AES Dublin 2019
Engineering Brief EB03
EB03 - Microphones and Circuits
Thursday, March 21, 16:00 — 17:15 (Meeting Room 3)
Joerg Panzer, R&D Team - Salgen, Germany
EB03-1 Analysis of Beam Patterns of Super Directive Acoustic Beamformer—Adam Kupryjanow, Intel Technology Poland - Gdansk, Poland
In this brief beam patterns of a super directive acoustic Beamformer were presented. The analysis was done based on the recordings made in diffuse far field environment. State of the art MVDR (Minimum Variance Distortionless Beamformer) was utilized as representative of super directive Beamformer. Two types of uniform microphone arrays were investigated: linear and circular. Experiments were performed for various number of microphones in the arrays, i.e., two, four, six, and eight.
Engineering Brief 504 (Download now)
EB03-2 Configuration for Testing Intermodulation of Ultrasonic Signals in the Microphone Path—Dominik Stanczak, Intel Technology Poland - Gdansk, Poland; Jan Banas, Intel Technology Poland - Gdansk, Poland; Jedrzej Prysko, Intel - Gdansk, Poland; Pawel Trella, Intel - Gdansk, Poland; Przemek Maziewski, Intel Technology Poland - Gdansk, Poland
The paper presents a comparison of five configurations used to test intermodulation of ultrasonic signals. All five require the use of ultrasonic loudspeakers in an anechoic, low-noise environment. Settings vary in the number and type of digital-to-analog converters and loudspeakers, as well as connection types. Best configuration introducing a small amount of self-intermodulation for the high power of the ultrasonic signals is identified.
Engineering Brief 505 (Download now)
EB03-3 Considerations for the Next Generation of Singing Tutor Systems—Behnam Faghih, Maynooth University - Maynooth, Kildare, Ireland; Joseph Timoney, Maynooth University - Maynooth, Kildare, Ireland
Recently software systems have been proposed to accelerate the progress of singing beginners. The basics of these systems are: the pitch of the sung notes is detected and algorithmic errors removed. Then, an alignment is made with a melodic ground truth, often as a midi representation, using techniques including Dynamic Time Warping and Hidden Markov Models. Although results have been reasonable, significant drawbacks to these alignment schemes include how a “musically acceptable” alignment can be identified, dynamic singer behavior, multiple repeated notes, and dealing with omitted or extra notes. To this end an improved singing analysis system structure is proposed that includes psychoacoustic models and intelligent decision making. Justification is given along with a description of a structured evaluation procedure.
Engineering Brief 506 (Download now)
EB03-4 Control Techniques for Audio Envelope Tracking—Robert Bakker, NUI Galway - Galway, Ireland; Maeve Duffy, NUI Galway - Galway, Ireland
One of the main applications for class-D audio amplifiers is portable or battery-operated devices such as Bluetooth speakers, smartphones, car stereos, etc. These devices often use a boost converter to increase the battery voltage to a suitable level to achieve the desired power output. The use of envelope tracking (ET) has been shown to significantly improve the efficiency of a class-D audio amplifier, particularly at lower power levels. However, modulating a boost converter to provide envelope tracking at a high bandwidth is complicated due to the right half-plane zero in its transfer function. This paper discusses the effect of envelope bandwidth on the overall system performance, and how it affects the control of the boost converter. It also discusses the different control methods for boost converters, and variations of this type of DC/DC converter.
Engineering Brief 507 (Download now)
EB03-5 Sound Synthesis Using Programmable System-on-Chip Devices—Larry Fitzgerald, Maynooth University - Maynooth, Kildare, Ireland; Joseph Timoney, Maynooth University - Maynooth, Kildare, Ireland
An approach to building analog synthesizers may be found by exploiting a new mixed-signal technology called the Programmable System-on-Chip (PSoC), which includes a CPU core and mixed-signal arrays of configurable integrated analog and digital peripherals. Another approach is to exploit a System on Chip (SoC) comprising an ARM-based processor and an FPGA. Two synthesizers were built and evaluated for sound quality and difficulty of implementation. Each of the approaches produced a synthesizer of good sound quality. The mixed-signal approach was cheaper in both component costs and development time compared to the FPGA-based approach.
Engineering Brief 508 (Download now)