Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [music]

99 questions
53
votes
5 answers

Why does music synthesizer built from chain of astable multivibrator circuits get "out-of-tune" after a few hours?

I built a prototype keyboard/sound synthesizer using a chain of 13 astable multivibrator circuits whose outputs are connected to an audio amplifier chip (LM386) and speaker, all powered off a 9V DC battery. Each individual circuit gets tuned to one…
Assad Ebrahim
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32
votes
5 answers

Does cassette tape change its velocity while playing?

Looking at the old cassette tape, From the POV of the head, let's say that it reads at speed \$v\$ (the magnetic medium scrolls at speed \$v\$). But looking at the right wheel, which is the one that's pooling the magnetic medium - its radius is…
Royi Namir
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15
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12 answers

Polyphonic sounds from a microcontroller?

I can make monophonic sounds by toggling a single pin (at a varying rate) connected to a piezo buzzer. How can I generate two mixed audio signals in software to create polyphony? Here's the code I'm using to play a simple tune. #define F_CPU…
Toby Jaffey
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14
votes
6 answers

Legality of Reverse Engineering

If there was a "law/legal" stack exchange site I'd post it there, but it's in its infant stages in Area 51. I'm a musician and an electrical engineering student. I've designed a modification to the pickup system of my acoustic/electric guitar that I…
Andrew
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11
votes
3 answers

How are electronic musical greeting cards made?

I remember that long time ago, when I was a kid (in the 80s) there was some electronic greeting cards that when open up, start playing simple tunes through a small piezo-electric speaker. A quick look at the board reveal a small black chip and some…
tigrou
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8
votes
4 answers

Pressure/Force sensor

One of my students are planning to make a simple musical keyboard with PIC microcontrolers, using MIDI output. The main problem now is about the pressure/force sensor. I've found a good alternative in this question about flexiforce. I'm wondering if…
RMAAlmeida
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8
votes
6 answers

VCO for synth V/Octave and battery supply?

It's been a dream of mine to build an analogue synthesizer for a few years. In this time I've built VCOs based on the 555 timer, which I know do not generally have an accurate frequency response without a lot of additional circuitry. 555 VCO I've…
blarg
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8
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3 answers

How do I measure loudness?

I was toying around with an idea for a digital musical instrument with breath control. I've successfully experimented with pressure sensors and they are probably the right way to go, but my first idea was just using a plastic sealed microphone. I…
cmpalmer
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7
votes
3 answers

Random high-amplitude frequency in guitar effect circuit

I'm building an analog distortion effect for my guitar. During testing I measured a random 470 kHz signal with an amplitude of 500 mV. Where does this signal come from, and how do I get rid of it? I designed a op-amp circuit/PCB with a USB-C port…
Lukas
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6
votes
1 answer

Music through RF

I have recently been fascinated with wireless-ness. I thought of a little project so I could do a little research in this area. This project uses a circuit board found in a Christmas card or birthday card that makes it play music when the card is…
slashoofpez
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6
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1 answer

Can anyone figure out this (David Tudor) circuit?

Here's a link to the (crummy) schematic: It's a filter/phase shift designed by the experimental electronic musician David Tudor, for use in destabilizing audio feedback loops. The circuit seems unclear to me, and I don't understand the signal…
Greg
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6
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5 answers

How do I mix two audio tones from two 555s to make a polyphonic chord?

I have set up two 555 chips in astable mode to produce a tone each through a speaker. However, I am not sure how to mix them together to produce a musical chord. If I directly combine the two outputs from the 555s into a single output, it creates a…
thatsagoal
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5
votes
1 answer

Can I use an SMPS to power a audio TDA7293 power amplifier?

I have been gifted a couple of these TDA7293 Power Amplifier boards, and I need to give power to them. Description says *DC power supply: positive and negative 25-45V *The power of the transformer: 100w-200w The DIY Audio forums talk about using a…
ExcitingProjects
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5
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7 answers

Design for an analogue oscillator that doesn't drift in frequency?

VCOs (Voltage Controlled Oscillators) in analogue music synthesizers are notorious for drifting with temperature. What design solutions are there for an analogue audio VCO that keeps close (as in human hearing) to the frequency to which it's been…
Rob Kam
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4
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2 answers

DIY guitar effect - delay

I'm trying to build a guitar delay effect based on this schematic: (https://i2.wp.com/cdn.makezine.com/uploads/2009/09/echobenderrev02.jpg) I designed and oredered a pcb :…
Brunon
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