syed syahril traditional musical instrument simulator for guitar1

SYED SYAHRIL TRADITIONAL MUSICAL INSTRUMENT SIMULATOR FOR GUITAR 1


OVERVIEW

• Motivations & Objectives• Development Tools• Digital Audio Effects• Target Traditional Instrument Analysis• Model Explanations• Results & Discussions• Conclusion & Recommendations


MOTIVATIONS

• Difficulties in obtaining most of traditional musical instruments

• Time consumption on learning new methods of playing traditional instruments

• Limitations of notes produced on certain traditional musical instruments

• Availabilities of western musical instruments simulators


OBJECTIVE

• Develop a program that simulates a traditional musical instrument (Kecapi) by using an easily accessible instrument (Electric Guitar)


• One of the most common music instrument• String type which is suitable for string type

traditional ones

TOOLS - Guitar


• Indonesian traditional music instrument• Sound produced by the sound hole

TOOLS - Kecapi


Guitar vs Kecapi

Comparison on notes produced


• Transducer – Air pressure to electrical signals• Used in recording Kecapi sound• Microphone are selected based on :

– Frequency response– Frequency range

• Shure SM57 are selected due to its balance on both specifications stated above as well as the cost

TOOLS – Microphone


TOOLS – Microphone (Comparison)Common House Microphone

Shure SM62

Shure SM57


TOOLS - Simulink• MATLAB add-on• Graphical environment in developing simulations• Based on flow of signal trough various type of blocks

Signal flow lines

Simulink BlocksetRunning simulation


TOOLS - Simulink

From Wave Filespeech_dft.wav

(22050Hz/1Ch/16b)

From WaveFile

z-f

In

DelayOut

VariableFractional Delay

Constant

130

DSP

Sine Wave

name.wav

To WaveFile

To WaveDevice

FDATool

DigitalFilter Design

z-6900

Integer Delay1

1

Gain

Sum

Tools used in developing the model


TOOLS – Wavelab 5

Audio recording & editing software used in editing recorded kecapi sound


DIGITAL AUDIO EFFECTS - Equalizer• Equalization (EQ) is the process of boosting or

cutting certain frequency components of a signal. • By applying some filters, audio signal of the

source will be equalized to a desired output

1

Out1FDATool

Filter 2

FDATool

Filter 11

In1


• Product of more than one source playing a same sound in unison

• The imperfection of the combination causes chorus effect

DIGITAL AUDIO EFFECTS – Chorus 1


Parameters in configuring a chorus effect :• Sweep Depth• Number of voices• Delay• Rate


Rate


The number of voices is simply the number of delayed signal added to the output



• Reverberation is the result of the many reflections of a sound that occurs in a room

• Reflected sound is a minimally delayed signal of the source

• Reverberation also occur in a sound box of an instrument

DIGITAL AUDIO EFFECTS - Reverberation


MODELING PROCESS

Two main parts :• Analyzing target instrument (Kecapi)

– Time domain– Frequency domain– Auditory

• Synthesizing the effect model (Simulink)– Applying analysis results– Configuring Simulink block parameters


TARGET INSTRUMENT ANALYSIS 1Time domain analysis

•Envelope fluctuates in kecapi

•Chorus effect are suggested to occur

•Similar string notes resonates each other

•Trough listening, the ‘watery’ sound normally caused by a chorus effect

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am

plit

ude k

ecapi

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uitar

Kecapi and electric guitar plot in time domain


TARGET INSTRUMENT ANALYSIS 2

0 1000 2000 3000 4000 5000 6000 7000 80000

20

40

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100

frequency,Hz

dB (

keca

pi)

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frequency,Hz

dB (

guita

r)

Frequency Domain Plot •Frequency domain analysis

•Kecapi contains more high frequency components

•Fundamental frequency of the note is lower in amplitude in a guitar

•A combination of filters is needed in order to equalize the electric guitar frequencies


MAIN MODEL• Simulation model developed based on analysis• Human auditory system is most important tool in the overall design of

the model• Main components : Equalizer, Chorus & Reverberation• Additional gain used to increase the volume of the manipulated signals

In1Out1

chorussubsystem

sample.wav

To WaveFile

To WaveDevice

In1Out1

ReverberationSubsystem

4

Gain2

3

Gain1

From Wave Filesample.wav

From WaveFile

In1Out1

EqualizerSubsystem

FDATool

Bypass Filter


SUBSYSTEM – Equalizer 1• Why ? To equalize the electric guitar frequency components to a

kecapi• Where ? Earlier part of the model to replicate the source (strings)• How ? A low-pass

and a high-pass filter

1

Out1

FDATool

Low Pass

FDATool

High Pass

1

Gain1

3

Gain

1

In1


• Low-pass filter with a cut off frequency of 2kHz

• Actually a band pass filter with a band pass frequency of 10Hz to 90Hz

• Not able to get a flat response for these values

SUBSYSTEM – Equalizer 2


SUBSYSTEM – Bypass Filter• How? - High-pass filter with cut off frequency of 2kHz• Where ? - Certain frequency components of the signal will bypass

the chorus subsystem• Why? - Higher frequency notes has slight chorus effect• Thinner strings which produces high frequency sound has less

effects on thicker strings of the same note (resonance)


SUBSYSTEM – Chorus 1• How? – three variably delayed signals (voice) with different delay

variables (chorus parameters)• Where? – After filters equalized the signal• Why? – Similar note strings

resonates each other• Voice gain values determines

its volume• Three voice chorus selected

since there is three similar string notes excluding theplayed string

1

Out1

z-f

In

DelayOut

VariableFractional Delay2

z-f

In

DelayOut


z-f

In

DelayOut


DSP

Sine Wave2

DSP

Sine Wave1

DSP

Sine Wave

.6

Gain3

1

Gain2

.7

Gain1

1

Gain

130

130

130

1

In1


SUBSYSTEM – Chorus 2

1

Out1

z-f

In

DelayOut


z-f

In

DelayOut


z-f

In

DelayOut


DSP

Sine Wave2

DSP

Sine Wave1

DSP

Sine Wave

.6

Gain3

1

Gain2

.7

Gain1

1

Gain

130

130

130

1

In1

Rate

• Sine wave generator used as a Low frequency oscillator (LFO)

• Every voice has different amplitudes and frequency (Rate)


SUBSYSTEM - Reverberation• How? – constantly delayed signal added to the original signal• Where? – final part of the model• Why? – Reflections of the sound wave in the sound hole of the

kecapi• Number of voices are

are three due to the same reason as chorus

1

Out1

z-7100

Integer Delay2

z-6900

Integer Delay1

z-7700

Integer Delay

.5

Feedback Gain2

.6

Feedback Gain1

.6

Feedback Gain

.7

Delay Mix3

.5

Delay Mix2

.5

Delay Mix1

.4

Delay Mix1

In1


RESULTS & DISCUSSIONS

• The system is able to fairly produce the desired results

• Hearing the resultant audio sound is the best way of concluding the results

• Frequency & time domain plot comparison also referred as a benchmark for the results


COMPARISON – Time Domain• Envelope fluctuations are visible but not as smooth as the original

kecapi sound• Kecapi produces chorus and reverberation effects naturally (wood,

hollow body design). Where the system developed relies on digital signal processing

• Enhance filters, chorus & reverb parameters.• Use 24-bit in processing audio (high resolution, less quantization error)

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itude

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itude

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seconds,time

ampl

itude

Guitar Model Output Kecapi


COMPARISON – Frequency Domain• Model output shows

significant gain in higher frequencies of the guitar signal

• Noise introduced in the output

• The use of compressor in recording a guitar signal reduce the gain amount needed in the higher frequencies

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frequency,HzdB

(guitar)

0 1000 2000 3000 4000 5000 6000 7000 80000

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frequency,Hz

dB

(guitar)

0 1000 2000 3000 4000 5000 6000 7000 80000

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frequency,Hz

dB

(kecapi)

Guitar

Model Output

Kecapi


COMPARISON – Real Audio

• Compares the sound of 3 sources of sound; electric guitar, kecapi as well as model output

• Sample of a similar single note by each source• Sample of a short music produce by these

sources


CONCLUSIONS

• In conclusion, the objectives stated in this project has been achieved by referring to the results obtained

• The usage of effects included in the model gives a good result but has plenty of room to improvise mainly in terms of its parameters and tools used

• With this achievement, traditional music may be easily produced and creatively expands a traditional musical instrument usage


RECOMMENDATIONS

• Further develop a model to simulate other traditional instruments especially string instruments

• Compile as a stand alone program rather than running it in Simulink

• Realize certain amount of traditional instruments simulation onto a DSP board

• Improve tools quality to produce better results

syed syahril traditional musical instrument simulator for guitar1

Documents

rate slide

model slide

simulation slide

guitar1 slide

cost tools microphone

recorded kecapi sound

desired output slide

audio signal