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Digitech TSR12

Studio Reverb & Multi-effects Processor By Derek Johnson
Published November 1994

Is the lower‑priced brother of the powerful TSR24 destined to find its way into the studio racks of the UK, or simply become part of the EC effects processor mountain? Derek Johnson finds out.

In the world of hi‑tech music products, it's almost a truism that if a certain technology is introduced in a product at a high price, a more affordable version won't be far behind. It happened at Yamaha with several generations of FM synthesis and it's happening at Digitech. Not only has the Vocalist family of harmony processors become available at different price points, but the company's powerful TSR24 has spawned its first spin‑off. Based around Digitech's proprietary S/DISC (Static/Dynamic Instruction Set Computer) technology, the TSR24 was reviewed in December 1993; it offered a 48kHz sampling rate, 24‑bit processing, user‑definable algorithms, true stereo processing and pseudo‑quadraphonic output — a powerful effects processor by anyone's standards. The new TSR12 retains the S/DISC processor and squeaky clean signal path, but cuts back on other facilities. However, it's no poor relation, offering quality effects in an accessible and affordable package. And, because it dispenses with the TSR24's 'roll your own algorithm' facility, it's also easier to use.

At the heart of the TSR12 are 31 preset algorithms (plus a dry signal path), each of which contains a minimum of three and a maximum of five Effects Modules. Modules include reverbs (maximum 20‑second decay), delays (maximum 1.4 seconds), modulation effects, pitch shifting (+/‑24 semitones), a 1.5 second sampler, parametric and graphic EQ, and a noise gate. All algorithms also feature one or more mixer modules that allow the outputs of the various effects modules to be mixed together in interesting ways. These algorithms form the basis of TSR12 Programs — there are 256 on board, divided into 128 preset and 128 user‑definable programs. The presets include a wide variety of usable treatments, including all manner of reverb environments and multi‑effects options. The User Programs initially contain duplicates of the factory settings.

A slightly curtailed, but still eminently usable, MIDI spec has made its way into the TSR12's operating system: useful MIDI features include the ability to assign up to four MIDI Controllers per Program to any four parameters, for remote realtime control, input filtering and transmit and receive mapping. The TSR12 also maintains a 48kHz sampling rate and 24‑bit internal processing.

The Look

Physically, the TSR12 offers no great surprises, with a traditional but attractive front panel. The display is divided, in typical Digitech fashion, into three distinct sections: a 2‑line by 16‑character LCD, a 3‑character alphanumeric LED Program number display, and an input level meter. Also in this vicinity are the Bypass indication LED and a processor Overflow LED. When lit, this last LED indicates that the CPU is being pushed hard and that distortion is, or will imminently be, audible; let your ears be the judge — if the LED flashes and the output signal sounds fine to you, then it's probably OK.

Most of the front panel is taken up with three groups of buttons, labelled Program, Parameter and Effects Library. The first two groups are self‑explanatory, being used to select Programs or to edit them, while the Effects Library buttons — labelled Reverb, Delay, Chorus, Pitch Shift, Sample, EQ, Flange, Modulation, More and Mix — are used to quickly access Effects Blocks within a Program, which saves you from scrolling through what can be a rather large list of parameters while editing. All that remains are three buttons labelled Name, Utility/MIDI and Bypass, plus input and output level controls. The rear panel offers stereo inputs and outputs, a footswitch socket and MIDI In and Out/Thru sockets. In spite of the TSR12's compact size — it's only 15cm deep — it features an internal power supply. Well done Digitech!


The TSR12 fires up in Performance mode, and it is from here that you access the factory programs — using the Program up or down buttons, or MIDI program change commands. The menu architecture of the TSR12 is linear, and rather than featuring a multi‑level system, with nested sub‑menus, all editing parameters and functions are included in a single level and are accessed using the parameter left and right buttons. This may seem rather odd, but actually makes for quick and easy operation, since a) you never get lost — just keep scrolling — and b) the Effects Library buttons offer convenient short cuts for getting to specific effects quickly.

The easiest way to start creating programs of your own is to edit the factory programs; the manual, to its credit, provides several step‑by‑step examples. Choose a Program you wish to edit and, using the Parameter Left or Right buttons, scroll through the available parameters and alter their values. The first choice to your right is the algorithm, and after that you get each parameter for each effect in the order presented by that algorithm. As I mentioned earlier, life is made easier by using the Effects Library buttons to jump instantly to the first parameter of any Effect Module in an algorithm; it stands to reason that if an effect is not included in an algorithm, pressing its button will have no effect. It's a shame there's no way to indicate which effects are or aren't used in a particular algorithm, such as LEDs on the front panel. In order for the TSR12 to remember any changes made in this way, the result must be stored in a user position — change program now and your work is lost.

The parameters available are actually very comprehensive; for example, algorithm 10, 5‑band Parametric EQ followed by Big Reverb, consists of:

  • Noise Gate — with threshold, hold time, attack time, release time attenuation and delay time parameters.
  • Parametric EQ — with low shelving frequency, low shelving gain, frequency, Q and gain for all five bands, high shelving frequency, hi shelving gain and level parameters.
  • Reverb — with Early Reflection pre‑delay, ER spread, ER shape, ER diffusion, ER level, reverb pre‑delay, reverb spread, reverb diffusion, reverb high‑frequency decay, reverb high‑frequency roll‑off, reverb size, reverb time, reverb level parameters.
  • Master mix balance.

Other algorithms have even more parameters available, but it looks more daunting on paper than it actually is in practice.

How It Sounds

Assessing the sound of any processor is subjective; however, review protocol calls for at least a stab. Overall, the 48kHz sampling rate results in a very clear, bright sound. Delays and samples are pretty much exact replications of the input signal, choruses and flanges have a subtlety and richness to them, and the reverbs — especially the dedicated reverb algorithms — are sparkly and slick. Overall, effects are truly exciting, and the TSR12 really gives you the urge to go and mix. If you have an average track, the TSR12 will add an appealing sheen, making even a straight‑ahead vocal sound as though it's really been 'produced', and if you have a good or great track, it provides you with the potential to give it something really special. In fact, I used the TSR12 with a vocalist who is very demanding about the quality of reverb that she sings with, and she was just as impressed with Digitech's new box as I was.


I've probably given my overall opinion away with my description of the TSR12's sound. However, the unit is not completely without demerit points. First of all, there's the manual: while it does provide hands‑on examples to ease the new user into confident operation, there are places where it's a little lacking. It doesn't really give you any insight into what the TSR12 is capable of, and in a couple of places inaccurately describes or misses out particular parameters. I will note that the manual with the review unit appeared to be a pre‑production version, since one or two effects modules are actually different in the machine itself (for example, the manual lists only a 15‑band graphic EQ module, whereas some algorithms use a 10‑band graphic).

Another negative point is with regard to overloading, which is rather easily done, especially since the difference in allowable send level from my desk differed vastly between different Programs. The manual makes it clear that hyping up the parameter values of some effects will alter the sensitivity of the overall Program, often to detrimental effect. You need to keep track of tweaks to programs, input sensitivity and output sensitivity. Often, the processor will overload when the input level is apparently hardly registering.

I'll also briefly moan about the otherwise fine sampling facility: a sample can't have its pitch altered, and it can't be triggered by a MIDI note. A maximum length of 1.5 seconds seems a bit mean too. Naming programs is also a tad slow: the fact that there's no parameter knob means that you have to punch in letters with the parameter buttons.

Enough negativity — I was truly impressed with the TSR12. The combination of an exciting sound, quiet and clean operation (due, no doubt to the 48kHz sampling rate and 24‑bit internal processing), ease of use and just enough MIDI sophistication, plus a mid‑range price tag equals an enticing package. While £479 may seem just a little high to be calling mid‑price, I have it on good authority that a realistic street price will be well under the £400 mark, so shop around. Whether you're buying your first multi‑effects processor on a budget, hunting for the reverb, or just looking for another quality processor to add something a little different to your sonic arsenal, then the TSR12 should be somewhere near the top of your list.

What's Missing

If you're reading through this review without reference to the technology that begat the TSR12, then perhaps it's time for a few words about the TSR24 — check out Paul White's review in December 1993's SOS for the full story. Basically, the TSR24 offers the same S/DISC technology but with more power and user programmability. The most important features are true stereo processing — you can even set up two independent effects chains — and the ability to create your own algorithms. This task can appear to be slightly daunting, but a little planning goes a long way. Other nice touches are four outputs for dual stereo or pseudo‑quad effects, even more MIDI control and a big alpha dial for parameter changes.

Favourite FX

It's especially hard to pick out any favourite Programs amongst the TSR12's factory settings, because they're all so good, and also because I was coming up with my own Programs almost immediately. However, here goes:

  • 1 Big & Bright Reverb: immediately shows off the quality of the Big Reverb Effects Block; start here for all your reverbs. You could also have a go with Programs 44 to 82, which are a solid block of reverbs: large and small rooms, arenas, plates, clubs, garages, churches, you name it.
  • 9 Sparkle Fifths: uses pitch shifting and two‑tap delay to add a brilliant little shimmer to your sound. This is excellent on synth strings.
  • 24 Delays in a Pan: four‑tap delay and autopanner moves the sound image subtly back and forth between speakers (or ears, if you've got your cans on).
  • 85‑102: offer various medium and deep choruses, phasers, flangers, detuners, all of excellent quality. Whether you want subtle or deeply thrilling modulation effects, look no further.
  • 123‑126: delayed chorus, detune, flanger and phaser. This range of effects should give you a couple of new ideas. Sometimes you just don't need reverb.


There follows a list of all algorithms listed in the TSR12's manual. Note that all algorithms include a noise gate and some form of EQ at the start of the chain, even if the algorithm's name doesn't mention it.

  • 1 Dry Path
  • 2 Delay, 8‑Voice Chorus
  • 3 Chorus, Dual Arpeggio, Delay
  • 4 Chorus, Dual Pitch Shift, 4‑Tap Delay
  • 5 15‑Band Graphic EQ, Delay, Dual, Chorus
  • 6 15‑Band Graphic EQ, Delay, Detune
  • 7 15‑Band Graphic EQ, Delay, Flange
  • 8 15‑Band Graphic EQ, Delay, Phaser
  • 9 10‑Band Graphic EQ, Big Reverb
  • 10 5‑Band Parametric EQ, Big Reverb
  • 11 Chorus, Reverb
  • 12 Detune, Reverb
  • 13 Flange, Reverb
  • 14 Tremolo, Phaser, Reverb
  • 15 3‑Band Parametric EQ, Delay, Reverb, Noise Gate
  • 16 5‑Band Parametric EQ, Chorus, 2‑Tap Delay, Stereo Autopan
  • 17 3‑Band Parametric EQ, Chorus, 2‑Tap Delay, Reverb
  • 18 3‑Band Parametric EQ, Detune, 2‑Tap Delay, Reverb
  • 19 3‑Band Parametric EQ, Flanger, 2‑Tap Delay, Reverb
  • 20 3‑Band Parametric EQ, Phaser, 2‑Tap Delay, Reverb
  • 22 5‑Band Parametric EQ, Chorus, 4‑Tap Delay, Pan
  • 23 5‑Band Parametric EQ, Detune, 4‑Tap Delay, Pan
  • 24 5‑Band Parametric EQ, Flange, 4‑Tap Delay, Pan
  • 25 5‑Band Parametric EQ, Phaser, 4‑Tap Delay, Pan
  • 26 Pitch Shift, Reverb
  • 27 3‑Band Parametric EQ, Gated Reverb
  • 28 Sampler, 15‑Band Graphic EQ
  • 29 5‑Band Parametric EQ, Delay, Ducked Reverb
  • 30 Chorus, Ducked Reverb
  • 31 5‑Band Parametric EQ, Modulated Delay, Reverb
  • 32 5‑Band Parametric EQ, Pitch Shift, 4‑Tap Delay, Auto Pan

Brief Specification

  • 20Hz‑20kHz bandwidth
  • 48kHz sampling frequency
  • 128 preset Programs, 128 user Programs
  • 24‑bit signal path
  • Integrated MIDI processor
  • Built‑in MIDI merging
  • MIDI input filtering
  • MIDI transmit and receive mapping
  • MIDI control of parameters


  • Slick and sexy reverb.
  • Clean and quiet operation.
  • Easy to use.
  • Excellent value.


  • Not true stereo.
  • Can overload easily.


An exciting, well‑designed product at a price that's right. If there's any justice, the TSR12 will become something of a fixture in home studios, keyboard rigs and live processing setups.