is not specifically a recording console, as there's no monitor section. It may therefore surprise you that I believe this product will become a huge success in the 8‑track recording marketplace, as well as in the more obvious live sound and general music mixing sectors of audio.

The SR24:4 has true 4‑buss routing. Each channel can be routed to the main Left/Right outputs, or to buss pairs 1‑2 or 3‑4. By using, say, channels 1 to 8 routed to L‑R to monitor the outputs of a multitrack recorder, and channels 9 onwards to feed signals to tape via groups 1 to 4, you can easily record up to four tape tracks at a time while monitoring the results. By using the insert sends as additional direct‑to‑tape outputs, you could send signals to all eight tracks of an 8‑track recorder if you wished. To save re‑patching when using an 8‑track tape machine, eight output jacks are provided for the groups, with Group 1 feeding jack 1 and 5, Group 2 feeding jack 2 and 6, and so on.

When you come to mix, channels 9 onwards are free for use with sequenced MIDI instruments.This method of working emulates a split recording console more closely than an in‑line model, so you have full EQ on all signal paths at all times. If you tend to record by overdubbing a few parts at a time, and you don't have a MIDI system with lots of outputs, it's possible that you could even use the SR24:4 for 16‑track recording. In theory, the same is true of any conventional 4‑buss desk, so what makes the Mackie SR24:4 special?

Quick Tour

The Mackie SR24:4 combines 20 mic/line channel strips with two stereo, line‑only strips and four stereo returns, making a total of 32 different ways of getting a signal into the mixer (not counting the 2‑track inputs). All the input channel strips have six aux sends, and unlike some desks that use buss switching, each of the SR24:4's sends feeds its own dedicated buss. Sends 1 and 2 are dedicated pre‑fade sends, for foldback or cue mix applications, while Sends 3 and 4 may be switched as a pair to function in either pre‑ or post‑fade mode. Sends 5 and 6 are fixed post‑fade for use as effects sends, and each send buss has its own level control and Solo button in the master section of the console.

The mic/line channels differ from the stereo channels in that they are fitted with a 3‑band equaliser, complete with sweep mid and switchable low‑cut filter, while the stereo channels use a 4‑band, fixed‑frequency EQ system. All the mic/line channels have globally switchable phantom power, plus insert points on stereo jacks.

The routing system is quite conventional, with separate routing buttons for L‑R, 1‑2 and 3‑4, where the Pan control steers the signal between left and right, or odd and even numbered busses in the traditional way. A large channel Mute button is located below the Pan control, and all channels have the benefit of a Solo switch as well as green and red LEDs indicating ‑20dB and overload signal levels. A clever touch is the Solo/Mute status LED which blinks if a channel is solo'd, but remains on if the channel is muted.

I believe this product will become a huge success in the 8‑track recording marketplace, as well as in the more obvious live sound and general music mixing sectors of audio.

Unusual for a desk of this size is the option to select either PFL or Solo In Place (SIP) — when PFL is selected in the master section and a Solo button is pressed, the pre‑fader channel is monitored and metered in isolation, which is eminently useful in allowing you to set up the input gain trim to optimise the input level on the channel strip. In SIP mode, the isolated signal is monitored after the fader and Pan pot, so what you hear is the EQ'd signal in its proper place in the stereo soundstage, and at its correct level. More than one channel can be solo'd at a time in either solo mode, and a bright, pulsing red LED in the master section reminds you that at least one Solo button is down.

Mackie's other small mixers tend to include centre‑detented faders with plenty of extra gain above the detent position, but the SR24*4 is more conventional in that there are no detents, and the statutory 10dB of gain is provided above the 0dB (unity gain) mark, rather than the 20dB offered by some of their designs.

Master Section

The master section of this console is refreshingly uncluttered, yet nothing essential is missed out. Level controls are provided for all six auxiliary sends and four stereo returns, and to add to the routing flexibility, Aux Return 4 may be routed to either pair of groups, or to the L‑R mix. There are two further controls for sound reinforcement work which allow independently adjustable amounts of effects to be fed into the Aux 1 and Aux 2 foldback mix. A single Solo button allows all the stereo aux returns to be solo'd globally.

Each of the four Group faders may be assigned to the L‑R mix via a L‑R Assign button, and unlike many mixers which irritatingly route all odd numbered groups left and even numbered groups right, this one has a Pan pot above each Group fader, as well as a Solo button, and an intriguingly named 'Air' knob (see 'Equalisation' box).

Over on the far right is Michael Portillo — no, just kidding — a BNC connector to accept a gooseneck lamp, the stereo bargraph meters, and status LEDs for Solo and Power, but there is no status LED for the phantom power, which I find mildly alarming. The Solo Mode button is accompanied by a Level control which makes it possible to PFL a channel without having your eardrums meet in the middle of your head — a thoughtful touch; talkback is also provided. You can opt to talk into the main mix or to Aux 1 and 2, but you have to use your own mic plugged into an XLR socket on the rear panel — there's no built‑in capsule.

If a 2‑track tape machine is being used, a button lets you route this back into your headphones and the control room speakers. Another button lets you feed the tape back into the stereo mix. If you aren't careful, however, you could end up feeding the mix, via the tape machine, back into itself , resulting in a howl of feedback. This is simply nature's way of telling you that a button is down that really should be up! In the studio you'd usually route the stereo tape machine to the control room feed, but live, you might want to add backing tapes to a mix, so Mackie has given you the option to do either. A single stereo fader controls the main stereo mix level. The tape out monitor level is controlled by the master control room pot (see 'Connections' box for details).


Despite its apparent simplicity, this nicely thought out and highly versatile little desk will appeal to a wide range of users who need a compact, robust mixer that isn't going to compromise their sound. A few corners have been cut to meet the price point and to keep the size down, but none of these are disastrous. Perhaps most irritating is the lack of an EQ bypass button, and had this been a larger, more expensive console, I might also have expected to see dual sweep mids on the main channels. At this price, however, I can't really complain — six aux send busses on a console of this size is unashamed luxury, and the simple control layout means that even visiting mix engineers won't take more than a couple of minutes to figure out what is going on.

As to the sound, the 24:4 seems very much like other Mackie consoles I've used. It has a clean, well‑focused sound with no nasty, rough edges and a wide‑ranging EQ system that provides very positive control in the areas you need it most; the bottom end sounds tight and full, while the mid‑range is clear and transparent with plenty of transient detail. As a bonus, the additional Air controls turn out to be far more effective in adding top‑end clarity than you might first imagine — it's almost an 'exciter' kind of effect but without the harshness.

The review console was provided with a preliminary manual (still incredibly well written and fun to read) with most of the technical spec yet to be filled in, but practical tests indicate that this console is well up to Mackie's usual standard. Indeed, there may still be some improvements because many of the components are now surface mount, and the VLZ logo on the case announces that this is a 'Very Low Impedance Design'. If that statement applies to the mix busses, then it would imply even lower mix buss noise, which becomes more important the more input channels you have.

I don't think you need me to tell you that this little console is destined to be a big success, and its open‑ended design makes it equally suitable for live and studio work. Above all, it's almost indescribably cute!

SR24:4 Equalisation

The mic/line channels employ a 3‑band equalisation system with shelving high and low sections, plus a sweep mid covering the frequency range 100Hz to 8kHz. Many mid‑range equalisers fall down in not going low enough, but this one goes right down to the edge of the bass band, so there's plenty of scope both for fattening sounds and tuning out boxy resonances. The high equaliser operates at 12kHz, which gives a more airy sound than the 10kHz frequency chosen by some other designers, while the bass equaliser turns over at 80Hz providing plenty of control in the part of the spectrum normally inhabited by kick drums, bass guitars, and bass synths.

A 75Hz bass‑cut filter with a very steep 18dB/octave response may be switched in to reduce the effect of unwanted sub‑bass sounds on the mic/line channels.

The two stereo channels incorporate the same high and low shelving filters, but instead of one sweep mid, there are two fixed‑frequency, bandpass filters centred on 3kHz and 800Hz. All the equaliser controls have a gain range of +/‑ 15dB. There are no EQ bypass buttons but the controls are centre‑detented, making it easy to find the neutral position.

One feature I haven't seen before on a mixer of this type is the 'Air' equaliser on the four group outputs. This is a broad‑band, boost‑only, equaliser centred at 16kHz which has, as its name implies, the effect of adding top‑end clarity. With a setting of 0, no high end EQ is added, but as the control is increased, you can add up to 10dB (at least I assume they're dBs and not pounds per square inch!) of 'Air'.


Most of the connections on the 24:4 are on standard quarter‑inch jacks, with the exception of the mic inputs, the main outputs, and the mono output (all on XLRs), and the 2‑track connections which are on RCA phonos. Power is supplied directly via an IEC mains lead, not a carpet carbuncle, and the only thing that makes me a little uneasy about the back panel is that there's a small rotary gain control next to the mono output which will almost certainly become a casualty the first time someone stands the console on its back end. I know you shouldn't do this, but not everyone will be wise enough to invest in a flightcase, and with the best will in the world, mixers do occasionally get handled by roadies! Nuff said.

The Power switch is directly adjacent to the mains inlet and the Phantom Power switch sits right alongside, where it could get switched on by accident if you're used to just leaning over the console and then groping around the back panel until you encounter something that feels like a switch. Admittedly, the latter is a different size switch which you would come to recognise, but I'm still uncomfortable with this arrangement. As there's no warning LED, this could go unnoticed until there's a problem.

Jacks are provided for all the line inputs, which will happily accept balanced or unbalanced signals, and stereo TRS (Tip‑Ring‑Sleeve) jacks are used as inserts on all the mic/line channels, as well as the four groups and the main stereo output (the latter is also available on balanced XLRs). The two stereo line channels are wired so that if a signal is plugged only into the top socket, the channel works in mono. Two sets of stereo jacks are provided for phone outputs and these are located on the rear panel — not the most convenient place for the user, but far more logical for the design engineer.

The console can be used in systems operating at both ‑10dBV or +4dBu levels, due to the gain range available.


  • Excellent range of facilities for such a small console.
  • Rugged but stylish construction.
  • Clean, musical sound.


  • No EQ bypass switches.
  • No group metering.
  • No phantom power warning LED.


A neat, good sounding mixer suitable for 8‑track recording, live sound, and MIDI studio applications.