Speaker: Matei Alexandru Costea, University of Derby
Wed 12th February 12:00 – 13:00 UK time. This seminar will be held in person in Gilbert 1 and you can join us online via Microsoft Teams.
Abstract
The aim of the research is to create a drone-carried microphone array system capable of collecting high-quality audio measurements faster and from more locations than a standard microphone manually positioned by an engineer.
An array system using high-quality microphone capsules in an omnidirectional arrangement has been proposed to perform the localisation of problematic sound reflections. Impulse response measurements will be taken by the system to perform the acoustical analysis of the room (Cox, 2024).
Three physical noise suppression methods have been proposed. First, inverting the orientation of the motors into a pusher configuration can reduce the broadband interaction noise between the airflow and the support arm (Sharma & Atkins, 2019). Second, surrounding the motor with a duct can reduce the number of tip vortices that cause tonal noise (Pereira, 2008). Third, a propeller with vertically and horizontally offset blades is hypothesised to reduce the overall noise by reducing the disk solidity and wake turbulence noise (Akiwate et al., 2022). Furthermore, digital noise cancellation algorithms could improve the signal quality using machine learning or neural networks (Wang & Cavallaro, 2020).
A hexacopter drone has been built capable of carrying the array system. Acoustic measurements of the unmodified drone show 85-90 dB at 2m, while the drone was hovering around 1.5m height. Four 3D-printable duct models were designed and will be tested for acoustical qualities. Applying the physical noise suppression methods is expected to reduce the overall noise by 20+%.
This tool could improve our understanding of room acoustics and help deliver better, safer listening experiences to audiences and engineers. The system could also help in maintaining large-scale permanently installed sound systems for public announcements.
Biography
Matei is currently a third-year PhD student in the Audio Engineering field. In his thesis titled ‘Autonomous Acoustical Analysis of Electroacoustic Systems Using Unmanned Aerial Vehicles’, Matei is trying to design a multi-channel spherical microphone array to be installed on a drone used to measure acoustical spaces and provide real-time information for calibrating loudspeakers. The research also involves finding and applying suitable drone noise reduction methods. Before starting the PhD, he worked as a microphone technician for Solotech, the UK branch of one of the largest live sound companies in the world, and as a demonstrator for Birmingham City University in the Acoustics and NIME modules. Matei holds an MSc (Distinction) in Audio Engineering from the University of Derby and a BSc (Hons) in Sound Engineering and Production from Birmingham City University, and has acted as a student representative for his courses throughout his time in University.