Preliminary Design Report with Diagram: Hybrid Synthesis | EEL 4924, Papers of Electrical and Electronics Engineering

Download Preliminary Design Report with Diagram: Hybrid Synthesis | EEL 4924 and more Papers Electrical and Electronics Engineering in PDF only on Docsity! 1 EEL 4924 Electrical Engineering Design II (Senior Design) Preliminary Design Report with Diagram(s) 25 May 2009 Team Members: Name: Jamie Madaris Name: Jack Nanney Project Title: Hybrid Synth Team Name: Synthesize Me 2 Table of Contents Project Abstract ................................................................................................................................3 Features ............................................................................................................................................4 The Competition ..............................................................................................................................5 Technical Concepts...........................................................................................................................5 Cost Objectives/Components ...........................................................................................................9 Division of Labor .............................................................................................................................9 Timeline............................................................................................................................................10 References........................................................................................................................................11 5 The Competition: There are not many analog synthesizers in the market today The prices of these range from $300 to $3000 with the majority costing over $2000. Most allow for MIDI inputs. This synth will attempt to be a reasonably priced portable synth for the everyday musician. This will allow for it to be easy to use on stage at a concert. A comparable competitor is the Moog Minimoog Voyager (http://www.moogmusic.com/voyager/?section=product&product_id=161). The rackmountable version will be comparable. However this is a higher end product which has greater digital control which allows for presets. Other competitors have digital oscillators and analog filters and amplifiers. On such example is the PIC synth (http://www.synthdiy.com/show/?id=4142). This is a PIC micro processor as the oscillator. Technical Concepts: There are several different methods for audio synthesis. The most popular methods are additive synthesis, subtractive synthesis, and modeling synthesis. Additive synthesis creates its sounds by adding together weighted harmonics to produce a waveform. This is essentially the Fourier series. Subtractive synthesis involves beginning with a harmonically rich source and apply filters to remove and dampen the harmonics to create the sound desired. Modeling synthesis uses mathematical formulas to emulate sounds of instruments. This is usually implemented with DSP processors. Subtractive synthesis will be used for this project. This is used over other types of synthesis because it is more easily implemented using analog circuits. This is the type of synthesis used by a majority of analog synthesizers. The VCO will output a square wave, a triangle wave, and a ramp wave. A square wave contains odd numbered harmonics each dampened by the inverse of its order. The 6 Fourier representation of this is shown in Figure 3. The Triangle wave also contains the odd harmonics however the harmonics are dampened by the inverse of the square of the order. The Fourier series for this is shown in Figure 4. The ramp wave contains even and odd harmonics. The harmonics are dampened by the inverse of its order. The Fourier series of this is shown in Figure 5. Figure 3: Square wave Fourier Series (http://en.wikipedia.org/wiki/Square_wave) Figure 4: Triangle wave Fourier series (http://en.wikipedia.org/wiki/Triangle_wave) 7 Figure 5: Sawtooth wave Fourier Series (http://en.wikipedia.org/wiki/Sawtooth_wave) The oscillators are then filtered. This allows for the some of the harmonics to be removed and enhanced so that the desired sound can be found. The filter used will contain low pass, high pass and band pass outputs. The center frequency will be voltage controlled. This allows it be modulated by a LFO and by a attack, decay, sustain, release envelope generator. The filtered signal is then amplified for output. The amplifier is voltage controlled This allows for it to be modulated by a LFO and by a attack, attack, sustain, release envelope generator. The LFO modulation will create a change in the volume called a tremolo effect. The envelope will create the shape of the sound which will effect the allow the synth to emulate sounds as varied as a trumpet and a violin. The envelope generator is used with the VCF and the VCA. It controls how the signal enters the VCF or VCA. The generator has four main components, attack, decay, sustain, release (ADSR). This is shown in Figure 6 below. When used with the VCA it creates the timbre of the sound. Controlling these parameters can make the synth sound like any instrument from a horn, to a guitar, to a violin. Figure 6: ADSR Envelope from http://ems.music.uiuc.edu/beaucham/software/m4c/m4c_intro_html/M4C_intro.ADSR.png The analog modules will be controlled digitally. The controller will have a MIDI input. This 10 Demo (team) 12 1 0 0 References: 1. Jenkins, Mark. Analog Synthesizers Understanding, Performing, Buying- from the legacy of Moog to software synthesis. New York: Focal P, 2007. 2. Friedman, Dean. Synthesizer Basics. Amsco Publications, New York. 1986 3. "MIDI Message Table 1." MIDI Manufacturers Association. 20 May 2009 <http://www.midi.org/techspecs/midimessages.php>. 4. “Synthesizer” Wikipedia.com, 25 May 2009. <http://en.wikipedia.org/wiki/Synthesizer>. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Introduction (team) Research/project proposal (team) VCA, VCF, VCO, ADSR design (Jack) Analog Testing (Jack) Atmel Processor (Jamie) DA Converter (Jamie) Milling PC Boards Prototype (Team) Finished Product(Team) Demo (team) Available Weeks PlannedExtensionDown 11 5. Music From Outer Space. Ray Wilson. <http://musicfromouterspace.com/>