Posts Tagged ‘audio’

Making a SPL dB meter

Monday, July 1st, 2019

Shawon Shahryiar over at Embedded Lab shared a how-to on making a SPL dB meter: Sound needs a medium for propagation or travel. It can’t travel in vacuum. Normally air is that medium but sound can also propagate in liquids and other states of matter. I am not going to...

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Posted in DIY, how-to | No Comments »

App note: Active filtering in automotive audio applications

Sunday, November 18th, 2018

App note from Texas Instruments on isolating DC and high frequency noise in audio using their automotive op amps. Link here (PDF) Phone calls, emergency alerts, and music are just a few of the reasons that a high quality audio system is vital in automotive infotainment and clusters. Operational amplifiers...

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Transistor radio series: the AF power amp

Wednesday, June 6th, 2018

Vasily Ivanenko @ QRPHB writes, "I sought a low distortion, single supply, AF power amplifier for my transistor radios. I’ll present my experiments, some musings, test equipment and a reference to some wonderful books & their wise author. Sadly, some amateur radio receiver builders diligently craft their RF stages, but skimp...

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6 channel speaker selector

Monday, April 30th, 2018

Dilshan Jayakody published a new build: If you are an audio enthusiast and if you have multiple audio systems and speakers, you may definitely need to have a speaker selector switch. These switches allow you to route a audio signal through a switching system and distribute it to various speakers....

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Posted in DIY, PIC | No Comments »

Ultrasonic audio transmitter and receiver system

Saturday, March 10th, 2018

An ultrasonic audio transmitter receiver system from Vinod S. Hi all, this is another mad project.  Aim of the project is to transmit laptop audio via ultrasound to few meters and then receive it and demodulate it and playback the audio on a speaker. See the full post on his blog....

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Posted in AVR | No Comments »

Arduino controlled Dual Mono AK4490 DAC (part 3)

Tuesday, March 6th, 2018

Here’s the part 3 of Dimitris' Arduino controlled Dual Mono AK4490 DAC project we covered previously: Following up on Part 2, it’s time to talk about the output stage. This output stage is the brainchild of my friend Kostas, all I did was lay out the PCB. It is a fully...

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Posted in Arduino | 2 Comments »

Game audio for the ESP32

Monday, February 19th, 2018

ESP32 game audio at Buildlog.Net blog: I have been working on some games for the ESP32 and needed some decent quality audio with a minimum number of additional components.  I was bouncing between using the DAC and using the I2S bus. The DAC requires less external parts, so I went...

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Posted in library, wireless | No Comments »

Arduino controlled Dual Mono AK4490 DAC (part 1)

Thursday, November 16th, 2017

This article is the first of a series detailing the design and build process of an Arduino controlled Dual Mono AK4490 DAC by DimDim: The design goal was to do a dual mono design so as to maximize SNR and channel separation. A 4-layer PCB design was chosen so as to...

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Posted in Arduino, DIY | No Comments »

App note: BH45F0031 Earphone jack communication

Sunday, February 26th, 2017

Holtek's App note about their audio to digital signal converter chip BH45F0031 that together with an phone app, communication via audio phone jack is possible. Link here (PDF) The BH45F0031 is a Flash type 8-bit high performance RISC architecture microcontroller, which is designed for smart phone headset interface applications that...

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Posted in app notes | 1 Comment »

100W AF dummy load

Friday, November 11th, 2016

Dilshan Jayakody has published a new build: This is a quick post to showcase 100W 4 channel AF dummy load which we build to test the output stages of audio power amplifiers. This dummy load use 4, 8Ω 100W wire wound resistors which are available in eBay. In this unit all...

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Posted in DIY | 2 Comments »

App note: Class D audio amplifier basics

Sunday, September 11th, 2016

Class D audio amplifier an efficient amplifier by Infineon Technologies, Link here A Class D audio amplifier is basically a switching amplifier or PWM amplifier. There are a number of different classes of amplifiers. This application note takes a look at the definitions for the main classifications.

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App note: How to pick a click-and-pop suppressor

Sunday, September 11th, 2016

Audio noises click-and-pop suppression method from Maxim. Link here (PDF) This application note presents the MAX9890 and MAX9892 which use different approaches to remove audible click and pop from headphones. Each device is uniquely suited to different applications.

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App note: Measuring a loudspeaker impedance profile using the AD5933

Sunday, August 21st, 2016

An application note from Analog Devices about AD5933, this provides a low cost substitute to expensive test equipment like signal generators, oscilloscope and voltmeters in getting the speaker's impedance profile. Link here (PDF) This application note describes a circuit architecture using the AD5933 that allows the system designer to measure...

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Open hardware DSP platform

Wednesday, August 10th, 2016

 Open source hardware digital signal processing platform from Paul Janicki: The open hardware DSP platform is a range of small boards that can be plugged together to give you a flexible platform for processing all sorts of audio signals. If you want a simple crossover, a custom USB soundcard and headphone...

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App note: The 2-Channel serial audio interface: A tutorial

Sunday, May 1st, 2016

A pretty older application note about the serial audio interface by Cirrus Logic. Link here (PDF) It may come as a surprise to those trying to make their initial investigation into audio systems design that there is a de-facto standard for transferring audio data within a system. Despite the differing...

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App note: The LM4935 headset and push-button detection guide

Sunday, May 1st, 2016

Another headset plug-in detection from Texas Instruments. Link here (PDF) The headset detect circuitry can differentiate between mono, stereo, mono with microphone, and stereo with microphone headsets. It can operate while the LM4935 is placed into low current standby mode, which promotes extended battery life. In standby mode, it consumes...

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Posted in app notes | 1 Comment »

App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection

Sunday, March 27th, 2016

App note on Cirrus Logic's WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF) This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA...

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flip-flop/BCF project

Thursday, February 11th, 2016

Ray over at the diyAudio forum has been working on his flip-flop/BCF project: I've just finished a project to roll up the developments into a more 'finished' build, feeding the balanced outputs from the flip-flop board into a Broskie BCF buffer stage. I'm using Nicks MJ Statistical Regulator for the B+ and...

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Replacement LED driver for AN6877

Friday, December 18th, 2015

Dilshan Jayakody writes: AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on many audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quiet difficult. The circuit described in this article is design to replace AN6877...

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Posted in LEDs | 1 Comment »

Audio multiplexer with integrated amplifier

Wednesday, December 2nd, 2015

Audio multiplexer with integrated amplifier project by Matt Winslow, built as a capstone project for his masters in EE: This project is to act as a central hub for switching between audio sources and listening devices. Multiple audio sources can include a phone, computer, TV, etc. The listening devices can...

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Posted in DIY | 3 Comments »

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