The Stack Overflow podcast is back! Listen to an interview with our new CEO.

Questions tagged [audio]

Questions about designing electronics for measuring, processing, and amplifying audio signals.

Filter by
Sorted by
Tagged with
263
votes
3answers
36k views

What is it that strips vocals from audio when a 1/8" audio jack is partially unplugged?

Every once in a while, my eighth-inch audio jack will slip loose and I'll seemingly lose only the voice part of a track -- leaving somewhat of a "karaoke" version. What I would guess about how audio ...
52
votes
3answers
67k views

How important is impedance matching in audio applications?

How much will reflected signals matter in audio applications (say between an amp and a speaker, or a pre-amp and an amp)? Mostly with regards to fidelity and not power transfer. What are the ...
46
votes
3answers
8k views

Loud pop noise while plugging to a headphones jack

I have a Panasonic RX-ES29 boombox with a type C plug (ungrounded). I sometimes hear a relatively loud snap/pop sound in the right speaker of my headphones while I completely plug them into the ...
42
votes
6answers
162k views

What is the voltage range of a standard headphone jack from a phone?

I want to connect the output from the audio jack of an iPhone to an Arduino. What voltage range can I expect to see on the audio lines from the iPhone? I assume that turning the volume up on the ...
37
votes
6answers
36k views

Can an audio circuit be powered by a switched-mode power supply?

Most audio circuits are powered with large, heavy transformers and a small ripple after smoothing. SMPS are smaller and more efficient. EMI can be shielded by a metal enclosure and the output filtered ...
28
votes
3answers
10k views

Are audio cassettes FM or AM?

I know that cassettes store an analog signal, but is the signal Amplitude-Modulated (AM) or Frequency Modulated (FM)?
28
votes
2answers
9k views

How do media buttons on a plain wired headset work?

I mean the simple analog headset pluggable into the jack of a phone. Not USB, not bluetooth, not fancy proprietary plugs with extra connectors - just a generic stereo+mic jack. The four "bands" on ...
25
votes
5answers
5k views

Normal capacitor vs. audio capacitor

I'm building a power supply for old Schoeps CMT30F microphones. Standard condenser mic are 48V-powered nowadays, but these are 60s/70s Schoeps mic from RadioFrance/ORTF, customized at that time to be -...
22
votes
1answer
2k views

Optical audio transmitter can't handle speech

This is a question relating to my project on an optical audio transmitter. I wired up a very simple device in which I use an audio signal transformer (EI14) to modulate the intensity of a laser beam (...
22
votes
5answers
10k views

What's the best cable to transfer audio signal?

Sorry if this is the wrong place but I'm interested in a scientific and electrical explanation and not some HiFi voodoo magic. I guess you all have seen the discussions about expensive audio cables ...
22
votes
6answers
7k views

What makes a “balanced” audio signal?

What is "balanced" audio exactly, and why is it useful? I've read that it means there are two voltages, with one being the inverse of the other. A balanced audio receiver looks at the difference ...
21
votes
5answers
7k views

What set the speed in a cassette tape recorder?

I was wondering what set the rotational speed in a cassette recorder? I assume that the speed must be constant, but that means that the tape data would have different effective densities depending on ...
20
votes
2answers
20k views

White hairs inside a headphones cable

I have a cheap set of Phillips SHE3000 earphones with a broken wire on the plug. Since I was repairing another set of headphones, with the same problem, I bought an extra plug, just to try repairing ...
18
votes
6answers
20k views

Paper in oil (PIO) capacitors: what is special?

Many audio circuits use PIO capacitors. What are the electrical Characteristics of PIO caps that make them special (i.e. justify the cost)? Which parts of an amplifier circuit benefit most from the ...
18
votes
4answers
19k views

How does an audio jack detect when a speaker is plugged in?

Some sound card audio jacks can now inform recent Windows OS's that an audio device is plugged in. Anyone know how it does this? I'm thinking it uses some kind of voltage comparator or resistance ...
18
votes
3answers
27k views

DC biasing audio signal

I have seen a few different ways of adding DC bias to an audio signal. I have simulated them and they all give me similar results, but I cant Figure out is why choose A over B or C. My audio source ...
18
votes
3answers
97k views

Using a microphone with an Arduino

EDIT: I have been investigating in this problem for quite some time. It turns out to be a way more difficult project than I thought and not something for beginners. This requires expensive hardware (...
17
votes
9answers
6k views

DSP recommendation for beginners [closed]

I am considering a project involving a fair share of digital signal processing. As far as I know, the best type of IC suited for this are the Digital Signal Processors. I have never worked with them ...
17
votes
4answers
12k views

How could you transfer data over an audio line?

I'd like to pass some data over an audio cable (i.e from audio card to my cellphone) with a short cable. I'm looking for some ideas for algorithms for achieving this. They of course should include ...
16
votes
4answers
4k views

Can a power MOSFET for switching application be used as a linear amplifier?

Power MOSFETs nowadays are ubiquitous and fairly cheap also at retail. In most datasheet I saw power MOSFETs are rated for switching, without mentioning any kind of linear applications. I'd like to ...
16
votes
2answers
2k views

Can anybody identify this component (SPRAGUE 663044-4) on this vintage electronic?

I am repairing a vintage Seeburg/Gulbransen 'Select-a-Rhythm' drum machine from 1967, the kind you would sit on top of your organ and play along with. I am trying to distinguish what this component ...
16
votes
5answers
60k views

Simple Audio amplifier Using Transistors

I would like to build a simple audio amplifier using transistors. I know there are IC designs specifically for the task. But i want to use transistors so i can learn how to use them for amplification. ...
15
votes
6answers
5k views

Why do (microphone) preamp designs tend to limit opamp gain to max 60 dB?

Looking at many pro recording quality microphone preamps, I noticed that every design I looked at that uses an opamp (discrete or IC) limits the gain provided by the opamp to about max 60dB. While ...
15
votes
5answers
48k views

How does the phone detect if 3.5 mm jack circuit is closed?

I have an android phone to which i have plugged an earphones. So at the top of the phone, I get the headphone symbol which indicates that the earphone is connected (In other words, the circuit at the ...
15
votes
2answers
18k views

Single supply op-amp audio amplifier

I am trying to create an op-amp amplifier that would work from single 5V supply, and would be able to amplify -100mV to +100mV audio signal to around a 1V peak-peak or so. I've came across this ...
14
votes
5answers
25k views

Why are high end audio connections gold?

Silver has a lower resistivity than gold and is cheaper, so why are high end audio components gold plated?
14
votes
6answers
780 views

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 ...
14
votes
5answers
55k views

Over what frequency range can the microphone of smartphone receive the sound?

I have a project in which I am considering using the microphone from a smartphone for the reception of inaudible signals (> 15khz). What is the frequency range that such a microphone of receive sound?...
14
votes
4answers
14k views

What is the advantage of optical TOSLINK over RCA coaxial cable?

A popular standard for the transmission of digital audio between audio devices has been the AES3 standard (also known as S/PDIF). The standard sends stereo PCM audio and of often found in consumer ...
14
votes
12answers
11k views

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 ...
14
votes
5answers
2k views

How to create large inductors (1H) for audio use?

I am building a tube amplifier, and have decided to add a 5ch EQ to it. Historically, the ones used in guitar amplifiers were all passive RLC filter style systems, with large inductances of 0.5 - 2H ...
14
votes
2answers
11k views

Understanding Audio Jack Connection

I have circuit that has an audio connector that has the following diagram. Audio connector is one that I am not familiar with. What I gather is that the rectangle on the left is the sleeve (entry ...
14
votes
2answers
38k views

What wattage should a headphone amp be?

I was at a local surplus store today and I got two LM386N ICs. I thought I could make a really simple headphone amp out of these. But I have no idea what the wattage of a normal headphone amp is. ...
13
votes
5answers
2k views

Where do overtones in a 555 generated square wave come from?

I have built a 555 oscillator and connected it to a speaker. Using an oscilloscope I adjusted the 555 to generate a 2.5kHz square wave. I then held a microphone up to the speaker and fed the input ...
13
votes
3answers
4k views

Accidentally downmixed stereo to mono, why does this work?

I have a cheap Chinese Bluetooth audio amplifier like this: It has four screw terminals for the speaker connections, namely L+, L-, R+ and R-. I accidentally connected a single speaker to L+ and R-, ...
13
votes
2answers
7k views

Want a USB mini-microphone array. Is it possible?

I have been learning a lot about adaptive beam-forming, and have been mucking around with various sims in MATLAB, etc. But what better way to understand something - truly understand it - than to ...
12
votes
2answers
21k views

Naively mixing two (or perhaps more) audio signals

this is my first question and I am very much a beginner in electronics so I apologize if this is a too stupid question. I have Atari punk console and another small homemade audiomaking circuit. These ...
12
votes
2answers
12k views

Audio using PWM, what is the principle behind it?

I have seen a schematic of a PIC board which uses filtered PWM to provide audio output signal to an audio jack. It shows PWM output filtered using 3 stages of passive RC filter followed by an LM386 ...
12
votes
2answers
12k views

Audio delay using discrete components

I would like to make a circuit that causes an audio delay using discrete components. I know I can do small phase shifts using an opamp, but I am looking for something in the millisecond or second ...
12
votes
3answers
2k views

Audio Amplifier Op amp

I'm trying to design a circuit in which a microcontroller produces a signal and then using an amplifier drives an 8ohm speaker. I've so far used LM386, but it cannot go above 1W, which turned out to ...
12
votes
2answers
6k views

Twin-T Active Notch Filter Analysis

Could anyone give me a hint in analyzing the Twin-T Active Notch Filter? I tried a delta-star transform, followed by nodal analysis, but ended up with conflicting equations. For an example, look at ...
12
votes
2answers
485 views

Straight from the datasheet: Is this really a sensible filter circuit?

Cirrus Logic CS42426-CQZ is an audio CODEC that I want to use in a custom USB sound card. You can download the datasheet from there. On page 61, the datasheet has a recommended circuit for each A/D ...
12
votes
1answer
841 views

Will this passive non inverting anti-log circuit work?

The potentiometer on the left of the circuit below is actually the output of a digital potentiometer designed for audio volume control, so its outputs are internally configured to offer 64 logarithmic ...
11
votes
2answers
6k views

What is this 3.5mm plug designed for?

Here is a technical drawing for a 3.5mm stereo audio plug, taken from a product datasheet (http://www.tensility.com/pdffiles/50-00396.pdf): The right-hand end is a standard 3.5mm audio plug. The left-...
11
votes
8answers
14k views

Maximum sample rate of Arduino Duemilanove?

G'day all! I have an Arduino Duemilanove hanging around spare at the moment and thought I might try a few audio interfacing projects. I'm just wondering what sort of sampling frequency I can achieve ...
11
votes
5answers
2k views

2-layer PCB design, through hole technology and ground plane

I am designing the layout of a PCB for audio applications (no digital electronics, only analog). All components are through hole, the PCB is pretty large (about 16cm x 10cm) and has 2 layers. Plated ...
11
votes
4answers
66k views

Best transistor to use for audio amplifier

This term, we will be designing an audio amplifier. So far in our lecture, we are still at BJT and based from what I've heard, FETs will just be partly discussed unlike the thorough one on BJT. Anyway,...
11
votes
3answers
7k views

Audio Amplifier PCB Design Tips

I am going to design a stereo audio amplifier with TDA2030A. This is going to be an amplifier that is going to be powered from 27.6V DC and 12W per channel. Is there any sources that I can learn PCB ...
11
votes
5answers
2k views

Building a synthesizer with no prior experience

I've got an extensive music background and have been infatuated with synthesizers since I was young. I had dreamed of going into an EE program to make my dream a reality, but I couldn't afford school (...
11
votes
3answers
5k views

What are some typical low cost microcontrollers and chips that are used in electronic toys?

I'm researching microcontrollers, memory chips, and sound chips for simple electronic toys. These toys might take user input via buttons or switches, and then play back sounds stored on a memory chip ...