Design And Construction Of A 4-Channel Audio Mixer

An audio mixer is an electronic device for combining, and modifying audio signals. The modified audio signals are summed to produce some combined output signals. This project is titled design and construction of a 4-channel microphone mixer. A microphone mixer is an electronic console that is used to mix different recorded tracks by changing their volume levels, adding effects and changing the timbre of each instrument on the tracks. Audio mixers are also called mixing consoles and soundboards. Mixers are most often used by recording studios but are also typically used in live situations by live sound engineers.

There are two types of mixers, digital and analog, and both are commonly used by the same recording studio to achieve different results.In this work, an analog audio mixer using common electronics components, such as resistors, capacitors, potentiometers and operational amplifiers (Op-Amps).

The aim of this work is to design and construct a 4-channel mixer which can accept four different audio input at the same time and mix their different tracks by changing their volume levels, adding effects and changing the timbre of each instrument on the tracks.

CHAPTER ONE

1.1 INTRODUCTION

1.2 BACKGROUND OF THE STUDY PROJECT

1.3 STATEMENT OF THE PROBLEM

1.4 RESEARCH OBJECTIVE /AIM

1.5 LIMITATION SCOPE OF PROJECT

CHAPTER TWO

2.0 LITERATURE REVIEW

2.1 A BRIEF ONLINE OF THE CHAPTER

2.2 HISTORICAL BACKGROUND OF THE PROJECT STUDY

2.3 THEORIES CONCEPT RELEVANT TO THE RESEARCH

CHAPTER THREE

3.0 RESEARCH METHODOLOGY

3.1 A BRIEF OUTLINE OF THE CHAPTER

3.2 RESEARCH DESIGN

3.3 BLOCK BY BLOCK

CHAPTER FOUR

4.0 PRINCIPLE OF OPERATION OF PROJECT

4.1 BRIEF INTRODUCTION OF THE CHAPTER

4.2 PRINCIPLE OF OPERATION OF THE PROJECT (FOR CASE STUDIES )

4.3 EXPLANATION OF THE VARIOUS UNITS BLOCK IN THE PROJECT (FOR CASE STUDIES )

CHAPTER FIVE

5.0 CONSTRUCTION OF THE DESIGNED PROJECT

5.1 A BRIEF OUTLINE OF THE CHAPTER

5.2 CHOICE OF MATERIALS

5.3 CONSTRUCTION OF THE PROJECT

5.4 BEME TABLE (FOR CASE STUDIES )

5.5 TEST RESULT OF TESTS

CHAPTER SIX

6.0 CONCLUSION SUMMARY AND/OR RECOMMENDATION

6.1 SUMMARY OF THE STUDY PROJECT CHAPTER BY CHAPTER

6.2 PROBLEM ENCOUNTERED

6.3 RECOMMENDATION

6.4 SUGGESTION FOR FURTHER STUDIES

ABSTRACT

An audio mixer is an electronic device for combining, and modifying audio signals. The modified audio signals are summed to produce some combined output signals. This project is titled design and construction of a 4-channel microphone mixer. A microphone mixer is an electronic console that is used to mix different recorded tracks by changing their volume levels, adding effects and changing the timbre of each instrument on the tracks. Audio mixers are also called mixing consoles and soundboards. Mixers are most often used by recording studios but are also typically used in live situations by live sound engineers.

There are two types of mixers, digital and analog, and both are commonly used by the same recording studio to achieve different results.

In this work, an analog audio mixer using common electronics components, such as resistors, capacitors, potentiometers and operational amplifiers (Op-Amps).

The aim of this work is to design and construct a 4-channel mixer which can accept four different audio input at the same time and mix their different tracks by changing their volume levels, adding effects and changing the timbre of each instrument on the tracks.

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                               BACKGROUND OF THE STUDY PROJECT

Audio mixer is an electronic device for combining (also called “mixing”), routing, and changing the level, timbre and/or dynamics of audio signals. A mixer can mix analog or digital signals, depending on the type of mixer. The modified signals (voltages or digital samples) are summed to produce the combined output signals.

Mixing mixers are used in many applications, including recording studios, public address systems, sound reinforcement systems, broadcasting, television, and film post-production. An example of a simple application would be to enable the signals that originated from two separate microphones (each being used by vocalists singing a duet, perhaps) to be heard through one set of speakers simultaneously. When used for live performances, the signal produced by the mixer will usually be sent directly to an amplifier, unless that particular mixer is “powered” or it is being connected to powered speakers. Among the highest quality bootleg recordings of live performances are the so-called soundboard recordings that are sourced from this mixer output to the speakers.

Prior to the emergence of digital audio workstations (DAWs), the process of mixing used to be carried out on a mixing console. Currently, more and more engineers and independent artists are using a personal computer for the process. Mixing consoles still play a large part in the recording process. They are often used in conjunction with a DAW, although the DAW may only be used as a multitrack recorder and for editing or sequencing, with the actual mixing being performed on the mixer.

1.3                                          STATEMENT OF THE PROBLEM

In music industry, selection of different audio input to produce one output is always a problem in that it involves much labour. Mixers allow for precise tuning of mic inputs and speaker outputs. The result is clearer sound, and more volume from the sound system before feedback occurs.

1.4                                          RESEARCH OBJECTIVE /AIM

The objective of this work is to design an audio device which have and can accept four different audio inputs then with only one output. And the level of each audio input is controlled with potentiometer.

1.5                                          LIMITATION AND SCOPE OF PROJECT

This device was built using lm381 operational amplifier. Each of the amplifiers of lm381 is completely independent, with individual internal power supply decoupler-regulator, providing 120 dB supply rejection and 60 dB channel separation. Other outstanding features include high gain (112 dB), large output voltage swing (VCC b 2V) p-p, and wide power bandwidth (75 kHz, 20 Vp-p). High gain op amp combines up to four individually controlled input signals.