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A Tour of Altiverb

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If I were (and I am not) a gushing computer audio geek, I would probably go all out (on a not-so-very long limb) and say Audio Ease's Altiverb plugin is the best and possibly only reverb plugin anyone could ever need. I would use a lot of clichéd modifiers like 'lush', 'gorgeous' and the omnipresent 'powerful' to describe its sound and functionality, and probably speak on the 'painstaking' or 'intricately detailed' development process. 

 But, I am not a gusher and avoid much of that type of language – yet do find extreme difficulty in doing so here, as Altiverb is simply just that good.

What Is Altiverb?

Altiverb is an ultra-high quality convolution reverb plugin made by the Dutch company Audio Ease. A convolution reverb is a purely digital type of reverb that works by imparting a pre-recorded room response (impulse response, or IR) on a stream of incoming audio. In other words, the room reflections of a specific space are recorded and then imparted onto a piece of digital audio, resulting in the illusion of that audio event occurring in the pre-recorded space.

Main Interface

Altiverb's interface can be broken down into six basic sections. The library section grants access to the extensive and ever growing impulse response library. The main control section contains the more brute force controls, while the secondary control section deals with fine tuning. The visualizer menu dictates what is seen in the two visualizer areas below. This can range from pictures of the recorded room all the way to hidden sound shaping parameters.

The main areas of the interface.

The Library

The Audio Ease team has spent years traveling the world recording the reflections of iconic spaces throughout Europe, Australia and North America (primarily). Clicking on the library area will reveal the fruits of this labor in the form of a detailed and well organized stock library of impulse responses. This library is periodically updated by Audio Ease with free IR downloads.

The library's main page showing the IR's categorized by application and type.

Within each of these categories and sub categories are hundreds of individual impulse responses of everything from stadiums to stairwells to nuclear cooling towers. The music column on the main page consists primarily of spaces where one might expect to hear music being played. The post column is geared towards those working in film and consists of spaces where one would have a conversation or expect to hear everyday ambient sounds. The final column is more geared towards sound design and leaves space for user created IR's as well.

The default setting is actually just one of a multitude of IR's recorded in Berlin's Teldex studio.

The Controls

Anyone who has used a reverb unit before should find the controls pretty straightforward. The main controls to the left deal in the more overarching aspects of the effect while the secondary controls along the bottom serve to fine tune things. Below is a brief rundown.

  • The reverb time knob adjusts the level of the reverb tail, thereby making it shorter or longer.
  • The size knob effects the apparent room size by adjusting a combination of reverb tail length, early reflections, and resonance frequency.
  • The bright knob glues a synthetic higher frequency reverb to the already existing organic IR to create the illusion of a brighter tail.
  • The Input/Output section to the immediate right contains control for input and output level, as well as wet/dry mix control. The disclosure triangle opens up a small menu of test sounds which can be activated and modified to sound whenever a parameter is changed.
  • The EQ is a fairly straightforward two band EQ (clicking the disclosure triangle reveals further parameters) which effects the wet signal only. The EQ bands themselves are Baxandall EQs, which limit phase shift and all but eradicate frequency cancelations when the wet and dry signals are summed.
  • The damping controls shorten or lengthen the IR time according to specific frequency bands. The width of the affected bands can be adjusted in the disclosure menu.
  • To the far right are the Time controls. The pre-delay separates the time between the dry and wet signals and the attack modifies the onset of the wet signal. The disclosure triangle unveils direct, early and late reflection gain controls as well as a reverse button and color and modulation controls.
The interface showing the disclosed parameters.

The Visualizer & Menu

The menu across the top of the interface dictates what is made available in the two visualizers below. I've listed the more unique menu options below.

The pictures option displays the available images related to the selected IR. In the case of the Teldex Studio, there are a few images of the studio, a diagram of the recording setup and a surround picture of the space (similar to what you would find in Google Maps). These different views can be scrolled through and expanded with controls located at the bottom of the visualizer window.

The recording diagram of the Teldex Studio IR.
An image of the Teldex surround picture.

The positioner section reveals a 3D soundstage in which the user can position the input sound source(s) within the virtual room. The speakers can be moved anywhere on the grid and can even be uncoupled to create an asymmetrical stereo field.

The positioner option enabled.

The waveform section is worth noting as it illustrates the four recordings (one of the reasons this plugin sounds so great) which make up the impulse response. In this instance two speakers were used to create the initial sound and two microphones were used to capture the reflections. Each left to right/right to left microphone and speaker combination was recorded and combined to create this particular IR.

The IR waveforms showing the left and right microphone captures of both left and right speakers.

The waterfall, probably Altiverb's most distinguishing visual feature, plots amplitude vs. time vs. frequency of the reflection. This 3D diagram can be moved, rotated and zoomed in on from any angle and is constantly updated to reflect all pertinent parameter changes.

The waterfall from the low side.

The Sound

I've just grabbed a few fairly dry stock loops to test things out. They are all mono (dry and mono tend to go hand in hand) but will serve as a good indicator of just what Altiverb can do. Each recording consists of a dry pass and then one with an Altiverb preset. The only adjustments I made were to the mix ratio.

Playing some guitar in a Nashville studio.

Altiverb does gear too; a house vocal run through the wall sized EMT 140 plate.

The same loop with a similar plate setting in Logic's Space Designer convolution reverb; harsh, digital, thin, etc, etc.

An old school drum loop run through an old school space echo.

If you were ever curious what an upright bass would sound like in an Austrian forest, this is it.

Another Space Designer comparison. No contest.

Funky guitar club verb.

That annoying baby sitting next to you on the plane... put in a metal trash can.

Final Thoughts

In my experience, this is the best reverb out there. It is a joy to work with and produces great results every time with very little tweaking necessary. It has an IR suited for every type of program material and has an extensive library of sound design and post production effects that I barely have had time to touch on.

The one draw back is that it costs $600. Fairly high for a plugin, but a justifiable expense when taken in perspective—cost vs. quality, importance of reverb as an effect, the fact that it makes most other units irrelevant, and it's cheap compared to hardware. I tend towards the school of thought which promotes using only a few high quality pieces of gear well so the price, although still somewhat painful, was one I could live with. 

It may not be for everyone, but I highly recommend consideration towards its purchase if you are looking for a high quality reverb that will remain a prominent and cutting edge tool for years to come.

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