Questions tagged [audio]

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

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59 views

Noisy AES audio signal in studio installation

This is a question about digital audio cables. I know this isn't an audio engineering forum but the question's specific to the physical connections and there's limited info online which I can find ...
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0answers
58 views

Overtones(?) seem to be showing up in FFT of audio signal

I am processing audio data using a Teensy 3.2. I have a microphone attached to it, and am playing music in my room using some powerful speakers. When I look at data from the Fourier Transform of the ...
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2answers
72 views

Bucketing FFT into one-third octave bands

I'm trying to understand how to take the results of an FFT calculation and bin them to one-third octave bands. As my questions aren't about the code but about fundamentally understanding the arguments ...
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2answers
53 views

Remotely switch guitar (audio signal) with a relay. Which relay?

I want to build what is essentially a reverse AB signal box (a box to route one of two signals to a single output). These are reasonably common items, however I want to be able to switch this signal ...
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1answer
47 views

Interfacing the ESP32 A2DP Sink via I2S with the STM32

hope y'all are well and safe. I am back again! Woooo! Problem: The sound produced is really glitchy and the audio can be barley made. Setup: I have an ESP32 using the A2DP profile as a BT sink to ...
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1answer
91 views

LM393 comparator misbehaving and causing issues

I've been stuck on (what seems to be) a very unusual issue with a little audio circuit I’m designing. I wonder if anyone here can quickly highlight the flaws of my design and/or offer an insight into ...
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1answer
51 views

Problem in microphone circuit

I've placed the circuit on the breadboard and found an unexpected low-frequency noise appearing again and again. The computer microphone doesn't show this type of distortion. But my circuit is showing....
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2answers
53 views

i want to know if the potentiometer is broken or just dirty and if it's broken can i find the same in the market? [closed]

Hi i have speakers labtec arena 530 . i opened the main speaker and the problem is from the potentiometer I can make a brigde and connect 2 pot of the potentiometer sound become clean but i loose the ...
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2answers
105 views

What's the role of capacitors in this circuit?

This is a followup from a previous question: Analysing signal unbalancing stage which was quite broad as it encompassed couple of things, but answer there pointed me in the right directions so I'm ...
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1answer
37 views

Simple speaker crossover 1st order filter design

Opened up an old speaker and am trying to figure out what is going on with this capacitor. The gray cord leading to the larger 16cm speaker cone is an 8Ohm/6.3W capable load and then there is a 1uF ...
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1answer
47 views

Analysing signal unbalancing stage

I'm analysing a particular schematic, an audio compressor: https://www.soundskulptor.com/en/proddetail.php?prod=LA502 The schematic is here: https://www.soundskulptor.com/docs/la502-schematic-03.pdf ...
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1answer
77 views

Generate +/- voltage outputs using two boost converters?

I am working on a project to power some audio equipment that requires +/- 15V DC. Output current load is about 250mA, maximum. I am wondering if there’s any reason I couldn’t create this using two ...
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25 views

How can I get rid of the noise from this audio amplifier (using a Kemo M031N)?

I am trying to wire up an audio amplifier circuit using the Kemo M031N 3.5W amplifier: I have connected the wires from the amplifier to a terminal block. With a suitable 10V power supply and a 2W ...
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36 views

My Firebird electric guitar's bridge pickup is operating at a very low volume. What could be causing this and how can I fix it?

I have a Firebird electric guitar with two mini humbucker pickups. Both pickups have been good since I got it, but suddenly the bridge pickup stopped working. The neck pickup is fully operational, but ...
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2answers
236 views

Should stereo speaker cables be elevated to avoid static electricity

I am contemplating a new design for speaker cable stand-offs. I am unable to find support, only opinions, about static electricity produced by carpet affecting AC current between amplifiers and ...
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1answer
109 views

NUCLEO-G031K8 ADC conversion for audio recording — bit resolution and recording quality

I am planning to use NUCLEO-G031K8 board as an audio interface for my electric guitar to computer. So I designed a circuit to amplify small signal of guitar. When I check board's datasheet it is ...
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2answers
68 views

Class AB power amp output

I'm in the process of designing a headphone amp for my car (long story). It's been a long long time since I touched on electronics so I've been doing a lot of reading on the topic of amps etc. The ...
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1answer
42 views

Workflow to test the quality of XLR microphone cables, and have a quantitative measure of this quality

I have more than 10 XLR microphone cables from different manufacturers (some of them quite cheap, some of them more expensive), and as I often do recordings (with condenser microphones) of music / ...
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0answers
76 views

Audio jack acts like an antenna?

I am using a simple pre-amplifier circuit for an electret microphone. Here's the schematic and the AC transfer function: The output is connected to a 3.5mm audio jack through a couple of half a meter ...
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1answer
80 views

Why would I want a 3.5mm stereo audio socket ground designed so they connected to the casing?

It seems most audio sockets have the the ground pin connected the outside of the socket so that when it's fitted in a casing it will be contact with it. Why?
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2answers
62 views

Controlling PWM with an external oscillator and a JFET

I'd like to control the pulse with modulation of a VCO with an external oscillator (triangle wave). The PWM circuit is a comparator fed with the triangle wave output of the VCO. The VCO schematic is a ...
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2answers
60 views

Audio: what do I need to do to get SPDIF data to a speaker?

I'm working on a speaker project where I'd like to use a microcontroller's SPDIF output (aka IEC 60958) to drive audio data to a speaker. I've' been doing research on the topic, and I'm having trouble ...
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1answer
53 views

Why can you simply short a line-level output to ground? [duplicate]

I've read that one of the ways to sum two line-level outputs into mono is to simply ignore the right channel and connect the left channel to the mono input. In doing so, it has been said that you can (...
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2answers
62 views

Why is it safer to not short left and right audio jack outputs together?

I've read that the best way to "mix" two left and right line-level stereo jack outputs is to first connect each to a 1k resistor and then to your mono input. Why is this preferred over just ...
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3answers
85 views

Audio Amplifier using an Op-Amp

I am experimenting with Op-amp for making a audio amplifier. I am using this circuit. I want to know if the values of C424 and C118 are correctly chosen here or do they need to be change? I hear ...
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3answers
100 views

Audio amplifier components

I want to understand the purpose of capacitors and variable resistor in the following audio amplifier circuit. Here is its datasheet. C118 at amplifier output pin. C424 between amplifier input and ...
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1answer
32 views

Virtual ground supply for audio-applications

The most common solution to provide positive and negative voltage to supply an OP-amp would be to use a voltage divider and another OP-amp. In this way the voltage "on the top" of the ...
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1answer
25 views

How does a channel know to drive in I2S TDM mode?

I'm learning I2S right now and am curious how to work in an environment where 8 or so audio devices could be in the setup. I understand TDM mode would allow the Controller (Master in legacy terms) to ...
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0answers
24 views

Connecting MAX9814 to Speaker

I am trying to build a fetal heartbeat sound detection using Adafruit AGC Electret Microphone Amplifier - MAX9814. I attached the MAX9814 mic to the hole of wood fetal hearbeat stetescope (picture ...
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1answer
72 views

MC1314 voltage controlled attenuator circuit not working on breadboard - what did I do wrong?

I have an old quadraphonic system with a problem that I've traced to what I think is an MC1314. (That's not the question.) So I ordered a replacement, popped in and it didn't solve the problem. I ...
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1answer
42 views

Building a voltage adjuster circuit

I've been trying to build an op amp circuit that takes an analog signal from my electric guitar of around -1.5 to 1.5 V to a voltage level of 0 to 5 V, so that I can put it into the ADC of a ...
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2answers
47 views

Terminating an audio line-in signal when source is disconnected

I've been trying to DIY a home audio setup. We have a pair of speakers in the ceiling of an upper floor (previously installed), and a new TV on the same floor. We wanted the sound of the TV to come ...
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1answer
70 views

Using an LM358 as line level buffer

Recently, I've acquired an old SNES, specifically the SNSM-CPU-1CHIP-03 model, with no audio output. I traced the issue to a dead S-Mix chip, essentially a buffer between the audio DAC and the line ...
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2answers
62 views

Do class D headphone amplifier ICs typically contain integrated step-down converters?

Headphones can range in impedance from 8 ohms to a couple hundred ohms, and many only require a few milliwatts. This means that - for a low impedance headphone - only a few hundred mV RMS will be ...
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1answer
53 views

How should microphone impedance relate to input impedance?

I have: a Boya BY-MM1 microphone which has a nominal impedance of 300 ohms a Steinberg UR-12 with a balanced microphone input that has a nominal impedance of 4 kOhm I connect the microphone to the ...
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1answer
30 views

3.6 Vo-p rated buzzer on 5 V Arduino circuit

As a small buzzer to output simple audio, I am considering the Jiangsu Huaneng Elec MLT-5020. Other buzzers of that size are also an option, as long as their footprint isn’t much bigger than 5×5 mm. ...
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1answer
43 views

2 channel audio splitter passive

I have a Scarlett solo like the one above and I need a way to split the output of the Mix boards Auxiliary output into two level controlled signals. This Scarlett puts the Instrument on the left ...
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0answers
60 views

Why is the STM32 reference manual stating the wrong sample frequency for I2S?

This could be a misunderstanding but everything I have gathered and seen it looks like there's a disconnection on what the reference manual says. On Pg. 2212, in the STM32H753ZI it states: "The ...
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0answers
70 views

Audio mixer on battery power

I have an audio mixer which can run on two 9V batteries in series. I'd like to run it off a single 12V supply. Can I use two 12V-9V DC-DC converters both running off a 12V battery? Will the ...
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4answers
92 views

Audio output voltage range

I'm working on a synthesizer project and I'm confused on what the final audio output voltage should be. The idea is that I would send the audio to a speaker or headphone amplifier, so I don't have to ...
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1answer
43 views

Debugging Signal Distortion/Oscillation

Finally built up the circuit below that I've been designing/toying with in LTSpice and its working OK but I'm wondering if an experienced eye might be able to quickly label what/why the oddities are ...
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2answers
82 views

Click-and-pop suppression when circuit is not yet powered

Problem description: Power supply, for some reason, false-starts on power on of the device: the red is system +5 V supply rail, and yellow is my device's 3.3 V buck converter powered from the system'...
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1answer
147 views

How can a marginal connection become “good” by just applying a little more voltage?

"On the side" I do a fair amount of repair work to guitar gear -- Amplifiers, pedals, guitars, etc... I've had a similar symptom occur on different repairs, and found the same root cause for ...
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0answers
21 views

AV Receiver playing music using RCA Analog input (AUX) from Mobile 3.5 mm stereo source

I have a pioneer AV Receiver VSX-832-K with RCA AUX INPUT "input (Sensitive/Impendency ) 200mv/47K ohm" issue : when i am trying to play music from mobile using 3.5 mm headphone jack using ...
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1answer
99 views

Why does this cable have 3 wires to PCB on one side but only 2 wires on the other end? [closed]

I am working on a stereo receiver and was going to resolder some wiring. When I went to strip one wire on the 3-wire cable, the whole wire pulled out that was bare except for the half inch I was going ...
4
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1answer
85 views

The relationship between bit depth and SNR in ADC

An 8-bit audio signal has a theoretical maximum SNR of 48.16 dB (20log(2^8)). My question then would be, does this work in reverse, i.e. would an analogue audio (or video) signal with an SNR of <=...
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3answers
1k views

Do DSL / ADSL modems have an ADC with ~ 2 MHz sampling rate?

For fun and no real practical use, I'm trying to design a DIY modem that can transmit data over an audio line, like old 56k modems did. I'm studying how to pack bits of data efficiently in a 1k-15k ...
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1answer
35 views

Amplifier for Philips HTS7201/HTS7202

I have "inherited" a Philips 2.1 Home Sound System HTS7201/7202 The official user manual from philips can be found here: https://www.download.p4c.philips.com/files/h/hts7202_12/...
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1answer
56 views

How to calculate the input impedance and transfer function

I have the following circuit, that is used as a signal conditioning circuit in a audio system project. I am trying to calculate the transfer function and the Zin(input impedance) and Zout(output ...
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1answer
90 views

Guitar amplifier repair: burnt fuse, capacitor, what else?

A friend has asked me to take a look at his guitar amp: Peavey Valve King VK212. Problem: suddenly the amp stopped working during operation and the status lamp went off. First reaction: fuse ...

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