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Behringer REV2496 V-Verb Pro

Modelling Reverb Processor
Published August 2004
By Paul White

Behringer REV2496Photo: Mike Cameron

Behringer's new digital effects box models the characteristics of well-known high-end and vintage reverberators.

Behringer's new REV2496 (also known as the V-Verb Pro) has been designed to offer both high-end room simulation and emulations of high-end electronic reverb devices. In all there are 14 effect algorithms, eight dedicated to reverb and the remainder producing a wide range of delay-based and dynamics processes. In addition to this, the REV2496 offers two largely independent channels of processing, each running on its own DSP engine, and it's capable of working at up to 24-bit/96kHz resolution with no loss of functionality at the higher sample rates.

The unit has two fully balanced analogue inputs, four servo-balanced analogue outputs (servo-balanced outs can be used to feed either balanced or unbalanced destinations with no change in level) plus stereo digital I/O in both AES-EBU and optical S/PDIF formats. The digital input may be used at the same time as the analogue inputs for true dual-stereo operation. The analogue I/O is on both TRS jacks and XLRs, and word-clock input is available for synchronising to external sources, but only when using the analogue inputs. Various dithering options are included for outputting at 24-, 20- or 16-bit resolution, and MIDI In, Out, and Thru sockets are also included.

There are 10 different routing options that allow the reverb engines to be used entirely independently or in a number of series and parallel configurations. On examining these more closely, some would be useful for surround processing, as they allow one reverb engine to feed one set of outs before passing that signal through a further set of processing to feed the second set of outputs. It's also possible to use the two reverb engines as mono-in, stereo-out processors fed from two effects sends and returned to a single stereo effects return. Or you could return to two separate stereo returns, as there are four analogue outs and one stereo digital output.

The Hardware

Housed in a smart 1U case and powered from an internal switched-mode PSU (with automatic mains sensing from 100 to 240 Volts), the REV2496 has a custom LCD display showing both alphanumeric information and graphics, styled much like that used in the Behringer DDX3216 digital mixer. Each effect has up to 30 editable parameters, but to keep life simple the four most important parameters for each program are mapped to four 'turn and push' data knobs for instant access. A further large data knob is used for patch selection, and everything else is accessed using 12 clearly labelled buttons. There's plenty of storage space within the RAM and ROM for a total of 400 program banks.

Sharing the window with the main display is a pair of LED meters to monitor the two input signals, a MIDI activity light, a sample rate (or external sync) indicator and a Limit LED. The output section includes a pair of stereo peak limiters to avoid clipping, and if either one of these is goaded into action, the Limit LED will illuminate accordingly. Excessive limiting doesn't sound good, but if you treat these limiters as a safety net, they'll prevent embarrassing overloads.

Each DSP engine has its own select button, where one engine generates one stereo effect. Additionally, there are several Combi programs, accessed via the Combi button, where both engines work together to create a more complex combination effect. The Edit key gets you deeper into editing if the four instant-access knobs don't do the trick, and hitting the Graph key lets you see a graphic of the reverb tail or the delay arrangement or whatever is relevant to the current algorithm as an alternative to the raw numbers, though the control functions remain the same.

Each menu can have up to four pages accessed using the Page button, and of course there's a Store button for saving user patches. A Compare key is available for comparing edited and unedited versions of a program and there's the usual Setup key for configuring all the behind-the-scenes stuff such as MIDI settings, output bit depth and dither, and other global functions. The digital clocking options are handled from within Setup, as is the selection of mono or stereo input.

A further option allows some adjustment (±6dB) over the digital and analogue output levels, though the output limiters are preset and always in circuit, so no further adjustment of these is possible. By way of MIDI options, different channels may be selected to address the A and B engines, and in addition to SysEx dumping and loading of patches, the unit responds to Program Change and Continuous Controller messages.

The Bypass button is, as always, a little more clever than it seems, and the way it works depends on how the Wet/Dry Mix parameter is set in the Setup menu. If set to Intern, then Bypass simply shuts of the processed part of the signal leaving the dry signal intact, whereas if set to Extern, Bypass mutes the entire output. When using the REV2496 with a mixer, you'd normally be working in Extern mode. The OK/Tap button acts as an enter key or a delay/LFO rate entry device — when setting tempo, the unit takes an average of the last four taps.

Behringer REV2496Photo: Mike Cameron

Reverb Algorithms

The V-Verb algorithm is the biggest and meanest reverb program in the box, designed primarily for realistic space simulation. It incorporates pre-delay; both low-cut and high-cut filters before the early-reflections generator; and similar filters before the reverb-tail generator. The early reflections can be adjusted in stereo width, and of course there's also a room-size adjustment. Full control is available over the ER/Tail balance, the decay tail can have its decay time varied over a large range, and the decay in different frequency bands can be adjusted so that, for example, high frequencies die away faster than low frequencies. Reflection density is variable via the Diff parameter, and there are both cyclic and random modulation facilities available to influence the reverb tail, adding complexity and shimmer.

The V-Verb algorithm offers three types of room simulation (Concert Hall, Cathedral and Theatre) based on the same algorithm, but with different early-reflection patterns. The Theatre option is further subdivided into more choices for Area, Club, Stadium, Stage, Studio, Opera, and Amphitheatre. Apparently the early reflection patterns used in the Concert Hall version are based on the reflection pattern measured in a top concert hall, though as far as I can determine the early reflections are entirely synthesised and not based on convolution techniques.

Before digital reverb, most studios used Plates, one of the best known being the EMT Gold Plate. The Gold Plate emulation algorithm offered here has a parallel structure where a reverb generator (with pre-delay and modulation) runs in parallel with four delays that are summed into a diffusion generator to create artificial early reflections. Reverb decay time is adjustable, as are high-frequency damping and bass decay (which can be set as a multiple of the overall decay to increase the bass decay time). The Diffusion parameter allows the early-reflection density to be adjusted. All in all, there's a lot more to tweak here than with a real plate reverb.

Next in line is the Ambience section, which also includes the closely related gated and reverse reverb options. Ambience creates a sense of space with the minimum of reverb tail, which helps keep busy mixes free from clutter. The size of the simulated space can be adjusted, while the gated version has variable attack (in this case attack simulates the density of the reflections at the start of the reverb, not the rise time) and density. Reverse reverb also has a variable rise time that simulates the effect of backwards reverb by applying a slow-attack, fast-release envelope to a long burst of early reflections. Various tonal tweaks are available.

Multi-effects Treatments

After the reverbs come the assorted effects, starting with that old standby delay. This has a separate pre-delay for each channel, and both the left and right channels have independently variable delay times. EQ is available both before the delay and in the feedback loop, so it is possible to approximate a tape loop echo effect. The X-Over Delay effect uses a crossover network to divide the input into three frequency bands, where each feeds a fully adjustable delay line with additional pre-delay (which comes before the feedback loop). The levels of the three delays can be adjusted, and feedback is also independently adjustable for all three delay lines.

The Chorus/Flanger effect offers the usual modulated delay treatments, again with pre-delay and with the addition of an LFO-controlled panner. EQ is available prior to the effect, and the LFO's rate can be modulated by the envelope of the input signal, which can lead to less obviously cyclic effects. The chorus engine can be set to four, six, or eight voices, and the pseudo-stereo output obtained from these can be adjusted in width. In multi-voice mode, adjusting the pre-delay sets up a slightly different pre-delay for each voice to create a richer effect. Further adjustment of the relative phase of the LFO modulation is possible to add further complexity to the multi-voice chorus effects and the panner, which runs from its own LFO and can be set manually or synced to your track's tempo.

The Phaser algorithm also gets the 'added value' treatment with input EQ, LFO modulation of resonance and delay time, and further EQ in the feedback path. The LFO phase between the left and right channels can be adjusted to give an impression of stereo width. Even the Tremolo effect has a few little twists, such as a variable triangle-to-square modulation waveform, tempo sync, LFO rate modulation via the input signal (with attack and release rate controls), and variable left/right phase.

Although compression is a process rather than an effect, the REV2496 includes a compressor with look-ahead delay, split-band facilities (so that, for example, you can apply compression only to high frequencies for de-essing and suchlike), and side-chain EQ to make the compressor frequency conscious (again necessary when de-essing). There's also a transient-bypass feature that allows brief transients to escape processing, which can help retain clarity with heavily compressed, fast-attack sounds such as percussion.

Presets & Editing

As with most effect units of its type, the REV2496 powers up with the last preset that was in use before it was switched off. The 400 memory locations are arranged as 200 single-engine effects plus 200 Combi effects, half of each section being presets and the other half available for user programs. In other words, you can write 100 single-engine effects of your own, plus 100 Combi effects. To load a preset, you must first press the Engine A, Engine B, or Combi key to specify which type of algorithm you wish to load and, in the case of the single-engine effects, into which engine it is to be loaded. The dial is then used to run through the programs. Pressing OK/Tap confirms the selection and loads it. Right away the four most important parameters can be tweaked using the four rotary encoders, without the need to enter Edit mode, though if deeper changes are necessary, hitting Edit will put you in the right place.

Once a program has been recalled, the display shows the routing in graphical form, along with the functions of the four knobs beneath. In Edit mode, the display is entirely given over to virtual control knobs (or graphics if you select the graphical mode) and where multiple pages are available these are shown by tabs at the top of the screen. The Page button scrolls through the various screens and where you need to alternate between two parameters in the graphic mode the Edit knob push switch is used to toggle between them. Note, though, that all single-engine edits are based on the current algorithm, so you have to select the required algorithm before starting to edit. When editing Combi effects, the relative contributions of the two engines can be adjusted and, with the exception of the compressor, you can also switch off each engine to, in effect, solo the other.

The REV2496 In Use

Using the REV2496 is largely intuitive, and you only need to visit the manual when editing the more complex algorithms. The on-screen information is very clear and easy to navigate and again reminds me very much of the Behringer DDX3216 digital mixer, which turned out to be particularly user friendly. On a practical note, I still prefer effects boxes to have an input gain knob, but this is by no means the first unit of its kind to dispense with one.

Operating system aside, what really matters with a unit of this type is how well the reverb sounds work in a musical context. As claimed by the designers, the REV2496 does have a very dense, classy reverb sound, particularly when using the V-Verb algorithm, and there's enough editability to suit just about any application without the number of editable parameters getting silly. On the other hand, I don't feel the reverbs have the same depth or complexity as those of something like a Lexicon PCM91, and the ambience algorithms aren't nearly as authentic sounding to my ears. But put the REV2496 up against any mid-priced reverb processor and I think you'll be pleasantly surprised, especially as the REV2496 costs significantly less. It certainly exhibits no serious vices, such as ringing or lack of density.

The Gold Plate algorithm, with its integral bank of delays is also surprisingly versatile — you can use it to create a fair emulation of a classic plate reverb, or to emphasise the delays to create a multi-head tape echo sound with a ice gloss of reverb on the top. Similarly, the delays are first rate, and having a tap-tempo facility for delay time setting, while not unusual, is incredibly useful and time saving. I found the modulation effects to be strong and confident sounding, with particularly nice stereo chorus effects on offer, and the phaser effects were also musical and strong.

Of course it's easy to forget that the REV2496 can also function as two high-quality reverb processors in one, which is an attractive proposition if you want to run a long vocal reverb and a short drum reverb at the same time. On balance, I'd say the rooms, concert halls, and plates show off the greatest strengths of this unit, whereas it handles smaller, more coloured-sounding spaces rather less convincingly. It's not that these smaller space emulations lack quality or smoothness, but I found them rather bland.


It's easy to criticise a unit like this if you put it up alongside a true high-end unit, but the reality is that it manages to deliver surprisingly good-quality reverb for a bargain-basement UK price. It can certainly hold its own against much more expensive competitors, and it could prove attractive to those computer users who don't have enough spare power to run convolution reverb plug-ins. It's also very easy to apply EQ and modulation within the reverb algorithms to fine-tune the patches to your own needs without having to start from scratch, and in many cases the four directly accessible parameters will enable you to get close to the sound you want without you ever having to go into Edit mode at all. And don't forget the dual-channel capability — it's almost like getting two reverb units for the price of one. If you aspire to the best, but don't have the budget, the REV2496 is one of life's better compromises!

Published August 2004