Connexions

You are here: Home » Content » Selecting the Effects Levels
Content Actions

Selecting the Effects Levels

Module by: Rob Smith

Summary: This module talks about how the proper effects levels are selected from the provided data.

Once the song has been processed by findChords and beatDetect, the proper effects levels need to selected. The levels are calculated 6 times a second throughout the song using the values returned by the findChords and beatDetect methods.
Beats and Chords Over Song
Beats and Chords.png
Figure 1: This graph holds the beat and chord information for the length of Mixed Phantom and Riff.wav This data is used to calculate the proper effects levels.
This beat and chord data is compared with presets in the program to determine the proper effects levels for each 1/6th of a second chunk of the song. These presets are designed for heavy metal music, but they could be easily adapted for any other music style
Effects Presets
  Fast Playing Slow Playing
Single Notes 100% Distortion, No Reverb 75% Distortion, 40% Reverb
Chords 75% Distortion, No Reverb 60% Distortion, 100% Reverb
Flange is handled differently than the other two effects. Flange is proportionally added whenever the beat count drops below two. If the beat count is zero, the piece will have 100% flange applied.
The effects quantity calculations produce a vector for each effect with values ranging for 0 to 1. A value of 0 means do not apply any effect at all, while 1 means apply the maximum quantity of that effect.
Effect Levels Over Song
Effects Plots 5.png
Figure 2: The quantity of each effect to apply during each section of the song.
These vectors are low pass filtered before the effects are applied to the song. This guarantees a smooth and musical transition between different effects styles, and also prevents any momentary deviations in our detection algorithms from changing the output. In practice, you don't want the effect style changing for every different note you hit, so our low pass filter does an excellent job of melding segments together to create a consistant level of effects for your current overall style of play.
Figure 3: This is the sample file used for the graphs in this article without any effects applied.
Figure 4: This is the sample file used for the graphs in this article with the effets applied by our program.

Comments, questions, feedback, criticisms?

Send feedback