Acoustical Simulations and Predictions

Highly specialized software tools licensed to MEZZO Stüdyo aid our designers in the prediction of acoustical quantifiers even in the design phase of ongoing projects. How the proposed design sounds necessitate a way of prediction, modification, and control. The use of simulation-based estimations includes both room acoustics, building acoustics and noise control studies. Apart from below listed commercially available products that the company possesses, MEZZO Stüdyo has also implemented its own in-house estimation tools to provide assistance for efficient and profound acoustical calculations and to speed up design progress.

ODEON Room Acoustics Software (the most recent versions updated annually) is adapted as the prime acoustical simulation software by MEZZO Stüdyo in estimating room acoustical parameters such as reverberation time, early decay time, clarity, definition, lateral fraction, strength, sound pressure level and sound transmission index. From undersized to large scale projects in the field of consultancy ranging from theatres, multipurpose halls, opera houses to offices, public buildings, and subway stations it is crucial for Mezzo Stüdyo to take the necessary preemptive actions at the early design phases both in room acoustics and noise control issues. 

MEZZO Stüdyo consults BASTIAN in sound transmission predictions between rooms within buildings and between indoor and outdoor environments. It is based on part 1 and 3 of the European Standard series EN 12354 and adopted by the majority of the European countries including Turkey as part of their national standards. These calculation procedures form the common basis for the prognosis of sound insulation of buildings. 

Airborne sound insulation of walls, partitions and floor or ceiling assemblies, separating dwelling units from each other or from public areas, should satisfy certain sound transmission class (STC/Rw/DnTw) limits. Floor or ceiling assemblies between dwelling units or between a dwelling unit and a public or service area within the structure shall also have a specific impact insulation class (IIC/LnTw) rating. INSUL aids MEZZO Stüdyo designers to predict airborne sound insulation and structure borne sound isolation characteristics of building elements, and assist accordingly to devise improved project-specific details and material compositions. INSUL also provides STC/Rw information to BASTIAN for tested material compositions, system assemblies or building elements. 

Prediction of sound absorption properties of slatted and perforated absorbers is important as they are frequently used to control the acoustics of rooms. Especially in design phase of sound absorbent materials in aim of achieving specific acoustical characteristics, predictions are highly practical and time saving. In that respect Mezzo Stüdyo team utilizes ZORBA to calculate the acoustic impedance, the normal incidence absorption coefficients and within certain limitations the random incidence absorption coefficients of specific materials and systems.

Modes in small rooms often lead to extended sound decays and uneven sound characteristics both in frequency and time domains. In critical listening spaces, this causes unintended coloration effects that can be detrimental to the sound quality. The problem arises at low frequencies because of the relatively low modal density. The Room Sizer model provides inherent weighting of axial, tangential and oblique modes for a specific room by numerical optimization method and assists MEZZO Stüdyo designers in estimating the best dimensions of a room for minimum coloration effects of modes. 

SONarchitect ISO is a software tool for the estimation of acoustic performance of buildings from the performance of elements (EN 12354). The prediction algorithms according to EN 12354, parts 1,2,3,4 and 6 are implemented. The software allows building acoustic predictions of irregular room shapes and of the entire building. SONarchitect ISO predicts Airborne sound insulation (EN 12354-1), Impact noise (EN 12354-2), Airborne sound insulation against outdoor noise (EN 12354-3), Transmission of indoor sound to the outdoor (EN 12354-4) and Sound absorption in enclosed spaces (EN 12354-6). 

CADNA software is used to predict environmental noise levels due to industrial noise sources, railroad and road traffic with regards to Cnossos. It considers the ISO 9613 standard for modeling noise propagation outdoors. Mezzo Stüdyo mostly applies the software to model the outdoor noise sources related to building services as of generators, chillers, outdoor units of MEP systems to observe their impact on facades, terraces or outdoor circulation zones of multi-use building complexes. Accordingly, noise mitigation measures are developed and tested in series until the desired outdoor or indoor noise criteria is satisfied.

Acoustical Tests and Measurements

MEZZO Lab 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. 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
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
ISO 10534-2:1998 - Acoustics - Determination of sound absorption coefficient and impedance in impedance tubes - Part 2: Transfer-function method
Equipment for measurement of sound insulation in buildings and of building elements and room acoustics parameters are listed as follows

• Power Amplifier (B&K – Type 2734-A)
• Tapping Machine (B&K – Type 3207)
• Omni power Sound Source (B&K – Type 4292 –L)
• Omni power Sound Source Light-weight Tripod (B&K – Type UA 0801)
• Hand-held Analyzer (B&K – Type 2250-A)
• Microphone (B&K –Type 4190 ZC-0032)
• Accelerometer (B&K- Type 4507 B 004)
• Protective Cover for Hand-held Analyzer (B&K – Type UA 1236)
• Large Round Windscreen (B&K – Type UA 0237)
• Hand-held Analyzer AC adaptor (B&K – Type ZG 0426)
• Hand-held Analyzer Holder Tripod (B&K – UA 0801)
• Sound Calibrator (B&K – Type 4231)
• Wireless Remote Control Receiver (B&K – Type UA 1476)
• Wireless Remote Control Transmitter (B&K – Type UA 1476)
• Switchbox AC Adaptor (CINCON Electronics – Model TR60M15 / 62E13)
• Extension Cables (B&K)
• USB Audio Interface (B&K – Type ZE 0948)
• Miscellaneous
    o Type UA 1673
    o Type UA 1654
• Type UA 1317 Microphone Holder

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, characteristic 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 comprise small and large diameter 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 MEZZO Lab.

MEZZO Lab adapts DIRAC by Brüel and Kjaer 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 in room acoustics.

DIRAC enables recording of room impulse responses (RIR) and post-processing RIRs to assess a wide range of room acoustical parameters including Early Decay Time (EDT), Reverberation Times (T10, T20, T30), Strength (G). Center 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 standard, internally or externally generated MLS or sweep signals through a loudspeaker source can be used. Speech measurements can be carried out in compliance with the IEC 6026–16 standard.

Building Acoustics Software BZ-7228 is a complete application package used with Hand-held Analyzer Type 2250, as part of B&K 2250 Based Building Acoustics System, to hold building acoustics measurements including airborne, facade and impact sound insulation.

BZ-7228 is used for measuring source and receiving room level spectra in field measurements. Having built-in pink and white noise generator this software is presents an option 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, ISO16283-3:2016.

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

BZ-7223 allows MEZZO Lab to take real-time measurements in 1/1 (center frequencies from 8 Hz to 16 kHz) and 1/3 (center frequencies from 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. The software enables vibration analysis in narrow bands and helps acoustical designers to diagnose possible sources of problems as well as to check the effectiveness of vibration control and noise abatement.

Type 2250 hand-held instrument platform provides MEZZO Lab 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 Room Acoustics and Building Acoustics Software.

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 in phase operation and impedance that matches the power amplifier.

Type 2734 amplifier is to power sound source Type 4292 during building and room acoustic field measurements. It has XLR, jack and BNC input capability and as well as BNC line and speaker output options. 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 for use in building acoustics tests. Type 2734 has a built-in generator providing pink or white noise in the 50- 5000 Hz 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.

MEZZO Lab employs a standard 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 500 g and operating at 2 Hz dropping from a height of 40 mm, 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.

Based upon its unique MEMS acoustic particle velocity sensor, Microflown Technologies provides highly innovative sensors and measuring systems suitable for sound and vibration testing, including sound localization, acoustic imaging, and many applications. MEZZO Stüdyo uses this tool in high-end acoustical research such as identifying sound energy flows in three-dimensional space, such as monumental historical superstructures.

The system involves USP-mini-Probe V2.0 2013 – 10, which 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 wire’s resistance, providing a broad band (0 to at least 10 kHz) and a linear signal proportional to the particle velocity. The pressure microphone integrated in the probe is  FG-23329-D65. The combination of both sensors allows  direct measurement of sound intensity and acoustical impedance. 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 to make it functional and sensitive. This module provides the stable powering to acquire the data from pressure and/or velocity channels.

Scan & Paint is a tool to visualize stationary sound fields in broadband frequency range. It makes possible noise source localization, competitor analysis and noise benchmarking, component noise targeting, assembly quality control and troubleshooting.

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 1024 channels, supporting a diverse range of front ends 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.