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TC Electronic M One

Dual-Channel Effects processor By Hugh Robjohns
Published February 2000

TC Electronic M One

TC Electronic have an enviable reputation for their high‑quality digital effects processors, and have now launched the first of a new line of budget‑conscious units. Hugh Robjohns checks out the M*One.

The M*One is a new addition to TC Electronic's product line which combines state‑of‑the‑art reverbs and essential modulation effects in a very affordable 1U rackmounting package. The M*One is aimed principally at the budget‑conscious studio or live‑sound rig, and so foregoes some of the professional interfacing facilities that might be found on a more upmarket unit like TC's M2000, for example. Nevertheless, the machine still boasts balanced analogue inputs and outputs and 24‑bit S/PDIF digital I/O.

The machine has a dual‑engine topology with considerable flexibility in the way the two processors can be configured. For example, as well as operating as a true‑stereo unit with the engines performing identical tasks on the left and right channels, there is also a dual‑mono mode, a dual‑mono send mode with common stereo return, a separate parallel‑processing mode with commoned stereo I/O, and a separate series processing mode, also with a stereo I/O (see the Configurations box).

Although the M*One is geared mainly towards providing reverberation effects, a number of alternative processing algorithms are also available. These include the usual delay‑related effects such as delays, chorus, phasing, flanging, tremolo, pitch‑shifting and de‑tuning, as well as parametric equalisation and a range of dynamics tools. The machine is supplied with 100 factory presets and has memory for a further 100 user settings.

Technical Tour

TC Electronic M One

TC's new machine employs 128‑times oversampling 24‑bit A‑D and D‑A converters, with 24‑bit digital I/O via the S/PDIF interface. The user manual states that the internal processing is also performed to 24‑bit resolution, which seems to imply a lack of DSP headroom — mix two 24‑bit signals together and the result is rather bigger than 24 bits! The analogue and digital input attenuators are, therefore, an essential tool in avoiding internal overloads. Specifications are generally to a high standard, with a quoted distortion figure of better than 0.0025 percent and a dynamic range of greater than 100dB from the analogue I/O.

The M*One is simple to interface, although being a 'budget model' there isn't an XLR in sight. The rear panel carries the common IEC mains inlet, accepting any voltage between 100 and 240V, while a tip‑sleeve quarter‑inch socket allows connection of a momentary‑contact pedal switch. This may be assigned to bypass either or both of the processing engines, or to act as the tap‑tempo input. The familiar three MIDI sockets are also presented for remote MIDI parameter control, data dumps and program changes.

The digital I/O is provided on a pair of phono sockets, with four TRS quarter‑inch sockets catering for the dual‑channel analogue inputs and outputs. These connectors accept both balanced and unbalanced connections, and the left input is normalled to both channels when nothing is plugged into the right input socket.

The front panel is well laid out, although it suffers a little by being very black! The operational controls are grouped into five separate sections with a large "multispectral LCD display" panel just left of centre. This is a combination unit with provision for 280 separate icons and images in the main section, plus a row of 23 alphanumeric characters along the bottom.

The left‑hand side of the front panel carries a power button and three conventional rotary controls providing adjustment for the input level, dry/wet mix, and the relative output level balance between Engines 1 and 2. The LCD panel provides vertical bargraph input‑level meters covering a 40dB range, along with a graphical display showing input source, sample rate, and engine topology. There are also gain‑reduction bargraph meters and a table of algorithm indicators for each engine.

The right‑hand side of the display shows the factory or user preset number, and carries indicators to show when a preset has been edited and when MIDI data is being received. The text line below the main part of the display provides the name of the algorithm and identifies the various parameters and their settings during editing.

The right‑hand side of the machine is mainly taken up with push buttons, all of which have LEDs in the top corner to show when their particular function is active. A rotary encoder allows selected parameters to be adjusted, although winding in high values is a little tedious.

The first group of four buttons is related to the machine's setup, with buttons labelled Routing, I/O, Tap, and Utility — all fairly intuitive stuff! The next group of four controls the effects: Algo/Edit 1 and 2 access the algorithm editing for each engine, and the functionality of Bypass 1 and 2 can be determined in the I/O setup mode (see box). A third grouping of buttons, labelled Program, offers the familiar Store and Recall buttons to access and save memory presets, whilst the final group provides cursor up/down buttons to navigate the menu options, the data control wheel, and the Enter and Exit buttons to confirm or cancel an action.

Setup Options

When activated, the I/O Setup menu parameters are displayed in a text line at the bottom of the LCD. Initially, this indicates the current input selection (analogue or digital), the alternative being selected with the rotary encoder. Cursor keys allow the other options in the menu to be selected, the next being the sample rate — internal 44.1, 48kHz, or the rate of the signal presented at the digital input — followed by the analogue output level. This can be set at +2, +8, +14 or +20dBu. A further option attenuates both the analogue and digital output level by up to 100dB in 1dB increments, while the gain of the digital input can be adjusted from +6 to ‑100dB. The digital output can also have dither applied when truncating the standard 24‑bit output down to 20, 16, or 8 bits.

The Utility menu contains facilities to select preset banks (user, factory or external), set a receive MIDI channel, and enable reception of data from continuous controllers. MIDI bulk dumps can also be controlled from here, and the SysEx ID can be set to enable the machine to respond to appropriate external MIDI commands. Another useful facility is a 'Routing Lock' preventing the current engine configuration changing when new presets are recalled. The measurement unit for the tap tempo display (mS or BPM) can be selected from this menu, and pressing the Tap button allows further tap tempo functions to be accessed — such as to which engine the timing data applies, and the tap subdivision (17 options from 1 to 1/32T).

There are three bypass modes in the Utility sub‑menu: Dry (conventional processor bypass), FX‑In, and FX‑Out — the last two muting the input or output, respectively, of the processors. The footpedal input can be set up to operate the tap tempo facility or to bypass either Engine 1 or Engine 2. Finally, the viewing angle of the LCD panel can be adjusted over a wide range.

Like most TC Electronic equipment, the M*One is very intuitive to set up and operate. I found little need to consult the user's manual, although this is well produced with clear, concise information on every aspect of the machine and its effects algorithms. For the impatient user there is also a Quick Guide to the M*One, which covers the bare essentials in just three pages!

In Use

The M*One is a great effects processor — easy to set up, fast and flexible to use, and good value for money in terms of the quality of reverbs and effects. The reverb algorithms may not have the sophistication of TC's latest VSS‑based ones (as found on the M3000, for example), but the results are all very usable. I found the ability to alter the relative level between early reflections and main reverb tail particularly powerful in creating believable auditory illusions of physical spaces.

The other algorithms are, in the main, well engineered and useful, the only weak link being, inevitably, the pitch‑shifter. Delays, chorus, flanging and phasing work extremely well with useful variations, the equaliser is powerful, and the dynamics algorithms allowed accurate and reliable control of programme levels. The provision of the gain‑reduction metering on the front panel helped considerably in setting up and maintaining the dynamics processes too!

Overall, I found the M*One to be a highly cost‑effective processor with typical TC Electronic operational intuitiveness, a good range of quality reverbs and effects, extremely flexible configuration options, and comprehensive interfacing. Definitely one to check out if you are looking for a new multi‑effects machine.

M*One Versus MPX500

Lexicon's MPX500 is directly comparable to the TC M*One in terms of costs and broad functionality, and Paul White has reviewed it elsewhere in this issue of SOS (see page 182). Although we don't normally do head‑to‑head reviews, the opportunity arose to put these two machines side by side and compare them objectively.

Both are simple to use and their algorithms are easy to edit, although the very different operating styles of the two machines will tend to make them appeal to different people. The technical performance of both is essentially the same, although the dual‑engine configuration of the M‑One makes that a slightly more flexible general‑purpose machine.

The Hall, Plate and Room reverberations from each machine were of very similar calibre, with only subtle nuances to choose between them. The Lex sounded a little warmer and fuller on some programs, whereas the TC sounded better on others. There was really very little to choose between them until we compared their simulation of small acoustic spaces. Here, however, there was no doubt: the Lexicon algorithms seemed the most realistic. We also compared both machines with the Lexicon PCM90, and it was easy to see why the PCM90 costs rather more — but then, you wouldn't expect to get a TC M3000 at the price of either the M*One or the MPX500 either.


The M*One's processing engines offer a lot of flexibility in their configuration, via the 'Routing' menu. The first option is the Dual Send/Return mode in which the two engines remain entirely separate, Engine 1 receiving the left input and Engine 2 the right. Both engines generate stereo outputs which are combined (via the Effect Balance control) and presented as a composite output mix. This configuration allows two separate mono effects sends from the console to be processed independently and returned via a single stereo return.

The next option keeps the two engines separate, but has them processing the same input signal in parallel, the left and right inputs being summed to mono before being passed to both engines. The stereo outputs from the processors are combined as before. This mode applies two independent but simultaneous effects.

The Parallel/Serial mode is structurally similar to the Dual S/R mode described above, but with the addition of a feedback path between the output of Engine 1 and the input to Engine 2. The left input feeds Engine 1, the right Engine 2 and the amount of feedback ('crossfeed') is set in the routing menu (and stored in the preset). This mode would, for example, allow reverberation in Engine 2 to be added to repeat delays from Engine 1.

The Serial mode seems positively simple in comparison. Engine 1 processes the stereo input and Engine 2 works on the stereo output of Engine 1. The output of each engine can also be combined with a percentage of its input signal, if required. This configuration enables complex processes to be created where one function must be performed prior to another (for example, de‑essing before a very lively reverb).

The next option is a 'Stereo Linked' mode, where each engine processes only its own input channel and outputs directly to its corresponding output socket (mono in, mono out). However, both engines perform identical functions with synchronised parameters (determined from Engine 1's settings), thus producing high‑quality true‑stereo processing.

The last configuration is a dual‑mono mode which is structurally equivalent to the true‑stereo mode, with each channel's I/O being connected to just one engine. In this mode, though, the two engines remain entirely independent of each other for genuine dual‑mono operation, so you could (for instance) have an equaliser in one channel and a flanger in the other.


The M*One boasts a wide range of very usable reverb algorithms, as well as a good number of other essential effects and processes. The reverbs are categorised as Hall, Room, Plate 1 and 2, Spring, Live, and Ambience. Most share the same comprehensive range of parameters including decay time, predelay, size (early reflection pattern), high cut (low‑pass filter), high colour (HF damping), low colour (LF damping), reflect level, and reverb level.

Adjusting an effect is as simple as pressing the Algo/Edit button for the relevant engine and stepping through the available parameters with the cursor buttons. The displayed parameter is altered with the rotary encoder, whereupon the EDIT icon on the LCD illuminates to prompt the user to store the new effect.

Many of the other algorithms are delay‑based effects, starting with single and dual delay lines, each with a range of parameters including delay time(s), feedback, high and low‑pass filtering and panning. The chorus and flanger modes each provide 'classic' and '4‑voice' variations, the latter employing two 'classic' processes in series with phase‑reversed outputs for a thicker, more powerful effect. Similarly, the 'vintage' and 'smooth' phaser modes differ in that the first uses a four‑stage all‑pass filter algorithm whereas the latter increases this to a 12‑stage system.

The two pitch‑shifting algorithms (Pitch and Detune) are very similar, the detune mode simply having a restricted range. Both offer two independent pitch‑shifted outputs in addition to the direct signal, the maximum range of the pitch‑shifter being +/‑1 octave. The detune mode works extremely well for thickening a sound, and I generally prefer this technique over chorus as it doesn't suffer from the cyclic swirling effect. Unfortunately, if not surprisingly, larger offsets from the pitch‑shifting algorithm sound very artificial and the regular 'edits' are extremely obvious.

A parametric equaliser is available, with high and low shelving filters plus three parametric sections. The shelf slopes can be varied between 3 and 12dB/octave with +/‑12dB of gain swing, while the parametric sections provide the same gain swing over a 20Hz‑20kHz range. Bandwidth is adjustable from 0.1 to 4 octaves. A tremolo algorithm modulates the amplitude of the processed signal, offering a Hard mode with square‑wave modulation and a Soft mode with a triangular waveform. Both offer speed, depth and level parameters.

The dynamics section is particularly good, and easier to use than many equivalent functions in comparable devices. A compressor, limiter, gate (expander) and de‑esser are available, with gain‑reduction metering on the LCD. The compressor includes soft‑ and hard‑knee modes but no attack time parameter, whereas the limiter provides attack time without the knee options! Other than that, both algorithms share the usual range of parameters. The gate is fairly typical of the genre and works well enough, although the provision of a depth parameter to limit the maximum amount of gain reduction would have been a useful addition. The de‑esser is a fairly simple version, similar to the limiter but with the addition of a parameter for the centre frequency of a side‑chain.


  • Very usable reverbs.
  • Useful range of additional effects.
  • Intuitive operation.
  • Flexibility of configurations.


  • No gearing to the rotary encoder.
  • Menu selection to change between User and Factory presets.


A good quality reverberator with a useful selection of additional effects and considerable flexibility in its configuration. Minor operational niggles are completely outweighed by the attractive price.