Questions tagged [audio]

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

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2answers
57 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
30 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
23 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
21 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
68 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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0answers
86 views

How can I protect myself against accoustic shocks [closed]

I am a conference interpreter and I use online platforms like zoom, webex... quite a lot for remote simultaneous interpreting as face to face meetings are getting rarer these days. I am concerned ...
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1answer
39 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
46 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
61 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
61 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
52 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
22 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
34 views

Turn on Raspberry Pi with amplifier

I'm using a Raspberry Pi as Bluetooth interface for my old Hi-Fi amplifier. I want the Pi to boot when I turn on the amplifier using it's main switch on the front. I thought of using a master-slave ...
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0answers
53 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
54 views

How to Apply RC Low pass filter at output of amplifier?

I'm trying to filter low pass, band pass and low pass, at the out of the amplifier of 32 watt TDA2050 for use diferent speakers with diferent ranges, but it seems not work, for example the voltage ...
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0answers
69 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
91 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
76 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
139 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
96 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 ...
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1answer
83 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
30 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
52 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
89 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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5answers
108 views

Why is output power such a meaningful quantity in speakers?

Loudspeakers, for example, should be impedance matched to deliver the highest power from the source to the speakers. But why do we care about power so much? A speaker is at its simplest, a coil around ...
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1answer
102 views

Looking for audio amplifier circuit using 2SC1050 transistor

Will I be able to find any audio amplifier diagrams using 2SC1050 transistor? I've looked and looked, but can't find any. I mainly want to see what audio power out etc. so I can get an understanding ...
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1answer
42 views

How Can I Fix a Fraying Earbud Cable? [closed]

My KZ earbud is broken, I don't hear anything from the left speaker. After a quick inspection I noticed the cable is fraying. The cable is detachable but I don't want to buy a new one. Do you think I ...
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0answers
46 views

Adding a CV in to a simple oscillator

I am using an XR2206 IC to make a simple oscillator module. The documentation shows that it has a VCO as a part of the IC, and uses a variable resistor loop and a capacitor loop to control frequency. ...
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1answer
44 views

How can I make a L+R+mic audio dongle to record an Android phone's own output?

I'm looking for a way to wire the stereo output of a device into its own mono microphone input. This will be soldered as a 4 pin 3.5mm TRRS audio jack. I need to record the output of my smartphone on ...
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1answer
103 views

How can I convert an audio PDM bitstream into analog form?

I have collected PDM bitstreams from MEMS microphones and I'm looking to convert them into analogue form. Does anyone know some practical implementation details on how to do this (beyond a quote from ...
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1answer
53 views

Get clean line-level audio signal from a sound generator chip that is designed to drive a transistor as amplifier

(I removed both of the two old questions since they are going wild and off-topic, but the main concept is the same, just as title states. Also some details are clarified and informations are appended.)...
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2answers
65 views

Audio Demos on DE10 Standard not Working

I bought the Terasic DE10 Standard and am having issues trying to run the demos related to audio. I am trying to run the two demos, DE10_Standard_Audio, and DE10_Standard_i2sound, while connecting ...
2
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6answers
117 views

10Ω series resistor in output of headphones amplifier

I managed to reverse engineer a headphone amplifier in a USB DAC that I bought on aliexpress. As I expected there is a electrolytic capacitor in series to the output, but there is also a 10Ω resistor ...
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1answer
71 views

Hardware that can generate chirp audio signal

Basically I would like to generate chirp audio signal that sweeps from 16 kHz to 18 kHz, the signal lasts about 100 ms, no restrict requirements on the sound volume. I am able to generate such chirp ...
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1answer
102 views

How will wire wound resistors affect the synth's sound?

I am soldering up Music from Outer Space: Noise Toaster synthesizer. The guy who designed it said that carbon resistors should be used ("The resistors should be carbon composition or carbon film&...
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1answer
33 views

Is it relatively simple to design an ADC to ADAT interface with only a Toslink port?

For this project (I'm an experienced audio engineer but a relative beginner in electrical engineering) I really want to integrate a simple ADC to ADAT circuit in a patchbay I'm building so that I have ...
2
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3answers
127 views

Troubles on powering two (audio) circuits with single voltage source

I have a simple audio circuit that needs to be amplified. The circuit is a CMOS based circuit, running on 9V coming from a 12V battery pack stabilized with a 7809 IC. I have also an amplifier circuit ...
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1answer
30 views

Right approach to boost the current of a signal to drive a speaker

I have a circuit which can produce three different waveform signals ( Square, Sine and Triangle). The output amplitude of these signals goes from +5V to -5V Peak to peak. However the output from this ...
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1answer
71 views

Can a voltage divider be used for (input) jack detection?

I would like to detect when a jack is plugged into my connector. The circuit looks like this: One end of the jack is connected to a speaker, and the other to an audio source, such as a phone or mp3 ...
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2answers
113 views

Infant cry detector

I want to use an electret microphone to detect infant cry. I came up with this design: According to those papers: Pitch Analysis of Infant Crying Frequential Characterization of Healthy and ...
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2answers
72 views

Op-amp unity gain buffer introduces distortion in the LM386 circuit with high gain factor

I'm building a simple mixing stage, lowpass filter, and final amp in sigle supply (9v battery). I started from the LM386 circuit on the data sheet. It had a lot of distortion which was solved with the ...
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1answer
43 views

Connecting cell phone and computer audio through TRS and TRRS 3.5 mm audio jacks

I am trying to connect the computer audio output to the cell phone audio input and vice versa. There are two connection designs because I need to be able to connect both to a desktop and a laptop ...
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1answer
43 views

Debugging a SA 90.4 800W class-D audio amplifier

I am using a Re-audio SA 90.4 800W 4-channel class D audio amplifier (https://www.amazon.com/REAudio-SA90-4-4-Channel-Digital-Amplifier/dp/B00RE9EO7K) for some underwater piezoacoustics experiment. ...
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2answers
78 views

High-Z input in audio interface

In audio interfaces (e.g. USB) you often find one input that can handle XLR and jack. The jack input is usually used for an electric guitar input. For that, there is a "High-Z" switch to it. ...
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0answers
52 views

Need help with simulating a 3-channel LED color organ in MULTISIM

I have been trying to simulate a LED colour organ in MULTISIM (literally) for hours. I don't understand why is it not working. My end goal is to get to simulate this on MULTISIM. Here's the circuit I'...
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2answers
34 views

FFT Frequency Bin - Impact on Energy Totals

If I reduce the number of samples used for an FFT (increasing the width of the frequency bins), is it correct to say that the energy in two bins with smaller frequency bins (eg. 10kHz-20kHz and 20kHz-...

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