project Guitar Effects Joshua Rock Star Jenkins Jeff Tremolo Smith Jairo the boss Rojas Table of contents Typical Guitar Effects Pipeline Classifying Effects for guitar implementation ID: 426075
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Project V – Digital Signal Processing System Design Final project Guitar Effects
Joshua “Rock Star” Jenkins
Jeff “Tremolo” Smith
Jairo
“the boss” RojasSlide2
Table of contents
Typical Guitar Effects Pipeline.
Classifying Effects for guitar implementation.
Theory of the Effects.
Design Process.
Learning Lessons relating to the class.
Conclusion.
Time for questions (1 only).
Live Demonstration by Josh ($5 per group).Slide3
Typical Guitar Effects Pipeline
This is a layout of the common standard guitar pedal effects processes as shown below such as;Slide4
Classifying Effects for guitar implementation
Audio effects can be classified by the way do their processing:
We will have a Master channel control to regulate these effects.
Equalizer – Treble, Midrange, Bass, Volume.
Non-linear Processing — Fuzz.Delays — Flanger, Reverb, Digital delay.Modulators — Ring modulation, Tremolo.Slide5
Theory of the Effects (Equalizer)
The equalizer is normally use to adjust the sound quality of a song or music instrument whether in a mono or stereo system.
Treble
.
Bass
.
Midrange.Slide6
Non-linear Processing
Non-linear Processors can generate harmonic and inharmonic frequency components not present in the original signal.
Dynamic Processing.
Intentional non-linear harmonic processing.
Exciters/Enhancers.Slide7
Fuzz Effect
A non-linear function harsher alteration of the original sound
than
distortion. Fuzz and distortion can be represented by the formula;
The representation above is a non-linear exponential function:
The gain (
α) controls level of distortion/fuzz.Combined to the mix part of the distorted signal with original signal for output.Slide8
Fuzz Effect block diagramSlide9
Comb Filter Delay Effects:Flanger, Chorus, Slapback
, Echo
Many
useful audio effects can be implemented using a
delay structure.
Basic
delay structures out of some very basic FIR and IIR filters comb filters.Combination of FIR and IIR gives the Universal Comb
Filter
These popular guitar effects can be implemented with a comb filter (FIR or IIR) and some modulation effects.
Flanger, Chorus,
Slapback
, Echo are same basic approach but different sound outputs:Slide10
IIR Comb Filter
Simulates a single delay and endless
reflections at both ends of
cylinder y(n
) to input, x(n
).The input signal circulates in delay line (delay time τ) that is fed back to the input.Each time it is fed back it is attenuated by g
.Input sometimes scaled by C to compensate for high amplification of the structure.It’s represented by the formula:The transfer function is:Slide11
Flanger Effect
The
F
langer effect utilizes continuously
varying
Low Frequency Oscillator (LFO) of delay.
The signal rises and falls in a regular, periodic way. It is produced by mixing two identical signals together.
Works similarly
as the Chorus effect,
however,
it uses a significantly shorter delay time. Slide12
Reverberation (Reverb) Effect
Reverb is consider one of the most heavily used effects in music.
A reflected sound wave like this will arrive a little later than
the direct sound.
This effect is typically use in very big rooms like concert halls and cathedrals. Slide13
Digital Delay
D
iscrete
element in
digital filter
theory, which allows a signal
to be delayed by a number of samples.If the delay is an integer multiple of samples digital delay lines are often implemented as circular buffers.
The
delay by one sample
is
notated
and delays
of
samples
is
notated
by
the role the
z-transform plays
in describing
digital filter
structures.Slide14
Modulation
Modulation is the process where parameters of a sinusoidal signal (amplitude, frequency and phase) are modified or varied by an audio signal.
The types of modulation implemented for our project are;
Amplitude Modulation — Tremolo
Phase Modulation — FlangerSlide15
Ring Modulation (RM)
Signal-processing
effect in electronics, an implementation
of amplitude modulation or
frequency mixing, performed by multiplying two
signals.very simple to implement digitally:For example a sine wave with frequency (fx) we compute the DSB: fc + fx and fc - fx.
A input is periodic with at a fundamental frequency (
fo
), then a spectrum with amplitude lines at frequencies |
kfo
± fc|Slide16
Ring Modulation and Tremolo block diagramsSlide17
Amplitude Modulation (AM)
Can be best defined by:
Normalize the peak amplitude of m(n) to 1.
α
is depth of modulation
α
= 1 gives maximum modulationα = 0 turns off modulationx(n) is the audio carrier signal.m(n) is a low-frequency oscillator modulator.When x(n) and m(n) both sine waves with frequencies (fc) and (fx) respectively we hear three frequencies: carrier, difference and sum: fc, fc - fx
,
fc + fx.Slide18
Tremolo Effect
Tremolo
describes
various
trembling effects
, falling roughly into two types. The first is a rapid reiteration of a single note.A second type of tremolo is a variation in amplitude;
U
sing
electronic effects in guitar
amplifiers
and effects pedals which rapidly turn the volume of a signal up and
down.
Modulates
the amplitude of the incoming signal, resulting in periodic volume changes
. Slide19
Design Process
We incorporated
our knowledge of what we have learned from the assignments in
class from filters and audio effects
.
We designed our project in Labview using Matlab script as well.We implemented one effect at the time and then we combined them together.We will utilize myDAQ to demonstrate the project in real time.Slide20
Design ProcessSlide21
Testing the DesignSlide22
Learning Lessons relating to the class.
Basic
theory and applications of modern digital signal
processing.
Basic theory
of real-time digital signal processing.
Develop ability to implement and simulate digital signal processing algorithms using Labview and Matlab on real-time DSP
platform.
Analog to Digital
implementation and simulation using myDAQ.
How to work as a team to make this project successful. Slide23
Conclusion
Understanding
basic concepts of
digital signal processing guitar effects theories
and
techniques.Understanding of real-time digital signal
processing.Ability to implement digital signal processing guitar effects in Matlab and LabVIEW.
Ability
to implement
analog to digital
signal
processing
on real-time DSP
platform with myDAQ.Slide24
Preguntas