Ecophon Acoustic Bulletin

Different room acoustic descriptors correspond to different human sound attributes. These attributes can, for ordinary rooms, be described as reverberance, speech clarity, auditory strength and spatial decay. If you want to know more about room acoustic descriptors, press here!
If you want to know which technical room acoustic descriptors Ecophon recommends matching these human attributes, please see below for;

Reverberance
Speech clarity
Auditory strength
Spatial decay

Posted by Carsten Svensson at 6:43 PM | Permalink

The Essex study ran for 5 months during the academic year 2007/8 during which period classrooms were repeatedly modified acoustically. Many objective and subjective measures were obtained and initial findings have been described as ‘very powerful’!

Multiple perspectives are always important when considering the impact of the acoustic environment on a system as complicated as a classroom. The Essex School Study held an open meeting during the National School Environment Week in June 2008. During the meeting attendees, including interested people from education, acoustics, charities, parents’ groups and the government, completed a semantic differential questionnaire devised by Dr Markus Meis.

The Essex study ran for 5 months during the academic year 2007/8 during which period classrooms were repeatedly modified acoustically in a counterbalanced experimental design. The 11 staff and 400 children (including hearing impaired children) were kept blind to the acoustic modifications. Many objective and subjective measures were obtained and initial findings have been described as ‘very powerful’ by a consultant from the National College of School Leadership. For further information please contact David Canning at d.canning@ucl.ac.uk. More information will be provided as it becomes available at www.hear2learn.co.uk.

Subjective evaluation of different classrooms by 24 professionals

Click here to enlarge the picture

MA1 (red) = Gypsum + small amount of wall panels (meets BB93, section 1)
MA2 (green) = 15 mm class A absorber + small amount of wall panels (meets BB93, section 6, hearing impaired)
MA3 (purple) = 40 mm class A absorber + low frequency absorber + Wall panels (meets BATOD requirements)
MA5 (blue) = acoustically untreated

Posted by Carsten Svensson at 4:25 PM | Permalink

Dutch sports teachers (PE teachers) sued their employers for suffering serious hearing impairment because of working in a poor acoustic environment. The schools that employed the PE teachers compensate the teachers financially.

The Dutch Royal Society of Physical Exercise Teachers (KVLO) http://www.kvlo.nl/ supports the teachers in this matter.

On September 10th (2008) an article occurred in the Dutch national press. Some sports teachers (PE teachers) sued their employers for suffering serious hearing impairment because of working in a poor acoustic environment.

The Dutch Royal Society of Physical Exercise Teachers (KVLO) supports the teachers in this matter. At their website you can find intersting material (in Dutch) such as acoustic guidelines

Off course bad acoustics is not a new problem! In 2002 Baukje Zandstra of KVLO published a report about teachers with hearing problems, vocal problems, fatigue and stress.
This was one of the main reasons for a stricter Dutch Standard which was implemented in 2005.

Most of the time multidisciplinary sports accommodations have hard floors, walls and ceilings. This in combination with the large volume causes high noise levels and a lot of reverberation.
When the teacher uses his/her voice to teach, it is very difficult for students to pick up speech. Especially in a noisy environment like a sports hall where the teachers voice needs to cover long distances this becomes very hard. This means the teacher needs to raise his voice in an unnatural way.
Besides that it is unsafe. In emergency situations the teacher should be able to react quickly. This means he or she has to be able to hear what happened and to locate the spot where his/her attention is needed.
In rooms with high, long parallel walls, like sports halls, annoying flutter echoes occur.
In sports halls we often see reverberation times from over 3.0 seconds and sound levels of over 80 dB(A) on a regular basis.

When choosing sound absorbing materials for walls and or ceilings it is very important to use materials which have good absorption also in the lower frequencies. If you don’t take this in account, you will have problems with meeting the standard for the maximum reverberation time per frequency.
Besides that it is very important that the chosen materials are suitable for high mechanical impact.

Posted by Carsten Svensson at 2:07 PM | Permalink

Ill. Logica Call Centre, Bridgend, UK

A lot has been written about working conditions in call centres and other customer contact centres, but actually very little about acoustics. Apart from the fact that they are noisy and that employees tend to suffer from noise exposure similar to that of industry workers.
That is why, the French Stadardization body AFNOR, supported by INRS, a French Institute competent in the area of occupational risk prevention, organizes a full day on the subject. Some of the contributions:
- ergonomical approach
- hearing risks related to call centre work
- acoustic perfomance of call centre facilities: descriptors, workstation treatment vs room acoustic treatment, developments in head set technology and training of workers.

Venue: AFNOR, St Denis
Date: 19th of November, 9.15 - 17.15

Access the invitation

Posted by Marc Janssen at 9:11 AM | Permalink

"The acoustical evaluation of rooms requires several room acoustic descriptors. Reverberation time alone is not enough!" says Erling Nilsson, Acoustics Specialist at Ecophon.

Room Acoustic Comfort™ (RAC™) means that, when performing an evaluation of room acoustics, it is important to take into account different types of rooms and what people do there.
Give priority to the different acoustic properties such as reverberance, speech clarity and sound level, depending on what the room is used

To learn what you can do to achieve Room Acoustic Comfort™, simply look here
To get the information in othere languages than english, go here and choose your country

Posted by Marc Janssen at 4:10 PM | Permalink

Voice is a basic tool for teachers. Chronic voice disorders, very common among teaching staff, cause long term sick leaves or leaving the job for good (for other profession or for disability pension). In Poland, chronic voice disorders as a group of diseases are formally recognized as occupational disease. In 2007, officially confirmed voice disorders cases were the biggest group (24,4%) of all occupational diseases in Poland

According to Nofer Institute of Occupational Medicine in Łódź, 70% of teachers suffer during their career different forms of temporary or permanent voice problems (hoarseness, painful speech difficulties, or even aphonia). For teachers, voice disorder risk is five times bigger than for other “voice-working”professionals like lawyers, priests or singers.

Phoniatrists point out the main risk factors:
- noise and low speech intelligibility in most classrooms force teachers to speak too loud
- too dry and dusty air in the classroom
- air currents
- stress
- lack of voice emission training

Since 80’, chronic voice disorders are on the Polish, official occupational diseases list. The formal name of this illness is “chronic voice disorders due to excessive vocal effort lasting at least 15 years”. This general term contains three different diseases: hard vocal nodule, secondary hypertrophic changes of vocal folds, paresis of adductor and tensor vocal fold muscles with glottis insufficiency and persistent hoarseness. In last few years there is stable number of new, formally confirmed cases: about 800 per year. During 20 years, between 1988 and 2007 there were 40.000 cases – when average number of active teachers in Poland was 550 thousands. The teacher with formally confirmed voice disorder has a right for fully paid sick leave (maximum three sick leaves, a year long each) or for disability pension. In 2000 polish Ministry of Education estimated occupational diseases in education (which are in 98% voice disorders) cost for 25 milions €.
Teachers generally work in rooms (classrooms, lecture theatres, sport halls etc). These rooms should be designed, built and furnished in the way to provide the best possible environment for teacher’s vocal effort. The room acoustic comfort is the key factor.

Posted by Mikołaj Jarosz at 2:01 PM | Permalink

Noise can make it more difficult to cope with pain. A nursing study performed by Barbra Blake Minckley showed that twice the number of patients were administrated pain medication when noise levels were “High” compared with “Low” or “Middle”.

Even quite moderate noise levels can potentially disturb the process of caring for the patient.
She said "If there was a way to facilitate the communication between staff members as well as prevent noise from propagating in the room, it would most likely become a more patient friendly environment".

A number of other studies have already shown the benefits of room acoustic interventions (increased sound absoprtion). Among those we are a decrease of sleep disturbance and a lower number of readmission rates.

The brochure "CARE ABOUT SOUND™" compiles most relevant studies on this topic.

”A study of noise and its relationship to patientdiscomfort in the recovery room" as the study by Barbra Blake Minckley is called was published already in 1968. As we know from the study performed by James West and Ilene Bush sound levels in hospitals have increased with at least 15dB(A) since then.

In her study Ms. Blake Minckley also tried to conclude what types of noise had the biggest impact. By observing the faces of the unconscious patients in the ward, she could see that high noises caused the patients to “grimace” and this mostly happened due to voices and laughter in the ward. Typically this would happen when the team of surgeons brought in the patient and chitchatted and laughter as a way to get rid of the tension after a couple of hours of intensive work in the operating theatre.

More info about the study can be found here
This requires subscription (for free)

Posted by Marc Janssen at 11:52 AM | Permalink