»Acoustical Tests and Measurements

MEZZOLaB is an independent acoustics laboratory providing material testing for both in-house research projects and for audio, acoustics, and construction industries. Real-size room acoustics measurements and building acoustics field tests for measuring airborne and impact noise transmission are held with high end acoustical test systems. In addition, highly specialized software tools licensed to MEZZO, aid designers in the prediction of acoustical quantifiers even in design phase of ongoing projects. Hardware and software systems of MEZZO Stüdyo provide our experts to acquire scientifically reliable test results in accordance with following ISO standards:

 

  • ISO 16283-1:2014 - Acoustics — Field measurement of sound insulation in buildings and of building elements — Part 1: Airborne sound insulation
  • ISO 16283-2:2015 - Acoustics — Field measurement of sound insulation in buildings and of building elements — Part 2: Impact sound insulation
  • ISO 16283-3:2016 - Acoustics — Field measurement of sound insulation in buildings and of building elements — Part 3: Façade sound insulation
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  • ISO 3382-1:2009 - Acoustics — Measurement of room acoustic parameters -- Part 1: Performance spaces
  • ISO 3382-2:2008 - Acoustics — Measurement of room acoustic parameters -- Part 2: Reverberation time in ordinary rooms
  • ISO 3382-3:2012 - Acoustics — Measurement of room acoustic parameters -- Part 3: Open plan offices
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  • ISO 10534-2:1998 - Acoustics — Determination of sound absorption coefficient and impedance in impedance tubes -- Part 2: Transfer-function method

 

» Kundt Tube for Acoustic Absorption and Transmission Loss

Kundt / TL Tubes (S.C.S) consist of a complete set of hardware and software tools, for measuring acoustical properties of materials as absorption coefficient, standard impedance, characteristics impedance and transmission loss as a function of frequency. The SCS9020B software works in conjunction with 01dB-Metravib software dBFA suite (RT) part acting as a server, using TCP-IP commands and consists in two parts: Absorption Index and Transmission Loss coefficient. Each of those has a different configuration setup specifically: . 'Kundt Tube' configuration represents the basic, standard system set up for absorption coefficient and acoustic impedance measurements (2 microphones - transfer function method), according to ISO 10534-2:1998. The sound absorption measurement is related to the capacity of materials to absorb, reflect and dissipate acoustic energy. . 'TL tubes' configuration represents the tube arrangement scheme, which allows Transmission Loss measurements (4 microphones method) The double tube set up of sound absorption and transmission loss measurements include small and large tubes. Small tube setup is composed of the small sized (Ø28mm) devices for acoustic properties measurements in the high frequency range (800Hz to 6300Hz), while large tube setup is made up of Ø100mm tubes for measurements in the low frequency range (50Hz to 1200Hz). For a full band frequency response test -either for sound absorption coefficient or transmission loss measurements- of a proposed material, minimum two samples with diameters of 28mm and 100mm should be supplied to MEZZOLab.

» DIRAC Room Acoustics Software Type 7841 v.4.1.

DIRAC is used for measuring a wide range of room acoustical parameters including Early Decay Time (EDT), Reverberation Times (T10, T20, T30), Strength (G), enter Time (Ts), Clarities (C30, C50, C80), Definition (D50), Early Lateral Energy Fraction (LF), Inter-Aural Cross-correlation Coefficient (IACC80), Speech Transmission Index (STI), Room Acoustics STI (RASTI) etc. Based on the measurement and analysis of impulse responses, DIRAC supports a variety of measurement configurations. For accurate measurements according to the ISO 3382 standards, internally or externally generated MLS or sweep signals through a loudspeaker sound source can be used. Speech measurements can be carried out in compliance with the IEC 6026–16 standard. MEZZOLaB adapts DIRAC for measuring the acoustics of an enclosure, measuring speech intelligibility, checking acoustics before and after modification, comparing acoustics of different rooms, comparing measurements to predictions (ODEON) and for research, development and education on acoustics. B&K 2250 Based Building Acoustics System This complete system of software and hardware provides MEZZOLaB team to hold building acoustics measurements including airborne, facade and impact sound insulation. The components of the system in hand of MEZZO Studio and brief descriptions are listed below.

» Building Acoustics Software BZ-7228

BZ-7228 software is a complete application package used with Hand-held Analyzer Type 2250 for measuring source and receiving room level spectra in field measurements. Having built-in pink and white noise generator is able to use impulse and interrupted noise methods. The package calculates the results in accordance with following ISO standards, ISO 16283-1:2014, ISO 16283-2:2015, ISO 16283-3:2016.

 

» PULSE Reflex™ Building Acoustics Type 8780

Type 8780 is the software package for post-processing and reporting of building acoustics measurements made with Hand-held Analyzer Type 2250. MEZZOLaB adapts PULSE for calculating building acoustics results, analysis/re-analysis of data, report generation and data archiving.

» BZ-7223 Frequency Analysis Software

BZ-7223 allows MEZZOLaB taking real-time measurements in 1/1(centre frequencies 8Hz to 16kHz) and 1/3 (centre frequencies 6.3Hz to 20kHz) octave bands. In each band there is a full and unrivalled dynamic range from the noise floor in that particular band to 140dB making a dynamic range generally in excess of 135dB. Spectra can be A-, C- or Z-weighted.

» Hand-held Analyzer B&K Type 2250-A

Type 2250 hand-held instrument platform provides MEZZOLaB to run a wide range of sound and vibration measurement applications. With mounted microphone B&K Type 4190 ZC-0032 Hand-held Analyzer not only enables data collection for room and building acoustics measurements but also facilitates environmental and workplace noise assessment, industrial quality control and product development. The Hand-held Analyzer is proper for the tough environment of field measurements working reliably in rain, dust, heat or frost. Type 2250 is a single-channel analyzer offering a range of optional software application modules including above mentioned Reverberation Time and Building Acoustics Software.

» OmniPower™ Sound Source B&K Type 4292-L

For airborne noise transmission measurements as well as measurement of room acoustics parameters, the sound source must radiate sound evenly in all directions to give reproducible and reliable results; therefore, the relevant building acoustics measurements standards require the use of an omni-directional sound source. Type 4292 satisfies the requirements of ISO 16283  and ISO 3382 standards. This omni-directional sound source uses a cluster of 12 loudspeakers in a dodecahedral configuration that radiates sound evenly with a spherical distribution. All 12 speakers are connected in a series-parallel network to ensure both inphase operation and impedance that matches the power amplifier.

» Power Amplifier B&K Type 2734-A

MEZZOLaB uses Type 2734 to power sound source Type 4292 during building and room acoustic field measurements. It has XLR, jack and BNC input sockets and BNC line and speaker output sockets. A sensitivity selector in 10 dB steps allows the amplifier to adapt to a variety of source signal levels and sound source ratings. Hand-held Analyzer Type 2250’s generator signal can be connected to the amplifier input to provide the pink or white noise used in building acoustics. Type 2734 has a built-in generator providing pink or white noise in the 50- 5000Hz range. It can be controlled from the front panel as well as with the Wireless Remote Control UA-1476. Transmitter UA-1476 has a push key for manual control and a cable connection for automatic control from the Hand-held Analyzer.

» Tapping Machine B&K Type 3207

MEZZOLaB employs Tapping Machine Type 3207 as an impact sound generator for impact sound measurements to national and international standards. Type 3207 uses five hammers each weighing 500g and operating at 2Hz dropping from a height of 40mm, giving an operating frequency of 10 Hz. The hammers are operated via tappets on a single shaft. The shaft is driven by a DC motor via a toothed belt and gearbox. Remote operation is possible with the Wireless Remote Control UA-1476. Three extendable legs support the unit during operation with rubber feet that are height adjustable with supplied gauges. This gives stable and level mounting during operation in accordance with the relevant standards.

» Microflown Technologies USP Probe and 4 Channel Signal Conditioner

USP-mini Probe V2.0 2013 – 10 integrates 1 pressure sensor and 3 orthogonally placed particle velocity sensor. The velocity sensor is based in two tiny platinum wires, which are kept constantly heated to 200 degrees. The motion of the air surrounding them produce a temperature decrease in the first wire, the second wire is then less cooled down by the flow. This temperature difference is proportional to the wires resistance, providing a broad band (0 to at least 10 KHz) and linear signal proportional to the particle velocity. The pressure microphone integrated in the probe is a FG-23329-D65. The combination of both sensors allows the direct measurement of particle velocity and sound pressure, hence sound intensity. The Microflown 4-Channel signal conditioner is a 3 functionality device which allows adapting the signal received from 3 particle velocity and 1 pressure sensor to be acquired and processed. It provides the power supply of the probe in order to make it functional and sensitive. This module provides the stable powering to acquire the data from pressure and/or velocity channel.

» Microflown Technologies Scan&Paint V2.0 2013 - 10

Scan & Paint is an easy and straightforward tool to visualize stationary sound fields in broadband frequency range. It makes possible noise source localization, component noise targeting, flanking sound path analysis, transmission loss measurement of building components, assembly quality control and troubleshooting.

» Microflown Technologies Velo 2A Analyser

Analyser is a measurement (data recording) and post-processing software for single- and/or multichannel measurements. It is capable of real time analysis of inputs, not only from the Microflown sensors, but also standard sound pressure microphones and accelerometers. The channels can be configured from just 1 up to 1024channels, supporting a diverse range of frontends as of Scout422. It provides direct recording and analyzing options, as well as has an extensive export functionality to be able to export time data and correct data.