App note from Microchip about wireless multi-speaker connectivity solution. Link here (PDF) Microchip’s Multi-Speaker Bluetooth Audio solution utilizes Microchip proprietary technology to connect a master speaker to one or multiple slave speakers through a modified Bluetooth protocol. Multi-speaker functionality is implemented using Microchip’s BM6x family of modules. One (master) speaker can either be connected to […]
Tag Archives: audio
App note: Loudspeaker characterization and compensation
Using DSP and ST’s Tune software to compensate for a flatter response on speakers discussed in this app note from ST Microelectronics. Link here (PDF) The application note describes how to measure and analyze the performance of a loudspeaker and how to compensate the frequency response using the ST Speaker Tune software, a tool available […]
Oscillatoscope2e
Oscillatoscope2e @ gieskes.nl Oscillatoscope2e is a eurorack version of Oscillatoscope2. It is the same, only the audio output is DC coupled and 10v peak to peak. For Oscillatoscope2 see here. Check out the video after the break.
Dual Mono AK4493 DAC (MK II)
An update on Dual Mono AK4490 DAC project we covered previously: Since I was going to update the PCB design, I thought I might as well improve on as much as I could. So, the new board would: *Include a new reclocking solution. I went for the best specc’ed chip out there, the famous Potato […]
Open source hardware ESP32-ADF
Here’s an open source hardware development board for Espressif audio development framework, the ESP32-ADF, from Olimex: With ESP32-WROOM-B module with 8MB RAM and 4MB of Flash, two microphones, two 3W speakers, codec, amplifier, Lipo charger, USB with programming, Audio 3.5mm jack, ESP32-ADF board offers everything you need to start playing with Espressif Audio Development Framework. Check […]
Making a SPL dB meter
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 lecture on how sound travels […]
App note: Active filtering in automotive audio applications
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 (op amps) are one of […]
Transistor radio series: the AF power amp
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 on the PA audio stage. […]
6 channel speaker selector
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. Using this listener can select […]
Ultrasonic audio transmitter and receiver system
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. Check out the video after […]
Arduino controlled Dual Mono AK4490 DAC (part 3)
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 discreet single-ended class-A output stage, […]
Game audio for the ESP32
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 that way. I ended up […]
Arduino controlled Dual Mono AK4490 DAC (part 1)
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 have a very solid, low […]
App note: BH45F0031 Earphone jack communication
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 can directly transmit data and […]
100W AF dummy load
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 4 resistors are mounted on […]
App note: Class D audio amplifier basics
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.
App note: How to pick a click-and-pop suppressor
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.
App note: Measuring a loudspeaker impedance profile using the AD5933
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 the impedance profile of the […]
Open hardware DSP platform
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 amp, or a fully fledged […]
App note: The 2-Channel serial audio interface: A tutorial
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 naming conventions used within the […]