Questions tagged [audio]

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

Filter by
Sorted by
Tagged with
6 votes
1 answer
839 views

My BJT audio amplifier circuit isn't working as expected

I am trying to design an audio amplifier circuit using BJTs. These are the requirements of the circuit: Input signal: 50-100 mV (It's the output of my iphone's microphone.) 2 W - 4 ohms speaker There ...
user avatar
22 votes
3 answers
32k 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 can't figure out why choose A over B or C. My audio source will ...
user avatar
  • 2,490
271 votes
3 answers
38k 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 ...
user avatar
  • 2,451
21 votes
2 answers
25k 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 ...
user avatar
  • 1,897
59 votes
6 answers
233k 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 ...
user avatar
19 votes
6 answers
63k 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 ...
user avatar
  • 337
58 votes
3 answers
76k 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 ...
user avatar
  • 944
26 votes
6 answers
8k 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 ...
user avatar
  • 55.3k
6 votes
2 answers
862 views

How to connect one Android mobile audio output to the microphone of another Android mobile?

This question is to help the "hard of hearing community" so that they can READ the phone/mobile call because they can not hear it. Android has some really good (and free, too) apps which can ...
user avatar
18 votes
3 answers
104k 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 (...
user avatar
  • 363
5 votes
3 answers
11k views

Ground loop? Switch mode power supply noise

I have a single 12V supply powering a 12V class D audio amplifier (Tripath TA2020 based, model 'SMSL SA-36') (C) and a very cheap 12V to 5V 2A rated switch mode converter (A). The 5V is used to power ...
user avatar
  • 333
3 votes
2 answers
2k views

Can I use a UA741 here?

I need to pass a domestic -10dbV audio signal (it should oscillates between -447mV and +447mV) to a microcontroller's ADC which only accepts signals that oscillates between 0V and 5V. I think that the ...
user avatar
2 votes
3 answers
4k views

Playing sounds on an AVR MCU [closed]

I never had to deal with sound and I am pretty sure some of you guys have some experience in that kind of application. My question is more about getting some tips on the different ways to implement ...
user avatar
  • 155
17 votes
5 answers
62k 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. ...
user avatar
  • 245
18 votes
4 answers
13k 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 ...
user avatar
  • 399
14 votes
2 answers
31k 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 ...
user avatar
  • 381
8 votes
2 answers
42k views

Connect speaker output to microphone input

What exactly is the difference between a microphone signal and a speaker signal? I want to make a simple cable to connect a PC speaker output to a microphone input. Does anyone have a good idea or ...
user avatar
  • 193
7 votes
3 answers
25k views

How to make my own volume control for headphones?

I have headphones that don't have volume control built in on the cable, so I thought why wouldn't I try to make one? However, I don't know where to start. Is it enough to just use a logarithmic ...
user avatar
  • 882
23 votes
5 answers
12k 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 ...
user avatar
  • 343
4 votes
2 answers
13k views

line-level audio into an iPhone headset jack?

What level and/or impedance matching (or pre-amp) circuits should be used to send a line-level audio signal into the mic input ring of an iPhone headset jack with minimal distortion and/or loss?
user avatar
  • 4,451
9 votes
4 answers
14k views

Can I use a PNP Transistor with an Electret Microphone to get an non-inverting output for my Arduino?

I'm looking to simply read the generic sound level from an Electret Microphone. I've seen a number of schematics with NPN transistors, that will provide an inverted output (~5V when quiet, ~0V when ...
user avatar
  • 1,141
5 votes
3 answers
10k views

How to read an audio signal using ATMega328?

I was trying to use the ATMega328 ADC port A0 to read a signal. The hardware I used was: Seeeduino Stalker Electronic Brick Shield Microphone Electronic Brick (I found a link to the original ...
user avatar
  • 1,933
5 votes
3 answers
2k views

What component to use for audio signal switching?

I'm looking to build a guitar pedal switcher based on a Raspberry Pi or Arduino (have not yet decided, but I have an unused Raspberry around and I lean towards that). Anyway, digital logic. Now, I ...
user avatar
  • 355
5 votes
2 answers
25k views

What is the typical max voltage for sound card line in? [closed]

What is the typical max voltage rms, peak and peak to peak for a sound card line in?
user avatar
  • 109
2 votes
3 answers
621 views

Single supply op amp to convert 0-5VDC to +/-2VDC (microcontroller to line level)

I am generating a 0-5 volt sine wave using an arduino with a DAC. I would like to level shift this signal (DC bias?) by -2.5 volts and have a gain of .8, so that I end up with a line level sine wave. ...
user avatar
  • 137
1 vote
2 answers
2k views

Making a Simple Audio Mixer

I'd like to make a simple audio mixer that takes in line level signals from various mp3 players, computers, etc. I found a simple schematic online, but I'm wondering if this will be okay for my ...
user avatar
  • 1,588
42 votes
6 answers
44k 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 ...
user avatar
  • 1,295
49 votes
4 answers
12k 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 ...
user avatar
  • 553
17 votes
9 answers
7k 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 ...
user avatar
  • 404
10 votes
7 answers
26k views

LM386 audio amplifier not amplifying

This is my first attempt at making a really simple audio amplifier. The schematics are below:- First I tried connecting the circuit to a 9V battery. (Multimeter reads around 8.3 Volts, which is in ...
user avatar
  • 237
10 votes
3 answers
12k views

Benefits of multiple op-amp gain stages in series?

I'm a bit lost in regards to how multiple op-amps in series will perform. My use case would be the amplification of low-voltage audio signals (4-50mVRMS) to roughly 8VRMS. I only found documentation ...
user avatar
7 votes
6 answers
27k views

MOSFETs or BJTs for using as switch for audio signals

I was wondering which component is better for using as voltage controlled switch for audio signals (e.g. music signal from mp3 player). Should I use MOSFETs or BJTs? The max rail voltage is ...
user avatar
  • 623
8 votes
1 answer
18k views

Using diodes to mix 2 audio signals into one set of speakers

I have the audio output of 2 computers connected to only one set of speakers. Each computer uses one of these external USB sound cards: And I use this splitter cable to wire the signals together: ...
user avatar
  • 429
19 votes
2 answers
51k 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. ...
user avatar
  • 5,103
11 votes
3 answers
17k views

How does this LM386 circuit boost bass?

I'm just starting out in Electrical Engineering and was wondering if anyone could clarify a question about the following RC circuit regarding the LM386. My question is about the following circuit: ...
user avatar
  • 137
4 votes
3 answers
3k views

My Atmega328 seems to be overkill, what should I use instead?

I'm using an Atmega328 chip with the arduino bootloader in a very small circuit. The sketch simply plays a tune using the tone() function to play a melody through a piezo speaker on a single pin. ...
user avatar
14 votes
2 answers
15k 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 ...
user avatar
  • 17.3k
2 votes
3 answers
3k views

Using a 1.5V battery to increase the voltage from a headphone jack so it can switch a transistor at lower volumes

I recently built a circuit using a 2N3904 BJT transistor with the hopes that when connected to a headphone jack, it would light a LED whenever an audio signal was passed through. However, I found ...
user avatar
  • 192
13 votes
3 answers
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-, ...
user avatar
  • 463
11 votes
8 answers
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 ...
user avatar
10 votes
3 answers
4k views

How can I effectively reduce the voltage needed to activate a transistor?

I have built a circuit which basically connects the line out (audio output) of a music playing device to a set of LEDs (actually a huge strip of around 200 LEDs), so they flash in time with the music (...
user avatar
8 votes
3 answers
9k views

How do I amplify a dc voltage that is too weak to trigger the base in a transistor?

I'm trying to take the voltage output from a 3.5mm audio jack and have it light up an LED according to it's voltage. I was going to attach the left audio cable to the base of a 2222n transistor which ...
user avatar
7 votes
4 answers
3k views

Isolating audio ground between devices

I'm planning a build for a guitar amplifier with 2 stages, the first being a tube pre-amp and the second stage being a solid state amplifier. Both amplifiers will be powered from the same source, a ...
user avatar
6 votes
2 answers
18k views

Driving LEDs from audio signal

I am making this very simple hobby circuit and I need help. This utilizes the sound (variations) from the device through the jack to provide light (intensity) variations in the LEDs using TIP31. ...
user avatar
  • 71
5 votes
2 answers
5k views

How to store audio data for AVR project?

I see a lot of projects for AVR-based audio players that use an SD card to store the audio data. In fact, I am currently doing the very same thing on an Arduino and its Wave Shield, which has an SD ...
user avatar
  • 27.1k
9 votes
3 answers
3k views

Function of Specific Capacitor in Audio Amplifier's Negative Feedback

The audio amplifier that I am referring to here consists of three stages. Among others, the amplifier also includes negative feedback (NFB) that is made of two passive resistors. From the base of TR3 ...
user avatar
  • 2,280
7 votes
3 answers
62k views

How to determine appropriate speaker cable gauge?

When wiring speakers to a 100W consumer-grade amplifier, how do I select an appropriate gauge cable (for 8-ohm speakers)? Also, if 14 gauge cable is sufficient, what harm is there in using a heavier ...
user avatar
  • 27.1k
4 votes
1 answer
3k views

Convert Digital and Analog values to dB SPL

I am trying to create a sound level meter. I want to use an analog MEMS microphone (INMP510) and a digital microphone with I2S output (SPH0645LM4H). The sensitivity of the INMP510 is -38 dBV and for ...
user avatar
4 votes
3 answers
18k views

Cost Effective Solution to using PAM8403 as a headphone amp

I've just bought a PAM8403 pre-built circuit board for $1 on eBay, I was going to use it to drive a set of headphones but I neglected to consider that this is a Class D amplifier and will not take ...
user avatar
  • 143
3 votes
4 answers
1k views

Class A Amplifier Design: Emitter Resistance Voltage Drop

I am trying to understand the design principles of Class A amplifiers, primarily for audio purposes. I have read several times that "the voltage drop across the emitter resistor should be in the ...
user avatar

1
2 3 4 5 6