ValhallaRoom: The Reverb Modes

One of the key features of ValhallaRoom is that it is not based around a single reverberation algorithm. Instead, 4 different algorithms are provided, each with their own distinctive sonic characteristics. The algorithms are selected by the REVERB MODE combo box. A quick description of the 4 modes:

  • Large Room. This algorithm was designed to be the most “natural” of the 4 reverberation algorithms. Initially, the decay is a bit sparse, but it quickly builds to a high reflection density. The Large Room algorithm has a very exponential decay, with precise control over the frequency balance of the decay over time. There is a slight amount of high frequency absorption that is inherent to the Large Room algorithm, which reflects the effects of air on high frequencies. The modulation in the Large Room algorithm is designed to create a wide stereo image, but without causing random pitch shifts in the decay. Use of higher modulation depths will result in a “deeper” sound that still retains the original pitch of the input, while shallower modulation depths are useful in obtaining a natural sounding decay.
  • Medium Room. This algorithm emulates a room with walls that are somewhat wider than Large Room – more of a “square” geometry as opposed to the “shoebox” reflection patterns of Large Room. The initial echo density is the sparsest of the 4 algorithms, and audible echos can be heard at the largest settings of Late Size. This also results in a wide stereo spread, and can be useful for certain sounds. The modulation is more random than Large Room, and can cause some random pitch shifts for long decays – which is also a characteristic of many of the “classic” reverb algorithms as found in the early Lexicon boxes.
  • Bright Room: This algorithm has a slightly slower attack time than the other reverberation algorithm. This slow attack time is a characteristic of larger halls, but can also be heard in some of the “classic” digital reverbs, as well as in ValhallaShimmer (although the attack time of Bright Room is much faster than the attack times of the ValhallaShimmer algorithms). The decay of the Bright Room algorithm has more high frequency “air” and “sheen” than the other algorithms – it is fair to say that Bright Room is more “digital” than the other algorithms, in a good way. The modulation in Bright Room is random, complex, and deep, with the goal to provide lush chorusing to any input signal. At some settings, it can sound close to string ensembles, and for long decays, it turns static input sounds into evolving pads. Bright Room is the algorithm I would initially turn to for emulating those Vangelis “Blade Runner” reverbs.
  • Large Chamber: This algorithm shares many characteristics with Large Room, but has a much more “even” early echo density. Instead of emulating the initial echo sparseness of most rooms, it starts off with a very high echo density, similar to the high echo densities found in echo chambers and similar spaces (I’ve spent a lot of time clapping my hands in multi-story concrete stairwells and listening to the decay). The goal with Large Chamber was to get a sound that was “larger than life,” with the echo density of a small space, but the modal density of a large hall. The result is a fairly “colorless” reverb that suits a wide variety of input sounds, and can be used to emulate chambers, rooms, halls, what have you, without imparting a specific “space” on the sounds. You hear the decay, not the walls. The modulation and decay time are similar to Large Room, with the difference that the initial “detuning” of the decay is far more diffuse than the Large Room algorithm.

About the author:

Sean Costello is the "algorithmic reverb plugin wizard" [citation needed] at Valhalla DSP.


  1. Your best product yet. I A/Bed this with my Lexicon PCM Native bundle and Altiverb and I’ve liked it better in every setting I tried. I’m recommending it to all of my friends, pros and beginners. “Buy this right now!”

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