Audio category

Tune Your String Instruments Perfectly With Roadie Tuner

Roadie Tuner is a dream come true for guitarists! The automatic ring tuner, that is quick, easy to use, and three times more accurate than the human ear, is dedicated to beginner guitarists who are almost always frustrated with not knowing how to tune their guitar. This ultimate musician’s tool works on all string instrument to fine tune them in seconds, including bass guitars.

Roadie Tuner pairs with a free app on your smartphone, iPod or tablet through Bluetooth 4.0 smart. All the audio processing happens on the smartphone which sends tuning commands to Roadie. You can choose from a list of alternate tunings or you can easily create your own.

You can set up a profile for your instrument in Roadie Tuner app and it will track its maintenance history. Thus, it will inform you of the quality of your strings and recommend restringing as soon as the tone quality deteriorates.

Roadie tuner team had just launched their second version of this amazing product, Roadie 2. The new about this tuner the fact that it is  fully standalone and uses vibration detection to tune in even the noisiest of environments. Thus, no need to be paired with a mobile app anymore to tune your instruments.

Below are Roadie 2 technical specifications:

  • Metallic gearbox: Built with a 380:1 gear ratio motor that insures Roadie 2 will turn those rusty pegs for you. The motor can turn in micro-movements to achieve unparalleled precision.
  • Battery:Powered by a rechargeable Lithium Ion battery (included). Lasts 1 month on a single charge. Includes a battery indicator to show you how much juice is left.
  • USB-C: With a charging cable included.
  • Built-in user interface: For easy selection of instruments and tunings.
  • Bluetooth 4.0 low energy
  • Haptic feedback: When a string is in tune, Roadie will give you a little shake to move on to the next string.
  • OLED screen Invisible when off, lights up beautifully as soon as you turn Roadie 2 on.
  • Knob interface: Intuitive and fast to scroll through your instruments and tunings.
  • Weight: Product weight: 3.2 ounces. Shipping weight: 9.9 ounces.
  • Product dimensions: 3.4 x 3.0 x 1.0 inches.
  • Material / Color:Plastic / Black.

“I think the concept is fantastic and I would be thrilled to have one of these because I actually play twelve string guitars. You don’t know how bloody difficult it is to keep a twelve string in tune” – Spike Edney, Queen

More details about extra features within the Roadie Tuner app, the product versions and more are available at the Kickstarter campaign the team had launched 2 days ago. Within only 3 hours, the campaign had achieved its goal and it is already 300% funded. Early bird offers still has 8 hours to go, you can pre-order your own Roadie for $79! Also check out the official website for more information.

Tiny Professional Microphone Preamplifier

The board has been design around INA217 low distortion, low noise instrumentation amplifier. The INA217 is ideal for low-level audio signals such as balanced low-impedance microphones. Many industrial, instrumentation, and medical applications also benefit from its low noise and wide bandwidth. Unique distortion cancellation circuitry reduces distortion to extremely low levels, even in high gain. The INA217 provides near-theoretical noise performance for 200Ω source impedance. The INA217 features differential input, low noise, and low distortion that provides superior performance in professional microphone amplifier applications. An OPA2137 op-amp used as a feedback to eliminate the offset voltage. Phantom power is not part of the circuit its just for reference.

Features

  • Supply Dual +/-15V DC
  • Output Unbalance Single Ended
  • PR1 Gain Adjust G=1+10000/Rg PR1

Tiny Professional Microphone Preamplifier – [Link]

RELATED POSTS

High Performance Stereo Audio Amplifier using LM3886

The LM3886 is a high-performance audio power amplifier capable of delivering 68W of continuous average power to a 4Ω load and 38W into 8Ω with 0.1% THD+N from 20Hz–20kHz.

The performance of the LM3886, utilizing its Self Peak Instantaneous Temperature (°Ke) (SPiKe) protection circuitry, puts it in a class above discrete and hybrid amplifiers by providing an inherently, dynamically protected Safe Operating Area (SOA). SPiKe protection means that these parts are completely safeguarded at the output against overvoltage, under voltage, overloads, including shorts to the supplies, thermal runaway, and instantaneous temperature peaks.

The LM3886 maintains an excellent signal-to-noise ratio of greater than 92dB with a typical low noise floor of 2.0µV. It exhibits extremely low THD+N values of 0.03% at the rated output into the rated load over the audio spectrum, and provides excellent linearity with an IMD (SMPTE) typical rating of 0.004%.

Note : Amplifier Requires a Large Size Heat sink

High Performance Stereo Audio Amplifier using LM3886 – [Link]

The SilentSwitcher, A Quiet Mains-free Power Supply

Audio projects become smaller over time with the rapid advancement of technology. A traditional power supply is still considered large compared to audio projects size constraints and it may not fit such delicate applications that need to deliver a good sound with zero noise.

Jan Didden, audio specialist who is known for his own publications Linear Audio, has came up with a new idea that can help in perfecting audio projects. The SilentSwitcher is a 55 x 31 mm special power supply module designed to supply clean power to high-end analog and digital audio circuits.

29c89cc9e7f7dbc67843d2b414d056f6_original

“One goal of this power supply that it doesn’t need to connect to the mains, you can use it with a USB charger or with a power bank… All problems with ground loops and mains born noise are not existing”- Jan Didden, the designer of The SilentSwitcher

The SilentSwitcher uses a combination of switching and linear regulators to generate a stable and noise-free supply voltage. The module can be powered from a 5V USB adapter, or from a 5V power bank for complete isolation. It delivers ±150 mA and a choice of 6V, 5V or 3.3V at 0.5 A to benefit most of your applications. The absolute maximum input voltage is 12VDC but in normal operation it is preferable to limit it to 10VDC.

Output specifications:

  • Outputs (analog): +15 and -15 VDC at 150mA* each;
  • Output (6/5/3.3V): selectable 6, 5 or 3.3 VDC at 0.5A*;
  • Output noise (6/5/3.3V): less than 1mV broadband
  • Output impedance (analog): less than 10mΩ (+15V) and 80mΩ (-15V) at 20kHz
  • Output impedance (6/5/3.3V): less than 3mV drop with 100mA current step.

15V output at 150mA are provided thanks to the very low noise linear regulators of Texas Instruments TPS7A47, TPS7A33 that suppress all the noise from the switching regulator by a factor of one thousand even at 1 Megahertz. Such chips have driven zero noise to switcher technology and have shown incredible quiet and low noise performance.

Jan Didden talking about his product

The well designed board will help in keeping all elements quiet and avoiding excess radiation. There are 2- and 3-pin headers on the PCB to connect the load, and a 2-pin header for an On/Off switch. The connection to the 5V source is through a B-type USB connector or a standard 2-pin screw-type connector block. You can mount the PCB on the back of your enclosure with a hole cut out for the USB-B – no further input wiring required.

The SilentSwitcher Connections
The SilentSwitcher Connections

This power supply will be a great companion for your project! No need to think about wiring or transformers, and you won’t face any issues like mains hum or mains earth loops.

The SilentSwitcher is live on a Kickstarter crowdfunding campaign and there are only few hours left to go! You can get your own SilentSwitcher for $59 and you will receive a fully assembled and tested board.

More details are provided at the campaign page and at Linear Audio website.

LTC3623 – Switching regulator doubles as Class-D audio amplifier

20160822150557_ltc3623-2

Clemens Valens @ elektormagazine.com discuss about LTC3623 switching regulator which can be used as Class-D Audio Amplifier.

Sure thing, Elektor has published several designs of adjustable power supplies based on switching regulators, so we know that doing this properly in a reproducible way and without making things overly complex requires some serious head scratching. The anxiety may be reduced vastly though by a new adjustable synchronous buck regulator which uses a single resistor to set its output voltage anywhere between 0 and 14.5 volts. Using the device is very simple; you can even use it as an audio amplifier.

LTC3623 – Switching regulator doubles as Class-D audio amplifier – [Link]

Laser for sending music over a distance

Light is a very popular means of communication. Today, optical fiber communication is the backbone of telecommunication and internet. Light is guided through a fiber optic cable in such systems to achieve low-attenuation and high speed data transmission. Question is: Is it possible to use light for communication without a guiding medium? The answer is positive. Because of the highly collimated nature of the laser beam, it is feasible to use a laser output to transmit information without a guiding medium even in daylight, provided that the line of sight occurs between the sending and receiving units.

Armand & Victor from DIY Experiments Youtube channel illustrates a very simple example of modulating a laser diode output with an analog audio signal and sending it over a distance of more than 400 meters. The laser diode used in this project was of 250 mW capacity, which is ~ 100 times more powerful than a regular laser pointer. A single-transistor class-A amplifier circuit was used to amplify the audio input signal prior to use it for modulating the laser output light. A 1:25 turn ratio transformer is used as a coupling device between the audio and the laser module. The transformer is necessary to ensure only the AC variations (and blocks any DC component) in the audio signal will modulate the laser beam.

Circuit setup for modulating Laser with an audio signal

Circuit setup for modulating Laser with an audio signal

On the receiving end, the audio is reconstructed back by aiming the modulated laser beam at an array of four mini solar panels. The solar panel output voltage varies according to the signal variation contained in the laser and is directly fed to a high power (250W) guitar amplifier. The audio quality was quite remarkable for such a simple setup. Check out the following demo video of this project:

RELATED POSTS

Whisper Trigger – An Ultra-low Power Voice Detector

For long period of time, we were using our muscles and bodies to control various machines. However, with the growth of technology, things became much easier. We moved to the use of keypads and buttons to get jobs done. Today, touchscreens have appeared and made everything very simple to use. But we did not get enough, and the near future will be for the voice commands.

Using voice commands implies the need to use detection systems and circuits, which must provide high accuracy results, reliable at both near and far distances, not affected by noise, simultaneously sensitive, fast, and also have low power consumption. Power consumption is very important factor nowadays, especially with the application of Internet of Things (IoT) devices which are powered using batteries and have to work for long time.

Most of current solutions for voice recognition use digital signal processors (DSPs) connected with A/D converters and they work in permanent wake mode which make them consume high amounts of  power in case of IoT applications and smartphones.

The conventional Approach
The conventional Approach

Dolphin Integration, a French corporation works on enabling low-power Systems-on-Chip and provides a solution called Whisper Trigger, an ultra-low power voice detector with outstanding performance of detection, enabling wake-up voice acquisition and recognition when needed. In comparison with other devices, this technology reduces power consumption by 80-90%. It consumes only 20 µA, and needs just 1 millisecond to wake up.

voice_detect_2

Dolphin Integration provides also another solution for text recognition and detection of keywords, the Microelectromechanical System (MEMS) which should be connected to DSP and circular buffer to perform the process of conversion, decimation and filtering.

dolphin-greenmems-microphone

Source: Elektormagazine

Low noise Mini Electret Microphone PreAmplifier

img_5974

The single supply microphone pre-amplifier amplifies the output signal of an electret capsule microphone to audio line levels. An op amp is used as a trans-impedance amplifier to convert the output current from the microphone in to a signal level voltage. The circuit works with 9V so it is good choice for battery operated systems.

Features

  • Supply 9V DC
  • Current Approx. 3mA
  • On Board Microphone
  • Very thin and narrow PCB

Low noise Mini Electret Microphone PreAmplifier – [Link]

RELATED POSTS

How to Build a Class-D Power Amp

Thumbnail

Cezar Chirila @ allaboutcircuits.com shows how to build a Class-D amplifier which has amazing efficiency.

What is a Class-D audio power amplifier? The answer could be just a sentence long: It is a switching amplifier. But in order to fully understand how one works, I need to teach you all its nooks and crannies.

How to Build a Class-D Power Amp – [Link]

RTL8710 Is a New ESP8266 Competitor

RTL8710

In the last two years, ESP8266 was the Wifi Chip/Module which dominated the market of hobbyists, even a lot of commercial products use ESP8266, due to the low price, ease of use and large community around ESP8266.

RTL8710 is a Wifi network solution from the Taiwanese Company Realtek. It can operate independently, or as a slave to another MCU host. The same way of ESP8266.
RTL8710 has a built-in ARM Cortex M3 MCU at 166 MHz, 1MB flash and peripherals like UART, PWM, I2C, GPIO and PCM, a more detailed comparison is shown in the  table bellow:

Table courtesy of cnx-software
Table courtesy of cnx-software

If you like to have a quick hands on RTL8710, then you can order a development board for RTL8710.

RTL8710DK

Via: cnx-software