Zul amin L. Manalindo bachelor of science in computer engineering guitar tuner assistant

INTRODUCTION


Significance of the Study

Music has been very popular to everyone. No matter what age people are, music has been in their soul depending on what genre they are going through as long as they love the music, they can groove all the way long, cry through the depths of nostalgic experiences, laugh until they can, over the joy they are committing. In our daily lives, with every step they take, with every situation music can accompany us to satisfy our emotions. Through instruments, they can express our feelings like piano, drums and especially guitar.

Guitar, classified as a six-string instrument, is very popular, especially the acoustic guitar, which is used in various methods of playing music. The main types of modern acoustic guitars are the classical guitar (nylon-string guitar), the steel-string acoustic guitar, and the archop guitar. Vibration is the root of the tone of the guitar strings, which is amplified by the body of the guitar that serves as a resonating tool to produce the sound of every string. The classical guitar is often played as a solo instrument using a comprehensive fingerpicking technique (JMG Pelayo III et. al., 2015).

Guitar players, especially beginners, are getting annoyed with instruments that are out of tune. It may sometimes end up with disappointments to people who want to listen to what they are playing. Advanced guitarists can easily detect whether the guitar is out of tune or not. Most probably they tune their instrument manually, from this generation there are assisting devices to help them tune their guitar. There are tuners that can be attached and can be bought in some musical stores, some tuners are already built-in the body of the guitar, and there are also open-source and downloadable guitar tuning application software on our smartphones if they cannot afford buying commercially-available tuners. But even if they have any of these tuners they are still tuning the guitar manually. They are still struggling on how to tune it. It really consumes a lot of time and that will cause us to be impatient, causing us not to get the correct tune.

Objectives of the Study

Generally, the study aims to develop and evaluate a guitar tuning assistant device.

Specifically, the study aims to:

1. 
   develop a device that automatically tunes a guitar; and
   
2. 
   measure the accuracy and precision of the guitar tuning assistant device using an android-based tuning application software as a reference.
   

Scope and Limitations of the Study

The study is limited only to the development and evaluation of the device.

The device will have the following features:

1. 
   The device can match the sound frequency through each string of the guitar;
   
2. 
   The device uses android-based tuning application software as a reference.
   
3. 
   The device is intended for standard tuning.
   

The device has the following limitations:

1. 
   Not intended for non-standard guitars and those guitars with nylon strings.
   
2. 
   Not intended for tuning pitches other than the standard string pitches as E, A, D, G, B, and E.
   

Place and Time of the Study

The design and development of the device will be at Kabacan, Cotabato on December 2020 to January 2021. The study will be evaluated in the same place on February 2021.

Definitions of Terms

The following terms are defined based on their uses and purpose in the study.

Guitar is a six stringed instrument commonly played by many people.

Guitar Tuner is a device that is used to tune the guitar.

Android-based tuning app is an open-source android app used as a reference.

Tuning peg is the part of the guitar that is used for tuning.

String is a steel-wire (some are covered with copper) attached to the guitar that produces the sound when plucked or strummed.

Predefined range of frequencies are used to determine the pitches of the notes from low to high, 82.4, 110.0, 146.0, 196.0, 246.9, 329.6 Hz respectively.

Conceptual Framework
Figure 1 below shows the problem, solution and the results that will be considered in the study.

Problem		Solution			Results
Manual tuning for guitar Difficult for beginners to tune the guitar Manual tuning is based on human sensitivities which may lead to inconsistencies or inaccuracies		Development of the Guitar Tuner Assistant		Automatic tuning for guitar Easier for beginners to tune the guitar A new device that tunes guitar consistently and accurately

Fig. 1. Conceptual framework

REVIEW OF LITERATURE


Guitar as Preferred Musical Instrumental by Jose Maria G. Pelayo,

Shedy Dee C. Mallari, and Jose Juancho S. Pelayo

The Guitar is an extremely famous instrument that is normally utilized by numerous artists. This investigation concentrated on the components that made the guitar all the more engaging the young in contrast with different instruments. A semi organized, open finished poll was utilized to gather the information fundamental among selected students. This study focused on the factors that made the guitar more appealing to the youth in comparison to other instruments.

Vibration is the root of the tone of the guitar strings, which is amplified by the body of the guitar that serves as a resonating tool to produce the sound of every string. The main type of guitars mentioned by Pelayo et al., as the modern guitars are the classical guitar (nylon-string guitar), the steel-string acoustic guitar, and the archtop guitar. The classical guitar has been usually played as a solo instrument using a comprehensive fingerpicking technique.

A Digital Guitar Tuner by M. Regeena and A.K. Saji

Tuning with just hearing without any device is very handy. If you are not an amateur musician you can’t have the exact note. It was just playing a guessing game in which you tune what you think is right but isn’t. According to Mary Regeena, 2009, who studied about guitar, that note is not made of a single frequency. It consists of a number of harmonics as well. She said that the human ear is insensitive to variations of frequency smaller than +/- 0.5 Hz. This results in a limitation that has to be overcome in recovering the fundamental frequency from the frequency range of the sample note played on a guitar. When obtaining the real-time data, the sampling interval must be kept at a minimum level, however, this will reduce the resolution of the spectrum and therefore affects the accuracy of frequency estimation. Regeena suggested few solutions to overcome the said problem. One method she used in her study is to increase the resolution of the spectrum to achieve accurate estimation of the frequency of the signal. Another method is to increase the duration of sampling to increase the frequency resolution of the Fast Fourier transform.

The emphasis of this design lies in developing a suitable algorithm to accurately detect the fundamental frequency of a plucked string from its frequency spectrum. With a single struck on a string the frequency is being recorded. A single musical note is very crucial when it comes to tuning, unwanted frequencies that come from any other noises nearby are being eliminated to prioritize the desired frequency. With every frequency recorded, computers convert every signal into discrete values and are plotted in their own discrete positions equally spaced known as bins. The smaller the bins the more accurate the signal will be. Detecting and filtering the frequency of each string are the most common ways of this study when computing the actual frequency of each note.

Acoustic Guitar Tuner and Identification of Chords using LabVIEW

by Swagat Sourav, S. Balamurugan, Marimuthu R., Sudha

Ramasamy, and A. Bagubali

With the help of notes and octaves an audio from the guitar itself can be captured through a built-in microphone on a computer and has been designed in LabVIEW 2010. These real time notes are converted into signals to be given as an input to the guitar tuner program which can be processed. Outputs are shown through LED lights whether the string has the right note. It has three LEDs that give information to the user: Left (string has been lower than the right tune), middle (perfectly tuned), and right (string has been higher than the right tune).

When playing a guitar, it is very usual on whatever style you want to, you can play with a pick or with your own fingers to pluck the strings. Every time a string is plucked a note is produced, and every note variations of pitch will determine if the string is on tune or not.

A normal guitar has 6 strings, there are types of guitar which can also be played the same way as this ordinary guitar. There are Bass guitars, electric guitar, Classical guitar, and the acoustic guitar. Each string of this instrument has their own pitches from low to high and are classified as E, A, D, G, B, and e. These pitches also have their frequencies from low to high 82.4, 110.0, 146, 196, 246.9, 329.6 Hz respectively.

Notes are signs used in musical notation to represent the relative duration and pitch of a sound and the pitched sound itself may also refer to as a note. There are seven notes as recognized in the field of music A, B, C, D, E, F, and G. When simultaneous pitches are played, they can produce a chord which consists of two or more notes played together. There are also these so-called Octaves which is known as the interval between one musical pitch and another with half or double its frequency. Basically, these are the sharps (♯) and the flats (♭).

Guitar Chords Classification Using Uncertainty Measurements of Frequency Bins by Jesus Guerrero - Turrubiates, Sergio Ledesma,

Sheila Gonzales – Reyna, and Gabriel Avina – Cervantes

When playing the guitar, you can simply pluck every single note you want. And when you play multiple notes simultaneously you can form a chord, but of course it may be formed by a harmonic set of two or more musical notes. These notes may be referred to as C, C♯/D♭, D, D♯/E♭, E, F, F♯, G, G♯/A♭, A, A♯/B♭, B. The interval between notes is called as half-note interval or semitone interval. Thus, chords can be seen as musical features and they are the principal harmonic content that forms a musical piece.

A harmony has an essential development known as triad, in music, a chord made up of three tones, called chord factors, of the diatonic scale: root, third, and fifth. The root can be any note looked over the pitch class set, and it is utilized as the main note to build the harmony; moreover, this note gives the name to the harmony.

In order to perform chord recognition, two matching methods were tested: The Nearest Neighbors (Euclidean distances between the template vectors and the chroma vectors) and the Weighted Sum Method (dot product between the chroma vectors and templates). This method classifies chords from any octave for a six-string standard guitar. The chord types are major, minor, major 7^th, and minor 7^th, that is, the same variants for the chords used by Barbancho et al.

Proguitar – Guitar Tuner

Proguitar, as shown in Fig. 2, is a Guitar Tuner which tells you with professional accuracy, on the cent, if your instrument is in tune or not. You can use the tuner made by ProGuitar to tune other instruments than a 6-string guitar. This app is available for Android and also for IOS devices. Many other guitar tuners will only show you the standard tuning, that is; E, A, D, G, B, e. These tuners may also just look for pitches in a certain range corresponding to each string and might not notice if you play a too high or low pitch. What you can see in the interface of the app shown in the figure are (1) the cents for the current pitch, (2) a red/green light indicating the closest current pitch, (3) a note wheel corresponding to the chromatic scale, and (4) a fretboard with the current tuning setting displayed.

Fig. 2. Proguitar interface

With this app, the user cannot only tune guitar but also any other stringed instrument like bass, violin, ukulele, banjo, mandolin family, and others. These instruments have specific number of strings, for example guitar has only six strings, while violin, ukulele, and bass have 4 strings.

In the settings panel you can choose a reference frequency between 415 Hz and 467 Hz. “A4” as in 440 Hz is the standard reference frequency because this is the most common reference for modern music.

METHODOLOGY

This chapter will be presenting the materials and methods used in conducting the study.

Materials

Acoustic Guitar, as shown in Fig. 3, is the playing instrument that will be used in producing sound.


Fig. 3. Acoustic guitar
Motor, as shown in Fig. 4, is a machine that will be used for turning the tuning peg either clockwise/counter-clockwise.

Fig. 4. Motor

Android Phone, with a standard tuning app installed as shown in Fig. 5, will serve as the reference when tuning the instrument.

Fig. 5. Android phone

Arduino, as shown in Fig. 6, will serve as a microprocessor of the device.

Fig. 6. Arduino

Power Supply, as shown in Fig. 7, will be used as a power source of the device.

Fig. 7. Power supply

Push Button Switch, as shown in Fig.8, a switch to turn on the device.

Fig. 8. Push button switch

Jumper Wires, as shown in Fig. 9, a set of wire that connects the circuit components of the device.

Fig. 9. Assorted jumper wires

Sound Sensor, as shown in Fig. 10, a device that will detect the sound signal from the guitar which in turn be fed onto the microcontroller.

Fig. 10. Sound sensor module

Device Analysis

The diagram in Fig. 11 shows that while the guitar user plucks the guitar strings that produces sound, the device within the predefined range of sound, senses the strings’ frequencies through sound sensor, and it will be fed to the microcontroller via its program, so that each designated motor could turn the tuning pegs attached to it into its correct rotation direction. The rotation or adjustment will be done in slow pace as the user continuously plucks the guitar strings until it matches the right frequency. During the evaluation of the device, the string sound produced by the newly adjusted guitar will be subjected for testing with the help of a guitar tuner app, which will help the researcher validate the results.

Input			Process				Output
Sound Sensor			Microcontroller				Motor/ LEDs
Fig. 11. Block diagram of Guitar Tuner Assistant

Development of the Device

The Development of the device, composed of three parts, namely, input, process and output. The program will be coded in Java through Arduino to be loaded in the microcontroller.

The flow of the function of the device as shown in Fig.12 is listed below in sequential details:

1. 
   Start the device by turning on its power. The device initiates its program and prepare the guitar for tuning.
   
2. 
   As soon as the user starts plucking the strings, the device senses the string position that was plucked by the user based on what sound frequency range it belongs;
   
3. 
   If the produced frequency matches with any of the predefined frequencies range, an LED will turn on indicating a match. The device will now decide the turning direction of the motorized peg. If the frequency is greater than the ideal frequency string (preset), the motorized peg will turn in clockwise direction bit-by-bit. The user should continually pluck the same string while it is turning. However, when the frequency is less than the ideal frequency string (preset), the motorized peg will turn in counter-clockwise direction bit-by-bit.
   
4. 
   The motorized peg will only stop turning when it finally matches to its ideal frequency. This process goes the same with the rest of the strings of the guitar.
   

Fig. 12. System Flowchart

Research Design

This study will be using descriptive research design to analyze and evaluate the device in terms of accuracy in tuning each string of the guitar with the assistance of a tuning app running in an android-based device.

Data Gathering Procedure

In gathering data, five trials are going to be performed when tuning each string (E, A, D, G, B, e) according to their frequency as shown in Dummy Table 1. All strings will be untuned and be tuned again to measure it’s accuracy by scale for each trial. The data will be recorded and analyzed which will be used as the basis in establishing the results of the study.

Dummy Table 1. Dummy table for tuning using an Android App (denoted by “A”), and the new device (denoted by “ND”).

STRING

TRIALS

1

2

3

4

5

A

ND

A

ND

A

ND

A

ND

A

ND

E

A

D

G

B

e

*A – Android App

*ND – New Device

Statistical Analysis
The data to be gathered will be analyzed and interpreted through the use of T-test.

LITERATURE CITED
Jesus Guerrero - Turrubiates, Sergio Ledesma, Sheila Gonzales – Reyna, and Gabriel Avina – Cervantes, 2015. Guitar Chords Classification Using Uncertainty Measurements of Frequency Bins
Jose Maria G. Pelayo, Shedy Dee C. Mallari, and Jose Juancho S. Pelayo, 2015. Guitar as the Preferred Musical Instrument
M. Regeena and A.K. Saji, 2009. A Digital Guitar Tuner
Proguitar, https://www.proguitar.com/guitar-tuner
Swagat Sourav, S. Balamurugan, Marimuthu R., Sudha Ramasamy, and A. Bagubali, 2016. Acoustic Guitar Tuner and Identification of Chords using LabVIEW




APPENDICES

DECEMBER 2020