Heavy-weight Floor Impact Sounds Research Articles

Spatial distribution of heavy-weight floor impact sounds according to the household location in a box-frame concrete building

In this study, factors influencing the heavy-weight floor impact sounds were analyzed in situ while considering 59 households in a residential building with identical plans and floor structures. A formula to calculate the contribution of the Li,Fmax of each frequency band to the LiA,Fmax was suggested and the main frequency range was determined as 95% of the LiA,Fmax. Further, a hierarchical cluster analysis was conducted on the Li,Fmax, derived for the main frequency range for a rubber ball and a tire each. As a result, the similarity between heavy-weight floor impact sounds in households located on the same floor was found to be higher than that between sounds in households located on different floors. This difference may be attributed to the fact that the households on the same floor share the same floor slab.

유한요소해석을 이용한 중량충격원 종류 및 평가지표 별 바닥충격음 예측 정확도 검증

In this study, we determined the reliability of the finite element method in predicting heavy-weight floor impact sounds after comparing the predicted and measured frequency response functions of vibration and acoustic sounds in full-scale houses. The heavy-weight impact source included a bang machine and rubber ball. For both vibration and acoustic modes, the predicted frequency response functions showed a similar amplitude as the measured ones. However, there was a small difference in their peak frequencies owing to the non-linear characteristics of concrete. The heavy-weight impact sound from the bang machine was predicted to have a 1 dB deviation when compared with the experimental results and a 2.1 dB deviation in total sound pressure level. The deviation between the experimental and simulation results for the rubber ball was 1 dB for impact sound and 0.5 dB in total sound pressure level. The maximum deviation at each frequency was 5 dB and 4 dB for the bang machine and rubber ball, respectively. Overall, the results indicate that the numerical analysis is useful for developing optimized structures to control heavy-weight floor impact sound with different impact sources and evaluation indices.

EPS 완충재의 동탄성계수 및 두께에 따른 중량 바닥충격음 레벨 분석

This study investigated the relationship between dynamic stiffness, thickness, and heavy-weight floor-impact sound level for EPS resilient materials with 10 MN/m3 ~ 30 MN/m3 dynamic stiffness and 10 mm ~ 30 mm thickness. As a result, the single-number quantity (SNQ) with a bang machine was 52 dB ~ 57 dB, SNQ with rubber ball at 1.0 m height was 48 dB ~ 52 dB, and SNQ with rubber ball at 0.3 m was 43 dB ~ 48 dB. The relationship between dynamic stiffness and SNQ with bang machine was a negative correlation, and that with a rubber ball was a positive correlation. The floor impact sound level at 63 Hz showed a negative correlation with dynamic stiffness, and those at 125 Hz and 250 Hz showed positive correlations for all impact sources. The thickness of EPS resilient materials was negatively correlated with floor-impact sound level over 125 Hz for all impact sources. In addition, a design method of EPS resilient materials is discussed using a contour map of floor-impact sound level in terms of thickness and dynamic stiffness.

Effect of the static compressive load on vibration propagation in multistory buildings and resulting heavyweight floor impact sounds.

Experiments were performed to identify the mechanism of heavyweight floor impact sound transmission through floors in a high-rise apartment building. Vibration and sound levels on each floor of the multistory building were measured. The vibration generated at a given floor was transferred to multiple adjacent floors with decreasing amplitudes proportional to the distance from the excited floor. This vibration transfer introduced significant sound transmissions. The structural static load varied depending on the floor location due to differences in the weight of the structure above the floor, especially for wall construction buildings. The static load at the wall of the bottom floor was the largest among the different floors. The influence of this static load on the impact sound generation was investigated through tests in the actual building and the scale model, respectively. The results were numerically analyzed using the spectral element method. With the increasing static load, the resonance frequencies of the floor increased due to the change in the vibration modes of the structure. The modulated sound generation from the floor vibrations transmitted to multiple layers with larger magnitudes due to this static load.

Classification of heavy-weight floor impact sounds in multi-dwelling houses using an equal-appearing interval scale

Classifications of heavy-weight floor impact sounds based on subjective responses were suggested by conducting two experiments. First, statements describing perceptual acoustic qualities related to floor impact sounds in residential buildings were collected and assessed with respect to the degree of annoyance levels. Equal-appearing interval scaling for indicating level of annoyance caused by floor impact sounds was then created using these statements. As a next step, heavy-weight floor impact sounds with different LA,Fmax and temporal decay rates (DRs) were evaluated in terms of annoyance using both the Likert scale and the equal-interval statement scale in laboratory conditions. Five categories for heavy-weight floor impact sounds were suggested based on the annoyance responses. The extent of acoustic comfort in each class was clearly captured by the statements related to the range of LA,Fmax for each class. Effects of DR and noise sensitivity on the classifications were significant. Differences between the class criteria for impact sounds with DR 60 dB/s and 30 dB/s were approximately 5 dBA. In addition, significant differences were found between the high and low noise sensitivity classification groups for impact sounds in the 50–60 dBA range.

Investigation of the effects of different types of interlayers on floor impact sound insulation in box-frame reinforced concrete structures

In the present study, the effects of resilient isolators and viscoelastic damping materials on reducing heavyweight floor impact sounds from reinforced concrete structures were investigated using FEM simulations and in situ measurements. At first, the dynamic properties of the materials were measured using a beam transfer function method to include the properties in an FEM simulation. As a result, the damping materials provided a higher loss factor and dynamic elastic modulus than the resilient isolators. Subsequently, FEM simulations and in situ measurements were conducted to investigate the effects of the interlayers on the characteristics of floor impact sounds and vibrations. The results indicated that the impact vibration acceleration level and floor impact sounds at low frequencies were significantly decreased owing to the installation of damping materials, whereas the impact sound pressure levels at low frequencies were increased as a result of the use of resilient isolators.

Effect of temporal decay on perception of heavy-weight floor impact sounds

This study investigates the effect of temporal decay on perception of heavy-weight floor impact sounds through auditory experiments. Heavy-weight impact sounds were recorded in apartment buildings with a box-framed type reinforced concrete structure using a rubber ball. Temporal decay was quantified by using the decay rate (DR), defined as the sound pressure level (SPL) decrease per second [dB/s], and the distribution of DR for heavy-weight impact sounds was calculated. An auditory experiment was conducted in order to examine the just noticeable difference (JND) of DR, which was determined by the criteria of 75% correct answers by subjects. It was found that the JND of DR is around 11 dB/s. Based on the distribution and JND of DR, another experiment was conducted to investigate the effect of DR on annoyance perception of heavy-weight floor impact sounds in relation to the level differences. The results indicate that SPL and DR significantly influence annoyance perception; the scale value of annoyance increases with decreasing DR and increasing SPL. It was also found that the degree of satisfaction with regards to impact sounds can be improved by increasing DR, by controlling the sound field of the receiving room.

Effect of Perforated Ceilings on the Floor Impact Noise in Multi-Storied Residential Buildings

In this study the effect of a perforated ceiling on the floor impact noise was investigated. Although a ceiling with an air cavity is effective in the reduction of noise, the level of heavy-weight floor impact sounds might also be increased. In order to determine whether this is the case, various ceilings were constructed with differing levels of perforation, and the sound pressure level due to impact noise was measured. We show that a ceiling without perforation led to an increase in the level of heavy-weight floor impact sound of around 5 dB, whereas a perforation ratio greater than 0.8% did not increase this level. Based on these measurements, commercial perforated ceilings that are applicable to actual residential buildings were designed, and the reduction of floor impact noise was verified.

벽식구조 바닥판의 중량충격음 특성 분석을 위한 축소모형의 활용

This study investigated the characteristics of heavy-weight floor impact sounds of box-frame type structure using 1:10 scale model. Ten types of floor structures(bare slabs and floating floors) were evaluated in terms of dynamic stiffness and loss factor. Floor vibrations and radiated sounds generated by simulated impact source were also measured. The results showed that the bakelite was appropriate for simulating concrete slab in the 1:10 scale model, and surface velocity and sound pressure level of concrete slab measured from the scale model showed similar tendencies with the results from in-situ in frequency domain. It was also found that dynamic behaviors of layered floor structures in the 1:10 scale model were similar to those in a real scale. Therefore, the use of 1:10 scale model would be useful for evaluating the heavy-weight floor impact sound insulation of layered floor structures when the frequency-dependent dynamic properties of each material are known.

A Study on the Method of Measurement of Heavy-Weight Floor Impact Sound Considering the Room Mode in Low Frequency Ranges

Most of receiving rooms for the measurement of floor impact sound have rectangular shapes with couple of meters of dimension, with reflective finishing, no furniture and no curtains. Modal overlaps in those conditions are the major reason for the low reproducibility, and as a matter of course, low credibility in measurement. Especially the standard sound source that is currently being used for measurement of heavy-weight floor impact sounds, would cause many social problems due to the excessive low-frequency energy created, within a range from 63 to 125 Hz, and is difficult to evaluate and measure. To solve this problem, space-time average SPL’s through combinations of rotating microphones was suggested in the preceding research. In this study, measurement method using rotating machine and fixed microphones were compared and analysed by the field measurement. The measurement method using rotating machine has good consistencies with average SPL of entire receiving room. This method is expected to reduce the measurement time and measurement deviation as well as to support building regulation/standard development in Korea for Korean apartment buildings.

Subjective ratings of heavy-weight floor impact sounds in wood frame construction

Subjective ratings of heavy-weight floor impact sounds in wood frame construction

Psychoacoustical Characteristics of Impact Ball Sounds on Concrete Floors

Measurements of impact sounds generated by an impact ball (heavy/soft impact source) were conducted in apartment buildings with box-frame type reinforced concrete structures. Variations in frequency characteristics were found in the impact ball sounds and these were classified into three frequency groups. An auditory experiment was carried out to investigate the relationship between various level indices and subjective responses to floor impact sounds. It was found that sound quality ratings (LL z and N max ) as well as instrumental metrics (L Aeq , L Amax and L m,1/1(63―500) ) showed good correlation with impact sound annoyance. Among them, L Amax was suggested as a practical descriptor of the auditory sensation of impact ball sounds on the basis of measurement and calculation procedures. Additional auditory experiments were conducted to characterize the classified impact sound groups and to evaluate the annoyance of impact ball sounds through paired comparison and semantic differential tests. The results show that the impact ball sound with a dominant sound pressure level at 250 Hz was most annoying. Sound Quality (SQ) metrics were used to explain the annoyance level of heavy-weight floor impact sounds. The annoyance obtained from the paired comparison test correlated well with loudness and fluctuation strength. In the semantic differential test, it was found that the adjectives describing loudness had a dominant effect on the subjects' annoyance levels.

Subjective evaluation of heavy-weight floor impact sounds in relation to spatial characteristics

This study investigated the effect of a spatial factor, the magnitude of interaural cross-correlation (IACC) function, on subjective responses to heavy-weight floor impact sounds. Heavy-weight impact sounds were generated by a heavy/soft impact source (impact ball) in real apartments, so that impact sound pressure levels (SPLs) (L(Amax)) and IACC could be analyzed. Just noticeable differences (JNDs) of impact SPL and IACC were investigated through the use of impact ball sounds. JNDs were determined by the criteria of 75% correct answers by participants, and it was found that JNDs of impact SPL and IACC were around 1.5 dB and 0.12-0.13, respectively. In addition, the annoyance caused by an impact ball was evaluated by changes in these two parameters. The results show that annoyance increased with increasing impact SPL and with decreasing IACC; the contributions of the two parameters to the scale value of annoyance were 79.3% and 20.4%, respectively. This indicates that the effects of IACC should be considered for the evaluation of annoyance, and the subjective response to impact ball sounds can be improved by controlling IACC, as well as impact SPL.

Annoyance caused by heavyweight floor impact sounds in relation to the autocorrelation function and sound quality metrics

This study investigated objective and subjective evaluations of heavyweight floor impact sounds. The autocorrelation function (ACF) parameters and sound quality (SQ) metrics were used to explain the annoyance of heavyweight floor impact sounds. Sounds were generated by a bang machine and an impact ball and were measured in various rooms in apartments with different sound insulation treatments. Annoyance caused by the heavyweight floor impact sound was evaluated using the paired comparison method, with a wide range of objective measures. The effects of the objective measures on annoyance were examined by multiple-regression analysis. The relationship between annoyance and ACF parameters showed the following to be important for evaluating annoyance: sound energy Φ(0), variances of Φ(0) and the maximum ACF amplitude φ 1. In terms of SQ metrics, the important factors for evaluating annoyance were loudness and fluctuation strength. The results showed that floors with viscoelastic damping material reduced Φ(0) or loudness. Viscoelastic damping material also reduced φ 1, which is related to the dominance of the resonance frequency of the floor slab structure and its harmonics. Reduction of the floor impact level at the resonance frequency by viscoelastic damping material resulted in high sharpness.

The development of a numerical analysis method for structure borne sound of building floor slabs, and its application to the evaluation of heavy weight floor impact sounds.

In order to construct an evaluation method for structure-borne sound in building floor slabs, the dynamical analysis method for floor slab vibration in audio-frequency ranges and the numerical calculation method for sound radiation produced from slabs have already been developed. In the present paper, the heavy weight floor impact sound is numerically calculated by generalizing these developed methods, and the effectivity of this simulation method is shown. The vibrational characteristics of the diverse floor slabs and the stiffening effects of beams in particular are also clarified using this method