Audio Electronics

An electronics course with a focus on audio equiptment analysis and circuit design. Coursework included basic electronic components and theories, passive filtering, transformers, operational amplifiers, equalizers, compressors, microphone preamps, and analog effects including reverb, flanging, and chorusing. All circuit designs were simulated using Circuit Maker.

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Projects

• Lab 1 - Voltage Divison and I/O Impedance

  Report

  An introduction to Circuit Maker. We simulated several basic circuits including a voltage divider and became familiar with performing DC and AC circuit analysis.

• Lab 2 - 1st Order Passive Filters

  Report

  In this lab we began working with passive filters. We created several low pass filters and analyzed their frequency response. We learned how to calculate a circuit's transfer function and use that to design other filters.

  

  

• Lab 3 - Shelving Filters and Loudspeaker Crossovers

  Report

  We improved on the simple high pass and low pass filter design to create more practical variable shelving filters. Then we applied those shelving filters to design loudspeaker crossovers that split frequencies into high, low, and middle bands to be played with separate drivers.

  

  

  

  

• Lab 4 - Transformers

  Report

  Experimenting with transformers. We created some circuits in Circuit Maker that utilize transformers including a balanaced/unbalanced signal conversion circuit and performed transient analysis to observe voltage changes and phase shifts.

  

  

• Lab 5 - Op-Amps

  Report

  Using operational amplifiers in our circuits to design a practical amplifier for a guitar that fits our required specifications of up to 40dB max gain and a sufficiently wide frequency bandwidth. We also used an op amp as a unity gain buffer to match impedances between the guitar and our amp.

  

  

• Lab 6 - Microphone Pre-Amp Design

  Report

  We designed microphone pre-amps; versions both with and without a coupled transformer. Our design specifications included designing for a max gain of 60dB and designing for the highest possible gain while maintaining the upper cutoff frequency of 20kHz. The calculations involved accounting for all parts of these multi-component circuits.

  

  

• Lab 7 - Filter and Parametric EQ Design

  Report

  A parametric equalizer is an equalizer that has multiple bands and lots of control over multiple parameters. They are designed to use variable filter types and allow control over the center frequency, amplitude, and Q factor. Our parametric EQ module was designed to control one band with the potential to be cascaded into a full multi-band unit.

  

  

  

  

• Final Project - Complete Mixer Design

  Report

  Our final project combined all of the components we learned throughout the semester. We created and simulated a full mixer console that controls signal flow from microphone input to a summed, balanced output. The stages of this console include a microphone preamp, a rumble filter, a parametric EQ, a 2-band shelving filter, a channel monitor with 2 aux sends, and the final mixer output unit that combines all input channels into a single balanced output.