Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 28 | Saxophone Effects Pedal |
Eliseo Navarrete Peter Hevrdejs Sean McGee |
Prashant Shankar | appendix1.zip design_document3.pdf final_paper1.pdf photo1.jpg presentation1.pptx proposal1.pdf |
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| **Members:** Peter Hevrdejs [pdh2 – In Person], Eliseo Navarrete [eliseon2 – Online], Sean McGee [seantm2 – In Person] # **PROBLEM:** There are currently no quality effect pedals on the market specifically designed for horn players. The market is currently dominated in catering towards electric guitar / bass players - with the simplicity of using unbalanced inputs. There are pedals with balanced inputs made for vocals, but the problem is the circuits are designed for emphasizing typical vocal frequencies, not brass. Running a brass instrument through these often results in a "tinny" or some may say even comedic sound unfit for live performance. # **SOLUTION:** We propose building a multi effects pedal designed specifically for saxophone. Since the majority of microphones use a balanced output, we will need to implement circuit designs not only to that type of input, but also the frequency range of a saxophone. In our pedal, we will implement a preamp and equalizer that will solve the aforementioned “tinniness”. The user can elect whether or not to utilize practical performance effects - delay and reverb. The delay and reverb will be implemented on a digital signal processor while the preamp remains based in analog due to the time, cost and complexity to model distortion. The EQ will be implemented in either analog or on chip after comparing what works best for our application. All circuit components will be housed under an enclosure, durable enough for touring. # **SOLUTION COMPONENTS:** **ANALOG PREAMP [FIRST SUBSYSTEM]** The preamp section will have the audio from the microphone go into 2 or 3 gain stages (this will be decided based upon the specs of our design). The preamp will be transistor based for a transparent, clear sound. This decision will help achieve the desired tonal quality for sharp attack instruments. The circuit will also be transformer-coupled at either the input/output of the preamp (This attribute gives the signal more "color" or distortion to the tone but will take up more physical space). **EQUALIZER CIRCUIT [SECOND SUBSYSTEM]** The EQ section of the circuit will be dispersed across 5 potentiometers focusing on 5 different bands of frequency to allow for minute adjustments from the instrument preset. Since analog and digital EQs will affect the signal differently, we need to evaluate whether this system will be implemented on the DSP or as an analog circuit. **DIGITAL EFFECTS [THIRD SUBSYSTEM]** The digital processing section will utilize a processor designed for handling audio applications. After the EQ, the delay and reverb can be turned on and off through latching foot switches. The delay will feature 3 potentiometers that affect the blend (wet vs dry signal), time (how long the delay trails), rate (how fast the note repeats). The reverb will feature 2 potentiometers that affect blend, decay (how long the reverb lasts). **MULTI-INSTRUMENT ACCESSIBILITY [STRETCH GOAL]** We can expand the capability of this pedal by making EQ presets to the desired frequency ranges of several instruments. If we have the time to do this, this will feature an interface that could easily select different options, or even user presets. # **CRITERION FOR SUCCESS:** - Preamp functionality - amplifies instrument signal to audible amplitude - EQ correctly sculpts (filters) frequencies - DSP successfully converts audio signal from the first module into useable data for the second module - Delay effect repeats input signal at given time / periodicity - Reverb effect trails by specified time |
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