| 1. |
- Algers, Staffan, et al.
(författare)
-
Valuation of road traffic noise profiles
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009. - 9781615676903 ; , s. 2161-2168
-
Konferensbidrag (refereegranskat)abstract
- Swedish noise values are today based on a study concerning hedonic price values. The valuation of the average noise levels assumes that there is no difference between different noise profiles, i.e. how the noise level varies throughout the day. In order to be able to take appropriate measures towards noise problems, it is important to know to what extent the noise profile matters. The project aims at researching how the noise value depends on the road traffic noise profile. It further aims at studying how values are affected by the type of activity in which the noise disturbance occurs (being out in the garden/try to sleep in the bedroom). Our method is to use stated preference techniques (pair wise choices) to elicit noise profile values. Respondents listen to and evaluate noise profile where we vary the level of background noise, frequency of noise events and the noise level of the events. This paper also discusses possibilities to estimate willingness to pay for changes in different components of noise profiles.
|
|
| 2. |
- Johnsson, Roger, et al.
(författare)
-
Self assessment of speech intelligibility listening to binaural recordings
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 43-51
-
Konferensbidrag (refereegranskat)abstract
- Our ability to focus on a talker in an environment with several talkers is improved by our binaural hearing. The ability to listen to one talker is improved if the talkers are spatially well separated. A common problem with binaural recordings is front-back confusion, which can make it more difficult to focus on the target talker among several talkers. In this study the ability to localize a talker is compared to the ability to follow a talker in situations with several talkers. In the first part the subjects were asked to localize a talker in the horizontal plane listening to binaural recordings. In the second part of the study the subjects were instructed to assess their ability to follow a target male voice in presence of a masker consisting of two voices (male and female).Target and maskers were presented through separate loudspeakers in various positions. The same listening test was also performed with binaural recordings of the test environment using different artificial heads and in-ear recordings of humans. In both parts the binaural recordings were presented to the subjects through loudspeakers using cross-talk cancellation. Correlation between localization performance and self assessed speech intelligibility was analyzed.
|
|
| 3. |
- Ljunggren, Fredrik
(författare)
-
Using elastic layers to improve sound insulation in volume based multi-storey lightweight buildings
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 252-257
-
Konferensbidrag (refereegranskat)abstract
- Lightweight buildings often suffer from poor sound insulation, especially at low frequencies. The volume technique in which sections are being assembled to form a complete building, are well suited for the use of elastic layers in between floors as an action to improve the sound performance.Upon the floor construction's load-bearing beams, one or multiple layers of boards are normally attached. Particle boards and/or plaster boards are installed using screws and/or glue. In the case of using glue solely, there is a potential to improve the sound insulation if glue with elastic properties is used instead of a traditional one which will harden completely.Results from using different kinds of elastic layers between floors as well as different kinds of board glues, all tested on identical constructions, are presented in terms of airborne sound reduction and impact sound pressure level.
|
|
| 4. |
- Löfdahl, Magnus, et al.
(författare)
-
Measurements of variations in binaural transfer functions caused by displacements of sources and receivers
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 4694-4702
-
Konferensbidrag (refereegranskat)abstract
- Noise generated in cars is transmitted through airborne and structure borne transfer paths into the cabin. Changes in the locations of either the source or the receiver will alter the transfer path. Binaural transfer functions of airborne sound were measured in order to determine how changes in locations of either the source or the receiver affect them. The measurements were performed on a car where the binaural transfer functions for various positions of the source and the receiver were measured directly. In addition, examples of automotive sounds were reproduced through a loudspeaker in the source position and recorded with an artificial head in the receiver position. Changes in perceived sound quality caused by displacements of the source and the receiver position was studied through a listening test and compared to the changes in binaural transfer functions. The results show that the binaural transfer functions are affected by small displacements in location for either the source or the receiver. This variability causes changes in sound quality and must be considered in order to draw correct conclusions from transfer function measurements and sound quality analyses based on artificial head recordings.
|
|
| 5. |
- Morgan, Phil, et al.
(författare)
-
The selection of new reference test tyres for use with the CPX method, to be specified in ISO/TS 11819-3
- 2009
-
Ingår i: INTER-NOISE 2009. - : Institute of Noise Control Engineering ( INCE ). - 9781615676903 ; , s. 462-470
-
Konferensbidrag (refereegranskat)abstract
- The draft for ISO standard ISO 11819-2:2000 for CPX tyre/road noise measurements includes specifications for a set of four standard reference test tyres. These commercially available tyres were selected to cover the different mechanisms responsible for the generation of tyre/road noise. Three were chosen to be representative of passenger car tyres and one to be representative of heavy vehicle tyres. Since the draft standard was first written, these tyres have either been superseded or discontinued. It has therefore been necessary for ISO/TC 43/SC 1/WG 33 (Measuring Methods for Comparing Traffic Noise on Different Road Surfaces), the Working Group responsible for the Standard, to define recommendations for an updated set of reference tyres, at the same time considering whether fewer tyres could be used. This paper provides a summary of the recommendations for the new reference tyres and an overview of the review process which formed the basis of the recommendations, presenting specific results from the evaluation of candidate replacements for ISO tyre A.
|
|
| 6. |
- Mosharrof, Mohammad Sazzad, et al.
(författare)
-
Prediction model for the impact sound pressure level of decoupled lightweight floors
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 2038-2046
-
Konferensbidrag (refereegranskat)abstract
- Prediction of impact sound insulation in timber buildings is difficult since the constructions are complex, non isotropic and show large variances. There are earlier publications on precise models of simplified structures and simplified models of complex structures, where so far, none is considered as an acceptable simplified engineering model tool. The goal of our research is to develop methodology for such a simplified engineering tool. The starting focus is to model impact sound in a simple floor model of two plates that are realistically coupled via beams. The floor structure in Nordic countries is mostly decoupled, meaning there is either no structural connection or an elastic connection between the plates and the beams. In this paper, an improved floor model is proposed where as a first step there is no physical connection between the plates and beams, and where each plate is stiffened by separate beams. Hence the construction becomes more realistic as only coupling between the plates via air trapped inside the cavity is taken into account. Next step will be to introduce resilient coupling between the respective beams. The modelling show promising results with reasonable sound insulation improvements.
|
|
| 7. |
- Nykänen, Arne, et al.
(författare)
-
Examination of the variability between artificial head recordings made in different cars of the same brand and model
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 4687-4693
-
Konferensbidrag (refereegranskat)abstract
- Artificial heads are commonly used for the recording of samples intended for sound quality evaluations. When results from listening tests and psychoacoustic analyses shall be compared it is important to be aware of the variability between measurements made under similar conditions. To study this kind of variability, the interior sounds of five passenger cars of the same brand, model and production year were recorded binaurally. The recordings were made using two different artificial heads (Head Acoustics HMS I and HMS III) and a binaural microphone headset (Head Acoustics BHM). The recordings were made at constant speed on a test track with controlled surface roughness. Based on the recordings loudness, sharpness, roughness and annoyance were judged in a listening test. The results show how the sound quality can be expected to vary between specimen of cars of the same brand and model. This observed variability was compared to the accuracy of the three different binaural microphones used.
|
|
| 8. |
- Otsuka, T., et al.
(författare)
-
Environmental sound art technology
- 2009
-
Ingår i: INTER-NOISE 2009. - : Curran Associates, Inc.. - 9781615676903 ; , s. 714-725
-
Konferensbidrag (refereegranskat)abstract
- Soundscape is a concept describing our general sound environment. It includes both (desirable) sound and (unwanted) noise; although one of these may be weak or not noticeable in some soundscapes. Environmental sound art is an art form which uses our hearing to make us aware of our soundscape. It is used more and more to enrich our acoustical environment; sometimes to raise the interest of people passing-by and make them listen; sometimes to move the attention from noise to sound, sometimes to counteract a poor and dull environment in a place where many people pass-by, and in some cases just as an expression of art for the enjoyment of the listener. Its importance as a way of improving our acoustical environment is increasing. Sound artists frequently use various technologies to achieve their aims. This paper attempts to describe the subject for noise engineers, to raise their interest in it, and to bridge the gap between the artistic and technological sides of the problem. It is concluded in the paper that environmental sound art is a valuable tool for influencing our soundscape in a desirable way; not the least for improving our acoustical impression of noisy or acoustically poor environments.
|
|
| 9. |
- Sandberg, Ulf
(författare)
-
The composite wheel : an innovation featuring low tire/road noise and low rolling resistance simultaneously
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Ames, IA : Institute of Noise Control Engineering ( INCE ). - 9781615676903 ; , s. 423-434
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Composite Wheel (CW) is an invention by a Swedish engineer which was tested by VTI in a first version in 1989. The CW is a tire/wheel construction with a rubber tread mounted on a belt supported by a self-supporting structure (plate and “spokes”) made of composite materials. This early design was found to give 10 dB lower noise than an “average” conventional tire. However, durability was insufficient. In a recent North-European cooperative project led by VTI, new versions of the CW were developed and tested. The first series of new prototypes failed, partly because spokes in the wheel construction created noise emission at the spoke impact frequencies which dominated the noise emission, partly because of insufficient adhesion strength between spokes and belt. In a second series of prototypes, the spoke-related noise was reduced to acceptable levels and lower noise emissions than for any pneumatic tire were measured. Rolling resistance was extremely low, and vehicle handling was reasonably good for being a prototype. There are still some durability problems although much less than before. It is concluded that the CW has very promising features in terms of low noise emission and rolling resistance. The paper presents the latest results measured for this tire/wheel construction.
|
|
| 10. |
- Öqvist, Rikard, et al.
(författare)
-
Variations in sound insulation in multi-storey lightweight timber constructions
- 2009
-
Ingår i: 38th International Congress and Exposition on Noise Control Engineering 2009. - Red Hook, NY : Curran Associates, Inc.. - 9781615676903 ; , s. 315-323
-
Konferensbidrag (refereegranskat)abstract
- By using industrialized building, pre-installed modules can be delivered to the construction site where they are easily mounted. This method has many advantages compared to on-site manufacturing. In general, the variability of sound insulation is large in lightweight constructions. The reasons behind this variability are not known and therefore the construction is over-dimensioned to make sure the requirements are met. If the causes of this variability can be found and controlled, the production cost will be reduced and the sound quality improved. This is possible, since much of the construction takes place under controlled circumstances. Field measurements of 31 apartments in a four-storey building have been made. Both airborne and impact sound insulation were measured. The apartments on the highest floor achieved significantly better sound insulation. This is an indication that preload is a factor which contributes to high flanking transmission. The structural coupling between modules will therefore be studied in depth. This paper will present the results from the measurements and propose further research.
|
|
