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ART Multiverb Alpha

Article from Sound On Sound, January 1992

The Multiverb Alpha is the latest and greatest in ART's series of studio multi-effects processors. Dave Lockwood checks it out.

Despite initial impressions, ART's Multiverb Alpha is more than just a Multiverb with a 'multi-function rotary encoder' for easier data entry (I won't call it an 'alpha dial' in deference to Roland). Using a new 24-bit ASIC system, the Alpha offers enhanced processing resolution, compared to the 20-bit previous models. As far as the average user is concerned that simply means a cleaner, more complex, or perhaps more natural sound, depending on the effect, and more effects combinations; you can now have the two processing heavyweights, pitch transposer and reverb, at the same time. If you have not yet added 'ASIC' to your acronym collection, it stands for Application Specific Integrated Circuit.

Up to six effects are available simultaneously, with a 20kHz audio bandwidth (44.1 kHz sampling) and nominal signal-to-noise ratio in excess of 90dB. Two analogue processing stages have been added prior to the digital effects: a 7-band equaliser, and an 'Acoustic Environment Simulator' (AES). Like previous Multiverbs, the Alpha offers a generous 200 memory locations, all of which are available as user-memory if necessary. The first 110 slots contain the factory programs, which are initially write-protected to prevent accidental overwriting, but can be 'unlocked' when you have used up the 90 'blank' locations. (Don't worry about losing anything useful, because factory presets can be recalled individually.)


The Multiverb Alpha is housed in a 1U, predominantly black rack case, with integral PSU; all audio and external control connections are made to the rear panel. Unbalanced 1/4" jacks (1MOhm input impedance, 1kOhm output impedance), handle both input and output, with the 'dry' signal remaining in stereo through to the output whilst the processed signal is derived from the sum of the two inputs. Separate MIDI In, Out and Thru connections are featured, plus two assignable footswitch jacks. Unusually, there is also a 9v DC output, which uses a standard 3.5mm mini-jack socket and therefore looks like another input! Although this would be ideal for powering any 9v pedals, I suspect its main reason for inclusion is as a potential power source for ART's X15 Ultrafoot remote MIDI control system (see box).

Two short-travel sliders, mounted horizontally on the front panel, are used to control input and output levels, which are monitored by green, yellow and red LEDs. The unit proved to be very tolerant of level settings — short-term clipping produced no audible complaint, and there were no particularly dire consequences in terms of quantisation noise or 'crunching', when under-driven. Centre-detents indicate unity gain at the nominal (+4dB) line level, with plenty more gain available to cope with a wide range of interface requirements, including direct connection of relatively low-level instruments. There is no front-panel 'mix' control, for the output mix is a programmable parameter which can be set for every preset.


Control of the Multiverb Alpha is performed primarily from the Rotary Encoder (a continuous mechanically stepped pot), and its four associated primary mode switches, designated Preset, Mix, Parameter and Value. In Preset mode, you can recall patches either by scrolling through memory locations with the data entry pot, or by keying in a number on the dual-function numeric keys. A leading zero is required for single digit locations, and the system always waits a couple of seconds to see if you are going to input any more figures (during which period it continues to process via the previously selected patch before executing a glitch-free switch to the new one). The 2-line LCD shows the program name (its number appears on the 3-digit LED) and an abbreviated listing of the effects (and their order) that it uses; there is also an indication of the number of real-time MIDI controllers assigned to the preset.

Quite correctly, the Mix parameter has not been buried deeply in the FX data and remains always instantly accessable as a primary mode via the dedicated Mix key. Repeatedly pressing Mix cycles you round output values for Dry level, FX level and Dry EQ level. 'Dry EQ' is a separate output from the analogue stage; where EQ and/or AES are performing fundamental tonal shaping, it makes sense to use this output as the 'normal' signal to balance against the effect, rather than the totally unprocessed 'Dry' signal.


You can enter Edit mode either via the dedicated Edit key, or by hitting either of the remaining mode switches, Parameter or Value. The parameters and data values making up each preset can then be scrolled either via repeated key presses or using the rotary encoder. The quickest and most logical method of editing however seems to be to use the Value key to advance the selected parameter whilst the encoder pot is used to alter its value. The Parameter key, in this mode, allows you to step backwards through the process; if you have ever used a device where that was not permitted, you will know just how welcome a facility that is!

Putting extra effects into a preset, or removing them, is achieved with dedicated 'Add Effect' and 'Delete Effect' switches, making the process about as simple as it could be. As you add more effects, you have fewer options of what else to throw into the mix, as the system automatically calculates what is possible within the processing power remaining. For example, if you start work on a blank preset by entering the Pitch Transposer algorithm, you immediately find that only one type of reverb (the least complex) is now available to you, and that the DDL delay time is limited.

As I have said of previous models, I like the Multiverb operating system. I appreciate the amount of logic that it brings to the process, thus I do not mind that a parameter such as 'position in the chain' is rarely offered. To me it seems to be offered when it is relevant, primarily around the modulation effects, and the rest of the time the system makes the only sensible choice. There may be one or two users, of a more experimental inclination, who will be frustrated at not being able to put anything anywhere, but the rest of us will probably simply appreciate the efficiency that the system brings to a potentially complex array of options. Perhaps the one glaring omission is the lack of a facility for copying a preset to another location to use it as a starting point for editing. This is easily overcome via an external Sys Ex exchange, but should not be necessary.


The first effect in the chain is one of the two analogue processes on-board, the 7-band EQ. Good digital equalisation is a very sophisticated process, tying-up a lot of processor power, and even then it doesn't always sound subjectively 'right'. In most situations, digitally controlled analogue is still preferable, and that is what we have here. 15dB of boost or cut is available at 'stretched octave' intervals of 40Hz, 100Hz, 250Hz, 640Hz, 1.6kHz, 4kHz and 10kHz. Gain is not in individual dB steps however; you're limited to 2, 4, 6, 9, 12 and 15dB settings, which slightly compromises on precision. There is no bandwidth, or 'Q', parameter, although the preset Q is broad enough to keep things from getting too harsh and coloured when several bands are used simultaneously.


In spite of its grand title, this facility appears to offer simply a range of preset EQ curves, simulating varying amounts of high-frequency absorbant material around the sound source. Full of evocative names such as 'Wood + Tile', 'Pews/People' and 'Stone Ceiling', it still sounds like an EQ to me, and no more simulates these acoustic environments than you or I could with a graphic equaliser (which is to say, not very much). I must say however, I find the actual facility of a range of preset EQ curves really quite useful, and take issue only with the concept of its presentation here. ART obviously view this a little differently. I quote: "Better than an equaliser, the AES program actually knocks out frequencies all over the entire spectrum, simulating real world acoustics." You will have to make your own mind up on that one.


The digital effects begin with the Low Pass Filter. A choice of one of 30 roll-off frequencies between 17.8kHz and 630Hz, permits the LPF great precision. Operating only on the feed into the FX stage, it is useful for softening delays, taking the harshness out of fierce modulation effects, or keeping effects in the correct perspective in relation to the dry signal.


The Flanger offers Speed, Width and Regeneration parameters, and can be selected to appear Pre or Post any delay/reverb effects that may also be in the chain. As I have mentioned in previous reviews, the Multiverb flanging programs are particularly strong, with the ability to get a decent 'flange' out of virtually any source.

Chorus similarly has Width and Speed controls, although Regen is replaced by Delay, setting base delay time, which is much more useful for chorusing. Again you have a choice of placement before or after delay effects, so 'chorused reverb' is an option. As usual with digital chorusing, given only one modulation source and waveform, there is some difficulty in achieving sufficient richness without excessively obvious pitch variation. However, used in combination with other effects to add greater time-domain complexity, some of the Multiverb Alpha's chorus-based factory presets proved to be really rather good.


The Pitch Transposer algorithm offers an octave shift in either direction, as well as a micro-shift option. There is a choice of three algorithms, offsetting speed against quality: Smooth, Normal and Quick. The Quick setting is is recommended for percussive sounds where the unavoidable processing delay would be exposed, whilst Smooth is significantly cleaner but does introduce an obvious delay. The Fine Tune parameter available for detuning effects still has the 6 cent step resolution I complained about in my reviews of earlier Multiverbs. Single cent steps, at least for the first few cents on either side of 'unity pitch', would be preferable. Perhaps the biggest regret, leaving aside that ART haven't managed to incorporate 'intelligent' harmonising, is that the Transposer is still mono, disallowing simultaneous up and down micro-shifts.

Pitch Shift Regeneration is included, and there is also the facility to define the shift interval with MIDI note data. Using a sequencer (preferable to 'live' input simply because you can optimise the timing of 'control' notes), it is just possible to overcome the lack of intelligent harmonising — you can set a different transposition interval for every note if necessary, overcoming the inherent restriction to non-scalar, and rather musically limiting parallel harmonies.


The autopanner has just two parameters; Modulation, controlling the width of the pan, and Speed to set the rate at which it will move (0.04Hz to 27.3Hz). MIDI Pan has now been added, allowing pan position to be determined precisely and controlled in real-time from a MIDI continuous controller source. Another addition is Tremolo (amplitude modulation, or variation in loudness), with Modulation (Depth) and Speed parameters. For Pan or Tremolo to work most effectively the dry signal must, of course, be removed from the output.


The comprehensive and sophisticated range of delay options can be divided into three main categories: Stereo; Regenerated; and Multi-tapped. Each type of delay is further divided into Short and Long variants. Regenerated delays offer only control of Delay Time (in coarse or fine increments), Regeneration, and Level, with maximum delay times of 1100ms (Long), and 960ms (Short).

Independently variable Stereo Delay is available up to a maximum of 1350ms per side (1150ms Short). A further parameter is also added to this algorithm in the shape of HF Damping, which rolls off high frequencies from succesive delays to produce a more natural effect.

The ART multi-taps are particularly versatile; up to seven taps are available, with a choice of three amplitude characteristics (successive taps can get louder, quieter, or remain at the same amplitude). It is also possible to vary their relative spacing. Adopting the Lengthened characteristic will cause the taps to become progressively farther apart towards the pre-determined delay time, while Shortened causes them to get closer towards the end of the cluster. Whether it is enhancing the complexity of reverb or modulation effects, spatial simulation, or 'doubling' without modulation, there appears to be no multi-tap application that the ART won't do to a high standard.


The ART Reverbs can be divided into Natural and Gated reverb algorithms. The Natural set has four basic 'characters', with three alternative levels of quality. Hall, Room, Plate and Vocal are the basic types, with variants 1, 2 and 3 offering increasing levels of complexity and density. Type 1 programs are generally used in combination presets where reverb is not the main effect, the highest quality Reverb 3 algorithms being used for that purpose. Of the fundamental characters, Plates simulate the smallest space, and tend to be bright and dense, whilst Halls are more natural and diffuse. The Room and Vocal programs both have more prominent discrete reflections, giving more animation and support to the sound.

The basic parameters remain the same for all the Natural reverbs; Decay Time can be varied, in increasing step sizes, up to a maximum of 25s, and you can apply HF Damping to prevent an unnaturally bright decay. A most effective Position parameter, varying the relationship between the early reflections and the diffuse field, allows you to place the listening point anywhere between the front and the back of the simulated acoustic space. Reverb can be placed before or after accompanying delays.

Only Reverb 3 has a Diffusion parameter (four levels), to determine the smoothness of the reverb field, and control the extent to which discrete reflections can be heard in the decay.

ART reverbs always have tons of character; these are bright and clean, perfectly reflecting modern production values. Some of the presets have been particularly well programmed; a subtle parallel delay or two, or just the right EQ pre-voicing sometimes makes all the difference between programs that do something magical in context, working hard for you as opposed to just being there.

The Reverbs are completed by the three Gate-verb algorithms. There are two main parameters, Decay (up to 400ms) and Diffusion, with a further choice of Sloped, Flat or Reverse characteristics determining the decay amplitude. Sipped allows some decay before the abrupt cutoff, whilst Reverse has effect of 'swelling' the decay, culminating in a repeat of the attack; Flat is of course the classic, dense burst of ambience which is abruptly terminated into silence.


Three sampling options are provided, Short, Long, and Sampler + Pitch Transposer. Maximum sample time, with the Long algorithm is just under 2 seconds. Audio level, Manual, or MIDI note triggering can be used to initiate recording. Playback options include Single (one shot), Repeat (looped), MIDI mode (plays whenever a Note On message is received) plus audio triggering (called 'Punch-in'; the signal present at the input is replaced by the sample). Using the Sampler + Transposer option enables playback at different pitches under MIDI control. The Short Sampler algorithm can also be combined with a limited range of reverbs (Types 1 and 2 only). The recorded section's playback can be truncated from both ends via the Start and Length parameters. Samples cannot, however, be stored on-board, nor can they be downloaded to an external storage device via MIDI.


For real time MIDI control of the Multiverb Alpha, you can assign up to eight parameters to respond to MIDI control sources. A MIDI control assignment consists of four elements: the effect parameter to be controlled, the controller number of the source, plus maximum and minimum data values (inverted response can be achieved simply by setting minimum above maximum).

Controllers 0 to 120 are available, plus note number and velocity for both Note On and Note Off events separately. Channel Pressure, Polyphonic Pressure and Pitch Wheel complete the recognised sources. Although in theory any source can control any parameter, in practice, some assignments inevitably make more sense than others, particularly for 'performance' control as opposed to remote control from a sequencer.

Any conveniently located continuous controller, such as a Data Entry slider (Controller #6), or Foot Controller (Controller #4) is obviously suited to regulating a major parameter such as reverb decay time, delay level, or flanger regeneration. More stimulating however, are assignments related to playing action which allow effects to respond to the player's touch. It helps if your assignments have some musical logic to them; Note On velocity to Reverb level would be a bit of a waste of time, for louder and brighter notes will tend to create more of a tail anyway. Aftertouch to Reverb level, however, gives you some control after the transient phase where you would not normally be able to influence events.

Real-time MIDI control from a sequencer can be far more sophisticated and precise. Firstly you are not limited to the number of sources you can physically manipulate at the same time; the maximum eight controllers can all be active simultaneously via programming. By assigning a controller to each of the bands of the 7-band equaliser you create quite a sophisticated dynamic EQ, very useful for subtle real-time repair work, such as taking-out a vocalist's 'pop', or lifting presence on an off-mic word. Because the MIDI control data can be edited (on a sequencer) in such detail, you can invariably achieve the desired effect with great precision.

Any unit which incorporates real-time MIDI control should respond quickly to data, and it's important that glitching in the audio output is minimised when parameters are modulated. The Multiverb Alpha appears to have a limitation in this area; even a single controller operated quickly can be sufficient to over-run the MIDI data buffer, producing audible glitching on some programs and a "MIDI Data Error" display. Some units respond to discontinuous data in this way, but in the case of the Alpha it would definitely appear to be speed related. This was confirmed during testing by progressively slowing down the data speed until a 'critical rate' was reached where the problem did not occur. Increasing the data load produced a recurrence.


The factory presets begin with eight very effective general ambience treatments, in varying sizes and characters, from 'Bright Vocal Room' to 'Carnegie Hall'. The dedicated vocal and guitar treatments that follow are, as in previous Multiverbs, among the strongest programs, with most of my old favourites having equivalents in the new model. There are also plenty of dedicated drum treatments, ranging from general programs such as 'Rock Concert Kit' (thunderous, distant perspective) and 'Clean Drum Verb' (very nice, tight ambient reinforcement), to the highly specific, such as 'Snaregate' (a quality gate program which doesn't obscure the character of the original signal).

The remainder are perhaps more specialised, including a better Leslie simulation than on previous models, and some programs specifically set up for MIDI foot control, including 'Cry Baby', a rather unconvincing wah pedal simulation using a MIDI foot controller to sweep the bands of the equaliser through different ranges. Don't fail to check out 'Sax Ballad' however, on any solo lead instrument. Stick your guitar through that one and you won't want to stop playing.


ART's new Multiverb Alpha is a solid, verastile performer, with some areas of excellence, and is particularly to be commended for its ease of programming. The intrinsic sound quality will be appreciated by the discerning user, although the full potential of the MIDI specification appears, at least in the review model, to be compromised by the data handling limitation.

The multi-effects market is more competitive than ever now, but I am sure that the Multiverb Alpha has enough of an individual character to carve out its own sector. Every unit of this type will inevitably have its own particular strengths and weaknesses; I will have to leave it to you to decide if the Alpha's strong points coincide with your needs.

Further information

ART Multiverb Alpha £319 inc VAT.

Harman UK, (Contact Details).


The X15 Ultrafoot is a multi-footswitch unit dedicated solely to MIDI remote control functions. Provided with two rocker-action pedals and a bank of 14 footswitches, the Ultrafoot transmits MIDI Program Numbers and Control Change information. Both pedals and switches can be freely assigned to any controller number, should the default values not be suitable, allowing the unit to function in any MIDI effects system, rather than just with ART units. Presets are included in the Multiverb Alpha however, and other more performance orientated models such as the SGX, to take specific advantage of the Ultrafoot's capabilities.


The sturdy board is of all-metal construction, with footswitches mounted under domed rubber caps. These are a little short on tactile feedback for my liking, particularly in this application; rather like a poor quality membrane switch, you are never quite sure whether you have pressed it hard enough or not, and although there is visual confirmation from an LED, these are placed right next to the switches and are therefore obscured by your foot! For a device that basically does nothing apart from footswitching, something as fundamental as the switch action should have been beyond reproach.

With 'Murphy's Law of Live Performance' in mind, I was disappointed to see that an external 9v power supply is required, and that all connections are totally exposed on the rear face of the unit — I guarantee that somebody, somewhere will accidentally step on one these connectors during a gig.

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Publisher: Sound On Sound - SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.

The current copyright owner/s of this content may differ from the originally published copyright notice.
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Sound On Sound - Jan 1992

Donated & scanned by: Mike Gorman

Gear in this article:

Studio/Rack FX > ART > Multiverb Alpha

Gear Tags:

Digital FX

Review by Dave Lockwood

Previous article in this issue:

> The Rough Guide To Choosing ...

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> A Modern Classic

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