Active headsets have been on the market for years and now it is time for something else to enter the stage. The technology of active noise reduction can for exmple also be used in ventilation systems for reducing ventilation noise. An active control system principally consists of four important components, namely the downstream error microphone, the upstream detection or reference microphone, the digital signal processor (DSP) and a loudspeaker. The upstream reference microphone listen to the primary ventilation noise and sends it to the DSP which makes a phase shift to the signal and sends it to the loudspeaker. The loudspeaker sends out the opposite waveform of the incoming one and reduce the primary ventilation noise.

Active headsets have been on the market for years and now it is time for something else to enter the stage. The technology of active noise reduction can for exmple also be used in ventilation systems for reducing ventilation noise. An active control system principally consists of four important components, namely the downstream error microphone, the upstream detection or reference microphone, the digital signal processor (DSP) and a loudspeaker. The upstream reference microphone listen to the primary ventilation noise and sends it to the DSP which makes a phase shift to the signal and sends it to the loudspeaker. The loudspeaker sends out the opposite waveform of the incoming one and reduce the primary ventilation noise.

The report examines the factors which may be a contributing cause to the problems that are present when ferritic stainless steel are eddy current tested in a warm condition. The work is carried out at Fagersta Stainless AB in Fagersta which manufactures stainless steel wire. In the rolling mill there is an eddy current equipment for detection of surface defects on the wire. The ferritic stainless steels cause a noise when testing and this noise complicates the detection of defects.Because of this, a study was made of how the noise related to factors such as steel grade, temperature, size and velocity. By observing the signal and with the possibilities to change the equipment settings the capability to let a signal filter reduce the noise level were evaluated.

Wind power in Sweden is expanding in response to the government's decision that 49% of Sweden's power should originate from renewable energy sources by the year 2020. Problems with noise and sound emissions related to wind turbines are a constant argument against the wind power expansion and this paper means to examine if vertical axis wind turbines might be a viable alternative to the conventional horizontal design for noise sensitive areas. In order to determine factors like difference in frequency, noise propagation and noise emission level, measurements of both horizontal and vertical axis wind turbines have been completed and the data analyzed with MATLAB. It is shown that there is a difference in how the noise from the two types of turbines propagates due to avariation in the frequency spectra of the emitted sound. It is also shown that vertical axis wind turbines generate a lower sound emission with less intensity inthe lower frequencies..

Sound surrounds us in a great extent, we all have experiences of sound and this phenomena has a great meaning in our lives. High levels of sound might be harmful for your hearing and might also cause related difficulties such as tinnitus and sensitivity to sound. Studies reveal a connection between the attitudes toward high levels of sound and the risk behaviours in these situations. The purpose of this study was to explore the experiences and meaning of sound and whether the attitudes toward sound will reflect in a family consisting parents and adolescents. A family consisting two parents and two adolescents participated each and one of them in an interview in this qualitative study that has been carried out of a phenomenological approach.

In Sweden, exercise takes a great part in people?s lives. Health and a good conditioned body go hand in hand. Many Swedes exercise in groups, with aerobics or a similar form of workout at a training facility. A regular workout lasts for about an hour and is accompanied by music.

Noise is a growing health problem. People are not always aware of the injuries that noise can cause. The media culture of today has a big influence on teenagers. This is caused by portable music players, computers, concerts etc. The schools are having larg classes and that can cause a lot irrelevant speech during lessons.

Noise in schools can have negative effect on the teaching environment and speech perception. The national Child Environmental Health Surveys (BMHE) conducted in 2003 and 2011 studied how 12-year olds experience their sound environment in school. Results showed that the number of pupils that experience annoyance from noise increased from 2003 to 2011.Aim: The aim of this study was to study how 12-year olds perceive their sound environment in school.Methodology and material: A quantitative questionnaire survey was conducted in the sixth grade at two schools. The questionnaire used included questions from BMHE and self-produced questions. Sixtynine students answered the questionnaire.Results: Over 50 % of the respondents experience annoyance from noise in school several times a week.

In this Master's thesis, a direct-conversion receiver front-end has been designed in a 0.18um CMOS technology. Direct-conversion receivers (DCR) have obvious advantages over the heterodyne counterpart. Since the intermediate frequency (IF) is zero, the problem of image is circumvented. As a result, no front-end image reject filter is required and the channel selection requires only a low-pass filter, which makes it easy to integrate directly on chip. However, the DCR also suffers from several drawbacks such as extreme sensitivity to DC offsets, 1/f noise, local oscillator (LO) leakage/radiation, front-end nonlinearity and I/Q mismatch.

There are a lot of different sounds in our sound saturated time. Noise is an unwishable soundand a high sound level can give short- or lingering problems for both children and adults.The purpose was to find out if and in that case why children and the activity at the pre-schoolaffects by a high soundlevel. Another purpose was to examine what the effects would be if thepedagogues set about the work to get a good sound environment at pre-school.The investigation was accomplished in shape of qualitative interwievs where six pedagoguesfrom different pre-schools answered questions about a high soundlevel.All of them have been educated to hearing pilotes.The result of this investigation shows that some pre-schools have a high sound levels but notall of them. In those cases where there is a high soundlevel are there often too many childrenat the same place on the same time. That makes the soundlevel even higher and both childrenand adults are getting tired.By improving the sound environment at the pre-school both children and adults often gets abetter activity.Keywords: high soundlevel, hearingpilot, noise, affects on children..

During pre-slaughter handling of pigs the animals are often subjected to methods that induces stress and are a threat to the wellbeing of the animals, such as mixing of groups, loud noise and transportation. A new law will be implemented in 2006 in Sweden that prohibits mechanical noise exceeding 65 dB in abattoirs. The purpose of the research presented in this paper was to examine the effects of noise and transportation on pig behaviour. The activity and aggressiveness of the pigs were examined with behavioural studies during transportation and during three different Noise levels: 55, 75 and 95 dB. Before the noise treatments took place the groups were mixed and half of them were transported for approximately 2 hours. In the study 432 pigs were used.

Background: Phonemically balanced word lists are used when obtaining speech recognition scores in noise. These lists are designed for adults, but are still used for children. To properly obtain speech recognition scores in noise for children, normative data is needed to show what differences there are to be expected between children of different ages. Purpose: The main purpose is to obtain normative data for children in the ages of 7, 10 and 13 years for speech recognition scores in noise using words and to compare these with each other and with normative data of adults. A further purpose is to examine if there is any practice- or exhaustion effect to be seen when obtaining speech recognition scores in noise for children in the ages of 7, 10 and 13 years.Material: The participants were ten 7-year-olds, ten 10-year-olds and ten 13-year-olds.

This report is written on commission by WSP Acoustics. The report studies the outdoor sound levels on school yards in Stockholm. The questions given by the company to be answered was what are the actual sound levels at diffrent school yards with low traffic noise and how can you construct a facade element that reduces the sound level from the outside and meet the indoor requirements. Mesurements for four hours was done at eight schools set north and south of the city centre. The measurement period included one school break and one lunch break.

The Swedish social insurance agency provides financial support for families and children, but also for people with work injury, illness and at old age. During 2012 they saw the amount of notifications of insurance increasing in Sweden, which is a development that cost our society a great deal of money. With the aim to pursue a sustainable development I have therefore devoted this project to wellness and stress management within preschool.The employees of preschool are often dealing with a lot of stress, due to the big groups of children that causes high noise and sound levels. The high noise and sound levels is a contributor to stress which additionally can damage the health and cause impaired hearing loss. About half of the people around their forties until the age of retirement have difficulties understanding speech in large groups.The purpose of this project has been to investigate the causes of negative stress for my target group, women between 30-60 years old who works in preschool.

Constantly growing demands from the costumers in the Automotive industry forces the subcontractors to seek alternative ways to compete. One parameter of quality is the components tolerance against NVH(Noise, Vibraion & Harshness) aspects. Kongsbergs Automotive has developed a new gear shifter platform (Shift-by-Wire) that is sold to Alfa Romeo and used in of their car models. However, the company is not pleased with the components sound quality, therefore the main purpose of this thesis is to develope a number of concepts that is supposed to enhance these NVH-aspects.To get an understanding of the problem an analysis of the causes of the emitted sound has been done parallell to a product decomposition, function decomposition and a Ishikawa-diagram. Together with these methods has a litterature study been performed to get familiar with the physics of an impact and especially the emittment of noise.