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TC Electronic M300

Dual Multi-effects Processor
By Hugh Robjohns

Heavyweight TC effects processing but with a menu-free, easy-to-use, hands-on interface.

Digital multi-effects have come a long way since the earliest designs hit the streets in the late '80s — remember the classic Yamaha SPX90? Since those days, TC Electronic have gradually gained in market-share to become recognised as one of the leaders in the field of multi-effects processing and artificial reverberation. The company's new M300 dual multi-effects processor is an incredibly compact, easy-to-use unit which provides a broad range of effects and reverbs in an attractively priced package. Quality, though, is certainly not compromised, as a quick scan of the specifications will attest.

Mechanics & Interfaces

TC ELECTRONIC M300 multi-effects.Photo: Mike CameronThe M300 is encased in a very shallow 1U rackmount box, measuring just 100mm behind the rack ears. The steel case is painted black, with a silver-grey front panel littered with knobs — an unusual feature on a digital multi-effects box these days. However, before addressing the front-panel controls, let's start this tour in the customary fashion, by taking a look around the back.

The rear panel carries the ubiquitous IEC mains inlet which feeds a universal switched-mode power supply, accepting mains supplies from 100 to 240 Volts. There is no power switch either on the rear or front panels, which is a disappointment.

There are two inputs and two outputs, all on quarter-inch TRS jack sockets able to accommodate both balanced and unbalanced signals anywhere between professional and semi-pro line levels. The A-D and D-A converters are all 24-bit, 128x delta-sigma oversampling types, producing a complete analogue-analogue converter delay of about 1.5ms. A switch near the input sockets selects the channel processing configuration — of which more later — and the left input is normalled across to the right to allow single-input working.

The machine is also equipped with 24-bit digital S/PDIF phono connectors to provide digital interfacing at either 44.1 or 48kHz. The analogue and digital outputs operate simultaneously so the unit can be used as a high-quality A-D converter if required, although the internal sample rate is fixed at 44.1kHz when analogue inputs are selected. A pair of MIDI sockets are provided for the usual remote control and preset data dumping facilities, and a footswitch socket is wired to allow a bypass function through the tip connection plus a tap tempo facility through the ring connection.

The internal signal processing structure of the M300 follows TC Electronic's usual arrangement, with both serial and parallel processing configurations, feeding a shared stereo output. However, the two engines serve distinct, fixed functions: engine one provides a range of multi-effects algorithms while engine two provides only reverberation algorithms.

There are two available routing configurations: serial or dual send/return. The serial mode places the multi-effects processor engine before the reverberation processor, without any facility to change the order — so no phased reverbs. This isn't really a limitation for 99 percent of applications, but worth pointing out. The latter mode, indicated by a green LED on the front panel, configures the M300 as two independent processors. The left input feeds the multi-effects processor, while the right input feeds the reverb processor, the outputs of both stereo effects being summed to a common stereo output. If only the left input is connected, this signal is normalled through to the reverb processor as well, providing a mono-in, stereo-out dual-effect unit.

These routing arrangements allow the M300 to be used as a composite effects machine, either directly in line (or in an effects loop) for a single mono or stereo source — voice, guitar, keyboard or whatever. Alternatively, it can serve as a convenient one-box, dual-effects processor running off a pair of mixer aux-sends.

Hands-on Control

The majority of multi-effects units employ the familiar paradigm of LCD display, navigation buttons, and a menu-driven interface. Whilst being supremely flexible, this common arrangement could hardly be described as user-friendly — particularly when standing on a stage in the spotlight and needing to change some parameter quickly.

However, TC Electronic have chosen to equip the M300 with a simple and extremely intuitive collection of knobs and rotary switches. There is no LCD, no menu, and the only numeric display is to access the 99 user presets. This is the perfect machine for the technophobe who wants the effects but not the hassle.

The input section comprises a level control (±12dB), a wet/dry Mix control, and an Effect Balance control (ie. the relative output level of the effects and reverb processing). The input signal level is displayed, albeit crudely on a pair of tricolour LEDs, illuminating green above -40dB, yellow at a nominal operating level, and red near clipping. If this sounds vague, it's because it is... but I had no problems in setting an appropriate level in practice. Having said that, the (digital) gain control has a strange action, with a noticeable delay between turning the knob and hearing a level change!

A pair of front-panel buttons select the digital input, and activate Bypass — both functions have associated LEDs so that the status of the machine is always clear. If digital input is selected but the signal is absent or incompatible, the LED flashes and, after a brief delay, the unit reverts to its analogue inputs. If a suitable digital input is applied subsequently the machine will automatically reselect the digital input.

In the serial configuration the bypass function operates exactly as you would expect, passing the input directly to the output. However, in the dual send/return mode it acts as an output mute instead — these two modes being suitable for the most likely applications. The final LED in this section illuminates when the dual-send/return configuration is selected, as already mentioned.

The Multi-effects Engine

The next section controls the multi-effects engine and comprises a large rotary switch to select the processing algorithm, followed by two further rotary controls. The effects on offer are six delays (dynamic delay, studio delay, tape delay, delay, ping pong, and slap back), vintage and standard phasers, hard and soft tremolos, two flangers, chorus, a compressor, a de-esser, and an Off position. For the delay algorithms, where timing is critical, a tap-tempo facility is available either through a front-panel button or via the rear-panel footswitch socket, and a yellow LED flashes to indicate the current timing. A three-LED bar-graph meter scaled -3, -6 and -12dB shows the amount of gain reduction provided by the two dynamics processes.

You can switch the M300's routing configuration between serial and parallel using a small switch on its rear panel. Unusually for a unit at this price point, the M300 offers balanced analogue I/O, plus S/PDIF digital connections and an internal switched-mode power supply instead of the expected 'wall-wart'.You can switch the M300's routing configuration between serial and parallel using a small switch on its rear panel. Unusually for a unit at this price point, the M300 offers balanced analogue I/O, plus S/PDIF digital connections and an internal switched-mode power supply instead of the expected 'wall-wart'.

The two rotary controls are multi-functional, in that their specific functions change to suit the selected algorithm. Their main labels are Timing and Feedback/Depth, with subtitles of Amount/Drive and Frequency/Ratio respectively. The Timing knob acts as a multiplier for the delay algorithms, modifying the delay time across a range of 0.5 to 2. For the chorus, flanger, phaser and tremolo functions the control adjusts the modulation rate and, although no specific values are given, it always seemed to span a suitable range for the selected effect. For the de-esser algorithm this control adjusts the amount of de-essing, while for the compressor it sets the amount of drive (determining how far the input signal exceeds the threshold). The Feedback/Depth knob adjusts the amount of feedback for all the delay algorithms, and the depth of effect in the chorus, flanger, phaser and tremolo algorithms. It also adjusts the frequency selection of the de-esser and the ratio of the compressor.

The Dynamic Delay algorithm warrants further comment, as it is a very handy effect first seen on TC's highly regarded 2290 processor. The level of the repeats is kept low when the input signal is high, but is then allowed to increase when the input level is low. This is a surprisingly effective system which ensures that the repeats do not clutter up the main sound, and it is entirely automatic, making it ideal for live performances.

The Vintage Phaser employs four all-pass filters for a strong, obvious effect, whereas the standard version uses twelve filters for a much smoother, more subtle process. Similarly, the Flanger II setting is much more intense than the Flanger I setting.

The Reverb Engine

The controls for the reverb engine are arranged in a similar way to those for the multi-effects, with a large rotary switch and three rotary controls. The switch selects the basic reverb algorithms, the collection consisting of: concert and 'TC Classic' halls; vocal hall, room and studio; large cathedral; drum room and box; ambience; live reverb, spring; two plates; club; living room; and an Off position.

Concert Hall is more diffuse than the TC Classic Hall, and Large Cathedral has stronger early reflections. The three vocal settings simulate soft, wooden-sounding rooms designed specifically to complement singing voices, whereas the drum programs are harder-sounding for percussive instruments. The live reverb is a bright, grainy, relatively crude reverb algorithm which is intended specifically for PA applications and has been designed to cut through where more sophisticated algorithms tend to disappear.

The rotary controls are labelled Pre-delay, Decay, and Color, their ranges changing to suit each algorithm in an entirely intuitive and logical way — the Color control changes the brightness and diffusion character of the reverb. The default positions for these controls, as with most of the others on the machine, is at 12 o'clock. Although the range of algorithms may appear limited, there are clear differences between each, and the three rotary controls enable a great deal of fine tuning.

Although the processing engine and algorithms employed may not reach the lofty standards of TC's high-end units, they are still of extremely good quality and are very usable in context. The smaller rooms actually work quite well, and the bigger reverbs sound smooth and spacious.

Scrolling Through The Presets

The final section of the user interface is concerned with the saving and recalling of user presets. There are no factory presets in the conventional form, although since the multi-effects and reverb processors each offer 16 variations, you could view the machine as being shipped with 256 factory presets.

Recalling a user preset is done in a rather clever but simple way using just four buttons, a two-digit seven-segment display, and a row of small LEDs. An unusual aspect of the M300 is that it can be used in a purely manual mode with the preset facilities switched off completely, in which case the numeric display shows only a pair of dashes. Pressing the Preset button to the left of the display toggles the preset functions on or off, and when turned on, the last used preset number will flash, meaning it is available but not yet active. Alternative presets from 01 to 99 can be located by using the up and down arrows on the opposite side of the display (sensibly, scrolling down from 01 loops around to 99). The desired preset is then recalled by pressing the Load button, at which point the numbers become steady.

A row of nine small red LEDs located above the numeric display illuminate if the corresponding control is set differently to the recalled parameter, but remain unlit if the setting is the same. These LEDs are grouped to reflect the three operational sections of the machine and the various controls within them. The first two LEDs represent the Mix and Effect Balance controls in the I/O section, the next three reflect the Algorithm, Timing and Feedback/Depth controls of the multi-effects section, and the last four indicate the Algorithm, Pre-delay, Decay, and Color controls of the Reverb section.

Should you want to adjust a particular parameter within a selected preset, all you have to do is rotate the required control through the pre-programmed position. At this point the corresponding LED will extinguish and the parameter will become 'live', responding to manual adjustment. If you then want to save the newly modified effect, all that is required is to press and hold the Load button for about three seconds. If restoring the effect in its original preset position the display will flash briefly to indicate the action. Alternatively, a different location can be selected by using the up or down arrows — pressing and holding the Load button will then cause the flashing display to become steady when the data has been stored. This is a very elegant system which is extremely quick and intuitive to use and, more importantly, allows easy updating and adjustment of effects parameters on stage or during a live production without having to navigate through a host of menus.

The Preset On/Off button is also used to configure the machine's MIDI facilities. By pressing and holding this button the current MIDI channel is displayed (Omni by default, but any specific channel can be specified, or none.) The handbook includes a complete catalogue of MIDI functionality, but the essentials are that MIDI Program Change messages will change preset numbers, controller changes will alter program parameters (including input level, bypass, and digital input selection), and MIDI timecode can be used to set delay tempos. With the exception of MIDI Time Code, all this information is also transmitted from the machine over MIDI channel 1, by default.

The M300 In Action

The M300 is a really nice unit with a useful range of good-quality effects and pragmatic flexibility, but its key strength is its immediacy. TC Electronic have managed to invent a user interface that does exactly what you want without you having to squint at nested menus on LCD screens.

For the stage musician, live sound engineer, or theatre sound balancer the M300 is a godsend, providing no-fuss, immediate control of every effect parameter, with a good range of decent effects and reverbs. The inclusion of a simple preset facility adds to the functionality and ease of use in choreographed performances, yet retains the facility to simply reach out and change a parameter if required.

For the recording musician or studio engineer, the pure immediacy of control will, in many cases, outweigh the relative lack of adjustable parameters. After all, who really tweaks all the variables in most multi-effects unit's algorithms? TC Electronic have provided the most important and significant parameters on knobs, and everything else is preset within the algorithm to provide a good, 'usable straight from the box' sound.

I recently acquired an M*One XL to serve as a general-purpose second reverb and multi-effects unit in my own studio, so impressed was I with its performance during a recent review. It inevitably formed a basis for comparison with the M300, despite the latter retailing at almost half the UK price. I found the multi-effects algorithms were virtually identical at their default settings, and although the M*One provides a wealth of adjustable parameters, the M300 compensates with a wider variety of preset starting points. For example, the M*One doesn't have a 'Tape Delay' algorithm, but it is easy to create the effect with careful manipulation of high cut, delay, and feedback parameters. The Dynamic Delay functionality is completely absent from the M*One though, and this is definitely a feather in the cap of the M300. Comparing reverb algorithms created a similar impression of near equality, although I think the M*One was the smoother and more detailed of the two by a small margin. Once again, the lack of adjustable parameters was more than compensated for by a greater number of starting presets in the M300.

The bottom line is that this is an extremely competent, well-designed machine, packing a lot of professional features, I/O flexibility, and excellent sound quality into a really compact, easy-to-use, effects processor. It is ideal for any kind of live sound application where immediate controllability is essential. It would also serve as a great first step on the ladder for a home studio novice, and is unlikely ever to be outgrown. As a second, general-purpose multi-effects and reverb unit, it would be hard to find a more cost-effective machine, and its operational immediacy makes it really fun to use and to experiment with creatively. Highly recommended.


  • Professional specifications throughout.
  • Digital and analogue I/O.
  • Flexible processing configurations.
  • Internal PSU.
  • Good-quality, highly usable effects algorithms.


  • No power switch.


A multi-effects processor with a neat user interface which gives it analogue-style intuitiveness. A versatile range of effects and reverbs provide professional performance at a budget price.


M300 £249 including VAT.

TC Electronic UK +44 (0)800 917 8926.

Published June 2002