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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