Currently sound is commonly measured in the linear logarithmic decibel system. Measurements are taken from the products sound source to determine the sound pressure level, the difference in pressure between a sound wave and the ambient air pressure. This system is complex because every three decibel increase equates to a doubling of sound intensity or acoustic power therefore the level of declared decibels is often not easily interpreted as to how loud something will be actually be experienced.
Also, sound is context driven and the same sound may be perceived differently in different places, at different times, and often dependent on an individual’s emotional response to that particular sound. Beyond this the tone and frequencies of sound add another layer of analytical complexity in the evaluation process.
This is an acoustic model visualisation of a single source of sound propagating in a room. Reverberation is a significant consideration in respect to the quality of the indoor soundscape. For example, hand dryers can often be very high in decibel level and can be highly distressing to some listeners.
All sounds, except sine waves, are made up of multiple frequencies, which determine the character of the sound. Typically, it's not just the sound level that causes distress but the frequency distribution too, where excessive high frequency content can be unpleasant to listen to.
Quiet Mark leads its definitive acoustic measurement system engaging with global specialist acoustic teams. Quiet Mark conduct assessments of declared technical test data, and acoustic measurement of products in the purpose-built Quiet Mark test laboratory and specialist acoustic lab partners for specific product categories.
Anderson Acoustics is at the forefront of acoustic measurement affiliated with the Institute of Acoustics and Association of Noise Consultants.
Quiet Mark is established with Good Housekeeping Institute in North America and Canada with a long-standing acoustic testing association.
HEAD Acoustics is one of the world’s leading companies in the comprehensive analysis of sound and vibration wherever acoustics and sound quality play a role.
Intertek is a leading Total Quality Assurance provider to industries worldwide providing acoustic testing for Quiet Mark in specialist laboratories.
Our comparative data analysis continuously checks the best acoustic performance in each product category in a repeatable test environment. Because the nature of sound transmission is complex, the decibel level of a product may change considerably depending on the context in which it is functioning. Therefore, a product may register a different decibel (dB) level in another context to the Quiet Mark laboratory or published data from industry test levels. Giving out the definitive dB level of a product may be confusing. In addition two similar functioning products may emit the same decibel level, however one may sound pleasant and the other sound unpleasant and irritating. This will not be reflected in the decibel measurement.
Quiet Mark certification is unique as a consumer/trade champion providing reliable and independent information about the sound a product makes before purchase. This information is also important for the manufacturer who needs to know where their product sits in the market and whether to invest in better sound design.
Acoustic product data is compared like for like in each category triangulating the core performance data of the product with its acoustic performance. From a comprehensive data set of a selection of current comparable market samples for each category, between 10% to 20% of the quietest best performing products are awarded Quiet Mark certification. Each product category is re-evaluated annually to reflect new models coming on to the market.
The Quiet Mark acoustic testing laboratory has been purpose built with hard floors, walls and surfaces to reflect a realistic domestic home, office or washroom environment with tiled surfaces and open plan living space to make sure we test repeatably in the toughest acoustic setting. Small Domestic Appliances (SDAs) and home/office technologies including kettles, food preparation, floor-care, personal grooming and office equipment are tested with a sound meter at the source of the sound output, but without influence from external environmental noise with typical background sound levels falling well below 25dB(A).
Another factor that is considered during the Quiet Mark acoustic assessment is the listener experience of that appliance. Most sound isn’t monotone—it typically comprises many frequencies at varying levels. A product may have a low-noise output, but may also have an annoying element to that sound quality which may mar the consumer experience. This is also taken into consideration in the assessment process.
Quiet Mark’s expert acoustic analysis team independently reviews declared acoustic test and core performance data based on BS EN or ISO standards comparing products in category and subcategory like for like with other products currently on the market, including dishwashers, laundry, refrigeration, extractor hood and home technology.
Between 10% and 20% of the quietest products in each category are eligible for Quiet Mark certification. Each product category is re-evaluated annually to reflect new models coming on to the market to provide the public with latest qualifying models. Quiet Mark has built unique market-wide datasets over many years to monitor progress in acoustic engineering.
Typically air control products often have a low decibel range, however the quality of the sound emitted and the length of time the product is being used in close proximity to the user in sleeping, working, and living environments, means the frequency analysis of these types of products need closer inspection to analyse their sound output through various performance modes. Quiet Mark take the loudest readings of an air control product to determine its eligibility for Quiet Mark certification whilst again core performance is compared like for like as in all other standard assessment procedures. Air control categories include air purifiers, dehumidifiers, humidifiers, cooling and heating fans, extractor fans, air conditioning units and domestic ventilation systems.
Assessing sound absorption or impact noise is measured using BS EN and ISO standards. The independent testing data for these products are validated and assessed by the Quiet Mark expert technical team and Quiet Mark certification awarded to those materials or solutions deemed to function at an optimum level for their specific application area. Quiet Mark’s Acoustic Academy for the Building sector includes assessment of every type of building material organised in a master frame work for every building application area including: Residential, Commercial, Education, Public Spaces, Healthcare, Infrastructure, Governmental, Civic where Quiet Mark certifies: exterior sound sources, sound build up and reverberation control, sound reduction of walls, floors and doors, impact footfall and sound control, sound masking, heating and ventilation systems and interior sound sources, as an indispensable resource platform for responsible acoustic design to further equip architects, specifiers, self-builders, developers, designers and consultants.
Quiet Mark physically field test domestic Garden and DIY outdoor technology measuring acoustic performance at Quiet Mark laboratory HQ outdoor testing areas, comparing like for like in each category. From Quiet Mark’s extensive databases of products in these categories including declared manufacturer data a selection of current comparable market samples for each category, between 10% to 20% of the quietest best performing products are awarded Quiet Mark certification.
Each product category is re-evaluated annually to reflect new models coming on to the market. For Commercial Technology including for example machinery and vehicles, Quiet Mark conduct an evaluation of the manufacturers declared data measurements to perform independent validation.
Quiet Mark have evolved testing over a diverse range of products as part of the overall mission to find noise solutions to every noise problem, we welcome exploring evaluation of new categories which are not already listed here.
To Apply for Quiet Mark certification please contact us at: [email protected]