In order to dial in the desired reverb characteristics while using ValhallaShimmer, it helps to understand how the Feedback, Diffusion, Size, and Reverb Mode parameters work together:

  • The Feedback parameter controls how much of the output signal is fed back into the inputs. If ValhallaShimmer is viewed as a delay line (and it is far more complicated than that, but with Diffusion at zero this is a fair approximation), the Feedback parameter controls the number of repeating echos before the signal decays to inaudibility.
  • The Feedback parameter also directly affects the perceived intensity of the pitch shifted signal when the Pitch Shift mode is not set to bypass. A higher Feedback setting will result in a more intense pitch shifted sound.
  • The Size control changes the overall delay length(s) in ValhallaShimmer. A larger setting of Size will result in longer delay lines, which results in a longer time for the echos generated by the Feedback parameter to decay away.
  • The Diffusion parameter adds echos to the “delay line” at the heart of ValhallaShimmer. The echos increase with each feedback pass through the network, so combining Feedback with Diffusion results in echos building exponentially in density, until the signal is no longer perceived as discrete echos, but as a reverberant decay. Higher settings of Diffusion result in the echo density building up more quickly with a given Feedback setting.
  • The Diffusion parameter can also add its own reverb decay, even without any Feedback being used. If Diffusion is set around 0.9, the result will be a reverb sound that is considerably longer than the delay length would be without any Diffusion. Applying Feedback to this network will result in a much longer reverb than the same Feedback setting with a lower Diffusion setting.
  • The Reverb Mode parameter has a global effect on the lengths of the delay lines, as well as the density of the echos produced by the Diffusion parameter. The larger the Reverb Mode, the longer the delay lines, and the higher the density for a given setting of Diffusion.

Given that the controls have a fair amount of interaction with each other, there is no one method to get a reverb decay of a given length. The user can decide if it is best to use a larger Size in conjunction with a smaller Feedback setting, or to rely on high Diffusion settings and less Feedback, and so on. ValhallaShimmer is meant to encourage exploration on the part of the user!

An example approach:

  • Start with the Reverb Mode parameter. mediumStereo is best for halls and other “kinda” large spaces. bigStereo and mono are huge, and are a good starting point for very long ambiences. smallStereo is best for short ambiences, spring reverbs, and other sounds that are more metallic.
  • Next, set the Diffusion parameter for the desired attack. Low values will start off as echos that slowly build to reverbs, values around 0.5 to 0.618 will cause the reverb to slowly fade in, and values between 0.8 and 0.91 will have a relatively quick attack.
  • The Size parameter can be used to adjust the precise attack time of the reverb, as well as the amount of “color.”
  • Once the attack time is dialed in with Diffusion and Size, use Feedback to get the desired decay time.
  • After this, adjust the tone controls and modulation controls to taste.