Pop Punk Equalizer

By: Nick Parisi

Overview

• Introduction to Flanging• Initial Design• Design of Filters• Design of Flanging in Simulink• GUI Features• Demonstration

Flanging• An audio effect, that creates a “whooshing”

sound known as the Darth Vader effect• Adds a time-delayed copy of itself onto the

original signal

How is Flanging Created?

• When you mix two identical signals together– Signal 1: unaltered audio signal– Signal 2: signal delayed by a small period

• Creates peaks and notches in frequency spectrum

• Signals get too close it sounds like “sucking air”

• Larger the signal the more noticeable the effect is

Initial Design

• Used fdatool to make biquad filter– Exported to simulink

• Sound came out terrible

DesignUsed the DSP System ToolBox to design– One low pass filter– 13 bandpass filters– One highpass filter– 16 gain blocks

• Bass– First six filters

• Mid– First four filters

• Tremble– Last five filters

Filters

BandPass Filter Selection• The 2/3 octave for 15 bands needs a Q value of

2.14• Formula used for the lower cutoff frequency

-Formula used for the lower cutoff frequency

-Designed to be IIR Chebyshev II-Did not want ripples in the passband

Design- Flange• Makes a copy of the signal – The copy is then delayed

• Flange is activated by a switch– That switch can be activated by a push button

GUI

Special Features- Song Selection/Albums• User can pick between four songs• Songs are stored in a pop-up menu• Only one song is used in the Simulink model• Case statement used to play different songs

Special Feature- Mute Button• Mute button is activated by a switch• Activated in the GUI by a toggle button

Future Work

• Create a slider to vary the flanging on the song • Faster Switching between songs• Have more album artwork appear depending

on the song playing• Have a suggestion box appear based off what

song is playing• Having the song turn off when the user exits

the out of GUI

References

• http://www.sengpielaudio.com/calculator-cutoffFrequencies.htm

• http://en.wikipedia.org/wiki/Flanging