Eos tips and tricks

Eos has been out for a month and a half now, and the reception seems pretty positive. I thought I would share some tricks that came up during the development of the algorithms, as well as some more recent ideas.

  • Gated reverb. The Attack control in Superhall allows you to approximate a gated reverb sounds Set Attack to around 50, Decay to a low value (<1 second), Diffusion to 100, and play around with Size to get the gate time. If the sound is too grainy, turn up Decay a little higher.
  • Reverse reverb. Same settings as above, but set Attack closer to zero.
  • “Shape.” The late 80’s Lexicon reverbs had “Shape” and “Spread” controls to control the initial onset of reverb energy, with high Shape settings resulting in a reverb that fades in slowly. The Superhall Attack control has a similar function, in that the first few hundred milliseconds can have an exponential decay (for high settings of Attack), a relatively flat response (Attack=50) or fade in slowly (Attack=0).
  • Using an external chorus to simulate the EMT-250. I recently heard sound examples of the EMT-250, and that thing had TONS of modulation. In Eos, the Superhall algorithm can get similar levels of modulation right out of the box, but the plate algorithms have a somewhat drier sound for the first few hundred milliseconds. By running a decent chorus or ensemble plugin in front of Eos, and using the Plate 1 or Plate 2 algorithms, you can get a sound that is closer to the EMT-250 (the Plate algorithms are closer in concept to the EMT-250 than Superhall). Set the Low Crossover and High Crossover frequencies at 1000 Hz, set the Size to 30 meters, Mod Freq to 0.5 Hz or so, and Mod Depth at max, and then tweak your chorus until the initial sound is as “wet” as you like. Obviously, this works better on a bus send. The internal modulation of Eos will give you spreading sidebands as the sound decays, that you just can’t get out of a convolution reverb.
  • Ethereal vocals. Use Plate 1 or Plate 2, set the Low Cut frequency to a fairly high value (800 Hz to 1200+ Hz), and the High Cut frequency to a similarly high value (8000 Hz or higher). Set the mix to a fairly subtle level. The fundamental frequencies of the vocals will not be reverberated to a great extent, but the syllabants and consonants will have a fair amount of reverb. This type of sound can be heard all over Simon and Garfunkel albums – I’m not sure if this was due to the 7-story staircase reverb chamber at Columbia studios, or over enunciation of consonants, but it is definitely a good sound for those choirboy things.
  • Emulating older reverbs by backing off on the diffusion. The Superhall algorithm took some of its sonic inspiration from the Lexicon Concert Hall algorithms, but Superhall can have a much higher initial echo density. By turning the Diffusion parameter down to 50% or so, the more “spacious” or “grainy” sound of the older algorithms can be achieved.
  • Longer reverb time. In your host’s default parameter view, move the Low Crossover to a high frequency (>8000 Hz), and set the Low Multiplier to 2.0. This should increase your maximum Decay time to 20 seconds.

If you have any Eos tricks that you would like to share, feel free to post them in the comments.

About the author:

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

Comments (7)

  1. Great tips on the Eos. But I don’t get that last one….When I set the settings for the Low Xover and Mult, should the extra 10 secs Decay time just magically appear or do I just listen for it?

    1. The extra 10 seconds of decay should be audible. It doesn’t show up in the UI as an extension of the main decay time, although the 2x Low Multiplier can be a clue. Using this trick, you lose some of the frequency shaping, but 20 second reverb decay times are usually used for special effects, as opposed to realistic room modeling.

  2. Hi Sean,

    re: emulating the 250, when you say inserting a chorus ‘in front of’ Eos, I take it you mean putting it before Eos, rather than adding a chorus to it’s output?

    Congrats on such a great reverb, btw. I love it.


Leave a Comment

Rules of the Blog

Do not post violating content, tags like bold, italic and underline are allowed that means HTML can be used while commenting.