Questions tagged [audio]

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

313 questions with no upvoted or accepted answers
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2answers
332 views

Enhancing the bass response of an audio isolation transformer

Below is a simple buffer circuit using an isolation transformer : The green trace is the output of the transformer and the blue trace is the input signal (20hz to 20Khz sine wave). As you can see the ...
3
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1answer
271 views

Amplify Raspberry Pi Zero W Audio with 60s Tube amplifier circuit

First of all, thank you for taking a look at my question. Electronics is not my field of expertise, and I have found myself a bit stuck. I have been restoring some old 50s and 60s tube amplified ...
3
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1answer
308 views

Ultra low power audio recorder

I'm trying to design an ultra low power audio recorder, in order to monitor ground noise in rural areas. The circuit I'm working on is based on a microcontroller (STM32L100RC) and an audio codec (...
3
votes
1answer
512 views

How would a transistor's hFE affect a phase shift oscillator?

I have a phase shift oscillator circuit from a drum machine that I would like to reproduce as faithfully to the original as possible. My problem is that the 40 year old design uses a transistor (...
2
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0answers
29 views

Summing Audio Channels

I’m trying to sum my car stereo output. Factory output has bass on one output and mid and tweeter on another output giving me 2 channels for left and 2 channels for right. Ideally I’d like to sum ...
2
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0answers
39 views

Strange leak problem in simple tone control circuit

I built the following circuit (physically): V1 is my audio signal and the circuit is a simple tone and volume control. When both the volume and the tone pot are turned all the way down (so each wiper ...
2
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0answers
313 views

Simple MM Phono Preamp Design

I'v found myself in need of a new preamp for my turntable (the one built into my power-amp went out with a bang and tripped the breaker!). I'm using a moving magnet type cartridge with output around ...
2
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0answers
187 views

How to connect Electret Microphone module and OPAMP?

I am trying to build a circuit that gets electret microphone input and maps into 0-1V for utilizing in ADC. The microphone module suggests using such circuitry When I tried that circuit and talked ...
2
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0answers
121 views

Designing an audio amplifier, problems with bandpass filter

I am trying to build a Audio amplifier for a university project, I think that most of my circuit is done but I have an issue with my filter as my sine signal is not symmetrical after filtering to ...
2
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0answers
87 views

High SNR FM demodulation

So I need to demodulate the FM signal from a sensor with highest SNR possible, at least 70-75 dB. IF is 10.7 MHz, max. deviation is 200 kHz but I can change those values if needed. Baseband signal ...
2
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0answers
130 views

How to connect a MEMS Microphone Breakout - INMP401 to a RN-52 bluetooth module?

I intended to use a INMP401 (MEMS MIC) to capture audio and stream it via bluetooth using an RN-52 bluetooth module (RN-52). The RN-52 has inputs for differential +- signals. The INMP outputs ...
2
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0answers
176 views

Identifying Noise in 12AU7 Based Headphone Amplifier

I've been working on making a tube based headphone amplifier as a fun personal project. The amplifier is based around this 12AU7 vacuum tube. The project for the most part is following this existing ...
2
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0answers
226 views

Can I replace electret microphone with audio connector and expect similar results (sound levels)?

Last night I built a circuit that allows me to obtain sound via a SEED Grove Sound Sensor and input it into my MKR Zero for frequency analysis. It's as simple as this: simulate this circuit – ...
2
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1answer
555 views

Dolby HX PRO implementation on existing tape recording deck

I'm experimenting the implementation of Dolby HX PRO's IC into an old stereo Fostex tape deck to improve high frequency and headroom capabilities. HX PRO works as a dynamic processor with the BIAS ...
2
votes
1answer
182 views

Can I connect a MEMS mic directly to this spectrum analizer chip?

I have a ICS-40181 MEMS mic and want to do basic spectral analysis using the popular MSGEQ7 chip for the purpose of a sound reactive project. Can I simply connect one into the other (with cap/res as ...
2
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0answers
62 views

Audio Sampling for Reactive Lighting

I'm trying to work on a reactive lighting project and I'm confused about a couple topics when it comes to sampling audio. I want to be able to have RGB reactive lighting controlled by a ...
2
votes
1answer
203 views

fixing the amplifier in an old arcade machine

I just joined and need help. I'm trying to fix the amplifier in my Chicago coin speedway arcade machine. It basically works but it has a bad hum in it. I did replace a couple capacitors that were ...
2
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0answers
308 views

Op-amp circuit saturates to negative rail and only passes positive side of input

I've been working on a spring reverb driver circuit, based mostly on figure 5 from this site: https://sound-au.com/articles/reverb.htm. While there's lots of information on the how of the circuit, ...
2
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0answers
280 views

Dual antiphase electret mic preamp topology

I am currently trying to make a preamp for an electret mic pair, which are placed physically in antiphase. The main idea is to subtract one mic's signal from another and therefore boost the signal ...
2
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0answers
2k views

Why do some audio amplifiers connect the power ground to the signal ground?

Trying to add a MIDI synthesizer & speakers to a keyboard here. Here's the schematic: simulate this circuit – Schematic created using CircuitLab But I was getting annoying crackling and ...
2
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0answers
551 views

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 ...
2
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0answers
1k views

HTC 10 DAC/amp specifications

I'm going to be doing a final year project revolving around music production and DACs are pretty important. Not going to go into detail (unless this question requires it) what the project is but I ...
2
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0answers
82 views

Audio: Camera activated external microphone

I want to build a relay circuit that turns on an external microphone (powered by an internal 9V battery) when a connected camera is turned on (a camera offering only 1V plugin power through a 3.5 mm ...
2
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0answers
2k views

Noise-cancelling headphone concept

Inexpensive noise-cancelling headphones use a single microphone located in a little lump between the plug and the earphones. They seem to work fairly well for ambient noises, but not for handling ...
2
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0answers
275 views

Linear vs. Audio Taper for RC Network

I'm building a distortion pedal and I was wondering which tapers to use for which potentiometers in the tone control section. I normally design my own circuits, but I'm going by someone else's ...
2
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0answers
278 views

Troubleshooting audio output on Nexys 2 (FPGA)

I've recently purchased the PMOD AMP1 module from digilent for use with my Nexys 2. When I program the demo project and plug headphones or speakers on the headphone output I can hear a barely audible,...
2
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0answers
2k views

Convert a wired headset to a wireless one

new to the board and not caught up with current technology, but I can handle myself when it comes to soldering and small electrical appliances. I have a headset that I really love, but the wire ...
2
votes
1answer
141 views

How does the center tap terminal work in Knowles Speakers ED series?

I would like to understand how the center tap terminal work in miniature speakers. I can see in the datasheet that a positive going voltage relative to this center tap can lower the output volume but ...
1
vote
1answer
60 views

How does the Yamaha DX7 digital analog converter work?

The Yamaha DX7 keyboard seems to have a quite sophisticated DAC and I wonder how it works. It is mostly specified as 12-bit DAC running at a sampling rate of 50kHz, but this doesn't tell the whole ...
1
vote
1answer
66 views

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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0answers
33 views

High pass filter that locks voltage at certain amount until frequency is reached

I have a sine wave that is biased at about 1.5V DC. I want to create a high pass filter that allows any frequency through greater than 4000Hz. Want I want my high pass filter to do is to be at 1.5V ...
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0answers
97 views

Make audio signal go only one direction

I have a circuit in my car which emulates the protocol the radio uses to communicate with a CD changer. The goal of the emulator is basically to make the radio open up it's audio channels. The circuit ...
1
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4answers
61 views

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. So I guess I would have : INPUT : 4 (computers) ...
1
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0answers
56 views

I need help with making a ground loop noise isolator

I want to build a ground loop noise noise isolator for 3.5 mm audio jack. After some research online I found multiple circuit diagrams centered around using audio 1:1 transformers to isolate each ...
1
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1answer
62 views

Problem connecting to Arduino with USB and audio

I have a project which uses an Arduino to detect tones generated by a laptop. The Tone Detector (TD) circuit is a very simple LM567 implementation designed to detect 10kHz. The circuit is powered by ...
1
vote
1answer
41 views

BJT reverse base-emitter voltage 1 Volts?

Using the multimeter diode setting in a powered down circuit, on the TR6 transistor (BC548), the forward B-E and B-C voltages are ~0.7 V, reverse B-C is OL but reverse B-E is 1.08V. Does this mean the ...
1
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1answer
60 views

Measuring BJT voltages in circuit?

Using a multimeter's diode setting I see that both the base-emitter and base-collector voltages of a transistor in a powered down circuit are 0.67Vm, while reversing the probes shows OL. Voltage ...
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1answer
56 views

How can I calculate low and high frequency in my circuit?

How can I calculate low and high frequency in my circuit? I have used an 8-ohm speaker.
1
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1answer
60 views

Trying to control vintage amplifier (TEAC A-H500) with Raspberry Pi - what's the communication protocol? 8-bit bus?

I'm trying to control my vintage amplifier from Raspberry Pi - I want to create a nice little Spotify streamer that on playback start will automatically turn on the amplifier and set the input ...
1
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0answers
34 views

Common ground for subwoofer-out

I have a Sony Sony DSX-A110u which is a car stereo having 4*55W Speaker out and a Sub-woofer out. The subwoofer-out port it a female RCA jack. which looks like this - I am using the sub-woofer out ...
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0answers
23 views

Troubleshooting adding a bluetooth receiver to my intercom system

I have a Nutone IMA 4406 intercom system with several intercoms throughout the house. I am interested in wiring a Bluetooth receiver to its Auxillary line in connection so that I can stream music ...
1
vote
1answer
41 views

Noise and weird looking audio waveform when recording directly from melody generator output

I am trying to record the output of an melody generator IC with my digital recorder. I connected the circuit like the image below, and it sounds almost okay, but there is a high frequency noise in the ...
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0answers
54 views

How to prevent noise when connecting “speaker out” of SIM800L to audio mixer?

Aim I'm trying to build a device to be used for call center agents. They could make calls via this device, which could be connected to a PC to be able to record this conversation. Solution Build ...
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1answer
54 views

Understanding LM386 amplifier component selection

I am a computer engineering student and I still struggle to understand electricity. I am doing an audio amplifier project and would like to understand the math behind why these capacitor/resistor ...
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0answers
32 views

PS4 Party linked to Discord | Jack output to microphone input (line signal to phono signal) | Audio

I would like to connect an audio jack output (audio usb card on PS4), to the microphone input of a phone, and reverse the audio output of the phone to the audio input (microphone) of the usb card. ...
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0answers
37 views

Separation of channels in simple audio LED VU meter

I'm trying to build a very simple VU meter based on LEDs and transistors. I used this tutorial as a base - basically I copied the LED array setup but replaced the input with full bridge rectifier. My ...
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1answer
44 views

How to interface a microphone to an I2S input to use HFP

For my group's SDP/Capstone we are doing a bluetooth headset of sorts. We are using a CYW20706 SoC from Cypress. Specifically, we are using a this CYBT-343026-01 Cypress module whch includes that ...
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0answers
137 views

IC Protector in AV Receiver (ICP-N15)

I'm fixing a Denon AVR-788 AV receiver that won't boot but would turn on with the light in front blinking red. Naturally, I looked to the Service Manual (link goes to schematic) and started following ...
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0answers
35 views

Diagnosing USB Power bank shut-off on load application

I'm trying to create a small bluetooth boombox-style speaker, but am having trouble powering the device from a USB battery bank. Fundamental Problem: The power bank "shuts off" as soon as the load is ...
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0answers
71 views

“Anti-Pop” Circuit For Guitar Pedals

I want to add resistors to my guitar pedal circuit to remove any popping noise when switching the pedal on and off (actually on and to bypass). Found an article about that, but the values for ...

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