Electrical and Electronics Commons^™

4-Band Personal Eq Device, Carson Kellerman

Electrical Engineering

The device is a 4-band EQ with 3.5mm audio input and output jacks. The device has 4 adjustable EQ bands. Each of the 4 bands are adjustable via knob potentiometers, and are able to boost or cut their respective center frequencies of 150Hz, 400Hz, 2500Hz, and 10kHz from -15dB to +15dB. The device is battery powered off of 1 9V battery and is able to function for 10 hours before needing to replace the batteries. The device has a Total Harmonic Distortion of less than 1% and a Signal to Noise Ratio greater than 60dB. Overall, this device allows music …

Cubicom: Noisy Office Environment Communication Device, Nicholas Alan Maley, Joshua Michael Heeren, Alejandro Peña

Electrical Engineering

The CubiCom is a system that enables secure and clear communication between users in a noisy office space. It can function in any small cubicle within a 12 foot radius. The system consists of a series of wireless headsets for 6 users to transmit and receive audio, and a communication box that facilitates this process. These headsets are noise-dampening, preventing ambient sounds from interrupting conversation and making sure that all parties can hear each other clearly. Line-of-sight (L.O.S.) with each headset is required to have proper communication between users. This feature ensures no one outside of the room can eavesdrop, …

Multi-Effects Analog Guitar Pedal, Carson J. Bryan

Electrical Engineering

The Multi-FX Analog Guitar Pedal includes the analysis, design, performance, PCB layout, and packaging of an industry-standard effects pedal for an electric guitar. This project takes an analog input signal and utilizes analog circuitry to give the user the option to customize the way that their playing sounds. Effects include the options to add equalization filtering and distortion. The EQ filtering will allow the user to attenuate or gain certain frequencies divided into the 3 standard audio bands: bass (20-300 Hz), middle (300-4000 Hz), and treble (4-20 kHz). The soft-clipping distortion stage will allow the user to move around the …

Behind The Ear (Bte) Hearing Aid, Marco Gaitan, Jaclyn Kimoto, Lawrence Lai, Billy Pho

Electrical Engineering

The product is a Behind The Ear (BTE) hearing aid with the capability to improve the quality of life for people with mild to severe hearing loss and caters to a different consumer through bold exterior design to increase awareness of deafness and normalize hearing loss. In comparison to In The Ear (ITE) and In The Canal (ITC) hearing aids, the BTE hearing aid provides the best amplification while retaining an affordable price. Sound amplification depends on two or more directional microphones embedded in the product to give users the ability to discern the direction of incoming sound easily in …

Pseudo-Stereo Audio Processor, Zachariah David Bunce

Electrical Engineering

Due to both technical and resource limitations, non-professional audio production must often record with a single microphone, creating a mono audio signal. Even some originally multi-channel audio files often combine the separate channels into a single channel to save memory. However, this channel limitation makes any music held within the audio duller during listening. The Pseudo-Stereo Audio Processor remedies this situation, introducing a quadrature phase shift onto a given single-channel audio signal, producing multiple phase shifted output signals. These separate fixed-phase output signals are then recombined to produce a variable phase difference, emulated two-channel version of the input signal, allowing …

Dual Method Headphone Amplifier, Joseph S. Gross, Timothy P. Murphy

Electrical Engineering

Many high impedance headphones underperform their full potential when directly connected to the audio source. Amplifiers boost the audio signal and provide the headphones with sufficient power to ensure their maximum performance. The invention of transistors caused vacuum tube implementation to decline, leaving many audiophiles unsatisfied with the transistor’s sound signature. Vacuum tubes and transistors both amplify signals, however the distinct “tube sound” has vanished.

We have designed and created a product where the user selectively switches between solid-state transistor and tube amplification to compare the sound signatures of each amplification method. The ability to switch between the solid-state and …

Baserock Bluetooth: Bi-Directional Bluetooth And 3.5 Mm Headphone Jack Compatibility Device, Jonathan A. Falco

Electrical Engineering

This project was proposed by a startup company from downtown San Luis Obispo called BaseRock. BaseRock sells a backpack containing subwoofers to allow the user to feel low frequencies of music. It is intended for concerts or personal use, listening to songs on an MP3. The main way the BaseRock backpack communicates with MP3s is via the headphone jack. With the introduction of the Apple iPhone 7 in September of 2016, BaseRock realized it was at a disadvantage. Millions of iPhone 7 owners and potential customers around the globe would no longer possess a headphone jack. BaseRock needs a Bluetooth-to-headphone …

Wireless Audio Bridge, Daniel L. Hodges

Electrical Engineering

Bluetooth, a wireless technology standard used to exchange data using radio transmissions, has made a significant impact on the audio technology industry, specifically the way people listen to music. This technology enables a wireless listening experience, eliminating the need for wires or cables between audio devices as previously required. Audio can transmit from a cellphone or laptop (an output device) to a pair of headphones or speakers (an input device) without any physical connection. Compared to alternative wireless listening solutions (i.e. FM transmitter, radio broadcast), Bluetooth offers greater reliability, audio fidelity, portability, and ease of use. To obtain this functionality, …

Dual Channel Matrix Switch Audio Receiver, Austin Fox

Electrical Engineering

The Dual Channel Matrix Switch Audio Receiver controls 2 separate audio output channels. Each channel plays any of the system's 3 inputs. This controller enables a user to play two separate audio signals through two separate speaker channels. The system design allows audio input from 2 RCA sources or 1 RCA source and a phono source. The system outputs an audio signal for each output simultaneously at up to 36W on each channel for an 8Ω load. The device allows a user to control the audio input and the volume of each output channel. An Arduino Uno R3 microcontroller interfaced …

Analog Violin Audio Synthesizer, Brandon E. Davis

Electrical Engineering

Abstract In the past decade, music electronics have almost completely shifted from analog to digital technology. Digital keyboards and effects provide more sound capabilities than their analog predecessors, while also reducing size and cost. However, many musicians still prefer analog instruments due to the perception that they produce superior sound quality. Many musicians spend extra money and accommodate the extra space required for analog technologies instead of digital.

Furthermore, audio synthesizers are commonly controlled with the standard piano keyboard interface. Many musicians can perform sufficiently on a keyboard, but requiring a specific skill set limits the size of the market …

3-Input Pre-Amp, Daniel Pico, Carla Salome Ramirez

Electrical Engineering

There is no commercial available pre-amplifier that takes 3 individual input signals and synthesizes them for an acoustic guitar. The acoustic pre-amplifier takes three separate small signal inputs and combines or isolates to endure amplification depending with user setting. The user deciphers which signal or signal combination is desired. The device features coil pick-up, microphone pick-up, and piezo disc pick-up for variety of tone quality and control.

Multiplicative Feedback Audio Distortion Circuit, Colton Parsons

Electrical Engineering

This circuit aims to distort an audio signal input in a novel and aesthetically pleasing manner. When it comes to the timbre of a note, even harmonics generally sound better than odd harmonics. Most forms of audio signal distortion (usually for electric guitar) primarily add odd harmonics to a signal, as this is easily accomplished by clipping the waveform. This project instead utilizes a signal multiplier in a feedback loop, with one multiplier input coming from the circuit’s input, and the other from the multiplier’s own output. This process creates even harmonics. A delay line is placed in the loop, …

Psuedo-Randomly Controlled Analog Synthesizer, Jared Huntington

Electrical Engineering

The goal of this project was to design and build a portable box recreating classic sounds heard in science fiction films. These include sounds ranging from droning hums to bloops and bleeps. Currently no other device is made specifically for generating these sounds. The user controls and manipulates the sounds produced using a combination of switches and knobs to shape the sound generation. The sounds are generated using analog electronics. The project was successful in meeting the desired goal by designing and building a Randomizer, MIDI controller, VCO, LFO, VCA, Ring Modulator, and Fuzz Section. The resulting device is useful …