Questions tagged [audio]
Questions about designing electronics for measuring, processing, and amplifying audio signals.
3,164
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Eliminating Noise from Audio Amp Board Input
I made this project by shajeeb (linked below), and I am having trouble with noisy ground lines. The circuit I made is the same as the diagram below except for where I connect the speaker and amplifier ...
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Which capacitor for DC blocking in audio applications?
Which capacitor (electrolytic, film, ceramic) do you use for DC blocking in audio applications? From what I have seen most people use electrolytic capacitors.
But, also from power decoupling theory ...
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Why am I not getting an output from this breadboarded phaser?
After following along with a hobbyist's video, I breadboarded a phaser. Unfortunately it seems my circuit is not achieving anything close to what the hobbyist achieved with his.
I believe the issue is ...
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Connecting Headphone to Phone and Laptop via Switch
I am trying to build a small circuit which will connect my phone, laptop and headset with a switch.
So in state 1, the headphone and phone will be connected
and in state 2, the headphone and laptop ...
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How can I remove DC from an audio signal?
I am trying to "isolate" an audio signal that is transmitted on top of a 24V (DC) power supply voltage.
This construct is used in door intercom systems from TCS.
The audio signal is the ...
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Connecting an input and output to my Bluetooth headphones [closed]
I would like to connect my desk phone to my Bluetooth earbuds. I can unplug the cable from the handset of the desk phone and I can find a one way Bluetooth connector so I could listen to the output ...
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Capture audio from TCS Intercom BUS
I try to monitor and capture audio on a TCS Intercom.
There a several projects out there who have revers engineered the bus protocol.
I got it working to see activity on the bus when someone rings the ...
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Confused about how to wire headphone jack with a schematic
I've been trying to make an LED driver that responds to a signal sent over an audio cable and found this schematic:
I'm pretty sure that the middle ring on the jack and socket (third contact) is the ...
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Is there any problems with this baxandall tone control circuit ? Can you guys review it? [closed]
Can you guys review this circuit and tell me if there is something I am doing. As this is my first time?
I have a vague idea of impedance. Can you guys check that too. Share any good resources to ...
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How to DIY BaoFeng radio-to-soundcard cable?
I've got a cheopo BaoFeng UV-5RE that I'd like to try as packet radio.
I've snipped the plug off of the headset that came with the handheld, soldered it onto some breadboard cables, and did the same ...
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Noise issue when powering several audio devices from the same power source
I'm working on my portable music production setup and I'm having noise issues due to connecting all my gear to the same power source.
I have three devices (a sampler, a keyboard/synthesizer and a ...
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Accuracy when measuring THD with LT Spice for AB Audio Amp
I've designed and built my own AB class audio amplifier circuit. I designed it to have as low THD as possible, using LT Spice to run my simulations with the .four command, so I created a bunch of ...
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Arduino's impedance in breadboard circuit
(Warning, as this is a long question, asked by students that don't know what they're doing. Perhaps our questions are too general and can't be answered but at this point we'll take all the help we can ...
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Do we need to guard the input traces of an audio power amplifier?
This is a continuation of this question. I am using an LM4670SD/NOPB in my design. The IC has a 5 V supply.
The input of the power amplifier (+IN & -IN) comes from a smart module from Quectel.
...
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How to scale audio signal from PCM data to a dB SPL value?
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I've got a set with MEMS microphones that measure audio signals at ultrasonic frequencies. The MEMS microphones have a PDM output which is then converted into PCM (this is necessary to allow for a ...
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Amp troubles - noisy TEA2025
Recently I got my hands on a small amplifier board containing two TEA2025 ICs. Not sure what had it been used in previously, but the sound was acceptable, at least when removing some resistors that ...
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How to make an audio 5.1 switch?
I'd like to make a 5.1 audio switch to enable my 5.1 audio system (+mic+headphones) to be available for any of the 4 computers it can be connected to.
Something "like" this (using 5 "...
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Laser communication system to transmit Audio
The audio in these two circuits is only transmitted when they are both connected to the same battery (Vcc), and only the laser control audio level not the transmitting process.
When I connect the ...
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Identifying this coax connector?
Circular 1-pin coax connector. Trying to identify so I can buy a new socket for it.
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Unity Gain Buffer Output Impedance
First time here. I'm not an engineer so please pardon my lack of technical expertise. Thanks in advance for your help!
Here's is the circuit in question:
I've been told that R5 (10K) sets the ...
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Down-mixing 7.1 to 6.0 channels for digital pinball cabinet [closed]
I have a home built digital pinball cabinet with a 6.1 speaker setup and 6 channel input, the subwoofer is driven from the front speakers in a separate amplifier board.
The audio is driven from an ...
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Audio Power Amplifier Layout clarifications
I am using LM4670SD/NOPB in my design. The IC is working at 5 V supply.
This IC requires an 8 Ω speaker.
My first question is,
In that case do the lines Vo1 and Vo2 needs a differential impedance of ...
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Modded speakers emit high frequency noise, how to filter it out?
I came up with an idea to convert my PC speakers into Bluetooth speakers. It's not really a serious project, rather a proof of concept, but I want to get it to work as well as possible.
Here's my ...
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How does one convert DC to AC in context of playing audio?
I'm working on a little gadget. A simple two button mini game with a simple oled i2c display. I wanted to add sound and a bit of music. Nothing too fancy, mainly drums using white noise and two or ...
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Impedance matching: headphones out / hijacked op-amp pin -> guitar input
I have a Vox "amplug" pocket amp which has a female 1/4" mono input, it's supposed to be dangling directly from the guitar's output jack, and has 3.5mm TRS headphones out. I'd like to ...
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Amplifier chassis noise when not earth grounded
I build a kind of audio amplifier (it's actually a mixer). The problem is that the output gives a high frequency pitch noisy sound as soon as I touch the front panel which is part of the chassis. It ...
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Random noise in speaker with ESP32+DAC+Amplifier
We are facing the following issue with our application board based off ESP32 module.
We are using PCM5102 from TI as a DAC running over a I2S interface. The DAC is connected to the TPA3136 amplifier ...
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How to mute microphone in 2-way communication when the speaker is active?
I'm making my own two way intercom for my house. There will be a speaker and microphone above the front door of my house (as well as a camera). When someone rings my doorbell, I get a notification on ...
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Getting noise when connecting speaker out of SIM800l to Raspberry Pi
I was trying to make a roaming device which helps me route my calls through the internet, to save on my bills while on international roaming.
My setup is like this:
GSM module SIM800l, Raspberry Pi 4, ...
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Split and mix audio signals
I need to feed input to an audio amplifier from an USB DAC. The audio amplifier has separated inputs for headphone and speaker but DAC has only one output (stereo). Moreover the speaker input is mono ...
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Real-Time Audio Processing
this is my first post on here so I hope I am in the right directory to ask this or if there's another channel I should sent this in, let me know.
Basically, what I am trying to do is use a sound ...
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THAT4315 audio analyzer - capacitors getting hot
I have designed a audio spectrum analyzer circuit with THAT4315 and a drivers for IN-13 bar graph nixie tube to visualize the signal level.
To supply +-12V to the opamps, the Meanwell NSD15 module is ...
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Inrush current limiter thermistor acting up
One of the power amps I am working on uses a thermistor for inrush current limiting (SL15 25003) as shown in the schematic below (ICL1). When I was testing the unit it seemed to me that there was some ...
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Sharing ground between circuit and audio input?
I'm trying to build a VU meter circuit, and followed this guide/diagram (link)
I understand how the circuit should work in theory (mainly the OP-amps and the "logic"), except for the ground ...
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Name and cause for phenomenon in microphone preamp output as seen on scope screen
What might cause 1 kHz sinusoidal signal to change such as seen on the screen? How is this phenomenon possibly called?
I have quite a lot of hand microphones with built-in opamp preamp and electret ...
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Analog signal input from device with different ground reference
I am somewhat new to the world of electronics, but am now trying to design my first more complex PCB. I am trying to make a set of battery powered earphones that take an input from a 3.5mm audio jack ...
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Hum without ground loop
I have an audio measurement system. The system is connected to and powered by a laptop. The system has no other connection to the AC grid. Now, if the laptop is connected to the AC grid and i measure ...
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Latching Switch Reverse
I have a latching switch and I want to know if there is anyway I can change the switch, so that when it is pressed the circuit is open, but when it is released the circuit is closed.
The situation ...
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Line-out vs headphone-out impedance
I'm thinking about the example of two output jacks on the back of a computer, one for line out and one for headphones. I understand that the line out in generally an "unamplified" signal and ...
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Is it possible to add headphones to a Geiger counter circuit?
The main problem is as follows. From what it seems, most Geiger counter circuits opt for a piezo clicker. I'd like to just plug in a 3.5mm audio jack and be able to hear when pulses come in. The ...
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What might be killing the output to my amp, with every modification I try to make to my audio circuit?
I’ve been working on an audio project connected to a unique Stylophone-type keyboard (that I designed), using a 555 timer for the main circuit. I built a really cool box with 5 little powered outlets ...
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BA3121: Ground loop supression is great, however, very thin audio quality
Recently I bought a couple of BA3121s to fight the annoying ground loop problems when using several/separated modules (MCUs, Bluetooth, USB etc.) in class-d amplifier audio projects where all the ...
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Calculating audio sample output rate for synthesizer
I'm building a synthesizer on an FPGA and I'm having trouble calculating sampling rates. Currently, I'm running a system clock at 98.3 MHz and I want to produce 16-bit audio at the output.
I've got a ...
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Unstability with TDA2002 bridge configuration
I'm trying, for MONTHS (obviously not everyday, but I spent at least more than 80 hours on this) to do a 15 W audio amplifier with two TDA 2002's in a bridge configuration, following the circuit ...
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Can a ferrite choke/bead suppress unwanted audio signals (maybe mobile phone induced)?
I use a headset with a normal 3.5mm audio cable (not USB). Most times I have excellent audio quality, but in a large office building, I sometimes get very bad signals injected from an unknown source. ...
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STM32F446 and external oscillator
I am currently building an audio guitar pedal. I was suggested to use an external clock as reference for my CODEC and MCU.
I've been reading the "Oscillator design guide for STM8AF/AL/S, STM32 ...
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Maximum voltage/current on a passive 8 ohm buzzer
I have a buzzer with:
8 ohm
1 watt rated power
Resonant frequency: 700/600 Hz
In order to make it sound, should I apply a PWM with 700/600 Hz, and turning ON and OFF?
What is the maximum voltage? ...
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How do I remove electrical interference when using same source power?
I have a microphone receiver and a raspberry pi. I'm trying to power them using one DC jack. The receiver uses 12v and the PI uses 5v. The PI is outputting music which goes into an IN port on the ...
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PCM1789 DAC direct connection to TPA6138A2 headphone amplifier?
Is it possible to directly connect PCM1789 DAC to TPA6138A2 headphone amplifier?
According to datasheet PCM1789 output are differential outputs and the input of TPA6138A2 is also differential inputs. ...
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Record audio with digital I2S MEMS microphone and store audio as wav file on PC
I would like to use a digital I2S microphone to record audio and store it as wav on a PC, preferably over serial connection. I have tried this with the boards ESP32 dev kit v1, MKR Wifi 1010 and ...
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