The sound generated by electric propulsion systems differs compared to the prevalent sound generated by combustion engines. By exposing listeners to various sound situations, the manufacturer can start understanding which direction to take to achieve compelling battery electric vehicle trucks from a sound perspective.The main objective of this study is to understand what underlying aspects decide the experience and perception of heavy vehicle–related sounds in the context of electrified propulsion. Using a thematic analysis of data collected at a listening experiment conducted in 2020, factors affecting the perception of novel sounds generated by a first-generation electric truck are investigated. A hypothesis is that the experience of driving or being a passenger in electric trucks will affect the rating and response differently compared to listeners not yet experienced with this sound.

The results show that the combination of individual preference and experience, hearing function, acoustic content, time variation, signal stability, load-dependent feedback, and situation-equivalent sounds affect the outcome. The assessment and rating of quality and acceptance did not differ between battery electric truck experienced listeners and first-time listeners in general. The only driving condition clearly breaking this pattern was the auxiliary brake condition, which, besides being significantly higher rated by novel listeners, also stood out as the highest-rated and most positively commented driving operation overall.

In conclusion, several combined factors affect the assessment of electric truck sounds. Three identified aspects are removing disturbing sounds, making the sound environment smooth and silent, and providing clear functional feedback. Memory of the contextual experience is a key factor when assessing sounds from driving operations. The expected difference between listeners with and without experience with electric truck sounds will be minor unless there is exceptionally high sound quality.

With electric powertrains quickly advancing in the heavy vehicle sector, there is an increasing interest in the industry to find a general practice for evaluating tonal sounds. The challenge to set requirements is complex. Tonal sounds span from extremely annoying to pleasant. Established methods for prediction of tonal magnitude typically estimate individual tonal components without considering interrelations between the tones. In this study, the loudness perception of continuous complex tones with increasing number of harmonics as well as non-harmonic tone components, is assessed using pink noise as reference. Frequencies studied cover 350–11 000 Hz. These frequencies typically occur in electrified trucks, hitting the most sensitive area of the human hearing. The results show a statistically significant positive linear relationship between perceived loudness and increasing number of harmonics, even with decreasing level of amplitude (−6 dB/oct). Significant differences are seen between harmonic and non-harmonic tonal signals, when the second partial is detuned. Increasing the number of tonal components increases the perceived loudness linearly. Non-harmonic complex tonal sounds are assessed less loud than the corresponding harmonic sounds. In case of complex tonal sounds, models of loudness estimation need to take the number of tone components and their frequency ratios into account.

Artificial head recording and subsequent headphone reproduction have become standard procedures in the automotive sound design process. They are also used in other areas of product sound design and architectural sound design. With an artificial head recording a headphone sound reproduction will be true to life if the listener keeps the head still. Ambisonics recordings capture directional information of the recorded sound field. The ambisonics recording can be binaurally rendered by filtering through Head Related Transfer Functions or rendered for surround sound loudspeaker setups. This study compared artificial head recordings with first order ambisonics recordings. Four conditions, artificial head recording with headphone reproduction, ambisonics recording with headphone reproduction, ambisonics recording reproduced with head tracking headphones (VR), and ambisonics recording with 7.1.4 surround sound reproduction, were compared in a listening test. Stimuli were recorded in public spaces (a restaurant and two lecture halls). The reproductions were compared with respect to perceived pleasantness, listening effort, and realism. The results showed small differences between headphone reproduced artificial head recordings and reproductions based on ambisonics recordings. Therefore, the use of ambisonics recordings could be considered for future sound quality studies and sound design work.

As a part of the on-going city move in Malmberget, Gällivare, the inhabitants of Malmberget mining area need not only new housing but also increased communal services. To accommodate this, the municipality is building a new public building called the Multiactivitiy building. The building will house public services such as: library, sports centre, swimming pools and recreational spaces. The central lobby space creates a hub which connects the different parts of the building and serves as a communal meeting place. The proposed building site, and the site of this study, is in the centre of downtown Gällivare. The study focuses on how ambisonics recordings can be used as a part of the site survey in the early stages of the architectural design process. The spatio-sonic qualities of the existing site are integral to the architectural design process, not only as documentation and analysis of the site’s conditions, but as an integrated design parameter (on par with lighting, climatic, contextual, and other site-specific conditions). A Virtual Reality model of the site, auralized with ambisonics recordings, is the main artefactual outcome of this study. Additional documentation of the site survey includes spatio-sonic mapping of the site plan, written (autoethnographic) impressions from the main surveyor, photographs, ambisonics recordings and a summary and analysis of respondents’ answers to questionnaires in combination with soundwalks. The conclusion of the study is that it is feasible to produce simple, virtual, auralized models that can be used as a base for sketching with sound in architecture.

The monitor mixing engineer is a key function in a public music performance when in-ear monitoring (IEM) is utilized. This paper aims to expand our knowledge about monitor mixing in general and IEM mixing in particular by investigating monitor mixing engineers’ reasoning, decisions and actions. Four experienced monitor mixing engineers were interviewed on monitor mixing in general, IEM mixing and hearing health. Among the results are found that the engineers seek to create a fruitful working relationship with the performers. The engineers also describe what creates a functional mix and they show a high awareness of their responsibility for the comfort and well-being of the artist, both in a psychological sense as well as in providing sound levels that are not harmful. 

A sketch is an important tool that architects use to visualize and formulate design decisions.The sketch process is a crucial stage where design iterations and decisions can be made fast, easy and abundant. Sketching facilitates idea spawning, design assessment, modification and communication. 

This exploratory study focuses on qualities with Virtual Reality that can be used for sketching sound in the architectural design process. The study was influenced by Contextual Inquiry Interviews and used trained architects as respondents. The main result of this study is a summary of the pros and cons on how Virtual Reality work today and discusses how to develop a test bed for future research. 

One of the main cons, as of now, is the bulkiness of the equipment and the fact that it is not intended for sketching sound, yet. Computing speeds and acoustic rendering is another issue on the technical side. A possible benefit of using Virtual Reality is that it gives architects the possibility of incorporating sound in the architectural design process, thus making it an integral part of the practice.

The perception of tonal sounds is one of the most important psychoacoustic sensations of NVH sound engineering. Much work has been done in the past to quantify tonal sound events. Previous studies resulted in several metrics for quantifying tonality, such as Prominence Ratio, Tonality DIN 45681 and the recently standardized Psychoacoustic Tonality (ECMA-74). Although these metrics are designed to assess the tonality of a sound, they do not explain how the pleasantness of a sound is affected by tonal events. This article describes an experiment aimed at evaluating the relationship between tonality and pleasantness of electric vehicle interior sound at different speeds with tonal components between 200 Hz and 900 Hz. It also explores how the established metrics for tonality calculation can be used to predict the pleasantness of these sounds. The results of the listening test are analyzed and compared with the calculated tonality values of the various metrics. The detectability of the tones was also analyzed and could be linked to the pleasantness observations. Furthermore, a hierarchical cluster analysis was performed to further examine the subjective results. Two main groups were categorized from this analysis where one cluster had higher detectability.

In building and infrastructure projects sound design and requirement specification are often complicated by difficulties in understanding how the planned built environment will sound. Information about sounds is almost exclusively provided as sound pressure levels and sound reduction indices. It is difficult to understand how an environment will be perceived solely based on such data. VR models with sound give an experience much easier to comprehend. In this study, VR models were developed based on first order Ambisonics recordings. Such recordings provide spatial information and can be real time rendered based on the listener’s orientation. However, the recordings must be made in discrete points and therefore a model for cross-fading and mixing was developed. Recordings of road and railway sounds were made in a two dimensional grid and mixed and crossfaded based on the position of the listener. The sound levels were adjusted to match calculated levels from noise planning models. The spatial density of the grid of recordings, the cross-fading function, and the mix of recordings were varied and the realism of the models was assessed in listening tests. The results give guidance on how Ambisonics recordings could be mixed in order to achieve realistic sound in VR.

Computer game technology was used for rapid prototyping of a sound based interface encouraging truck drivers to drive energy efficiently. The design process was inspired by user-centred agile methods. Interior sounds were made interactive by actively controlling them based on speed, engine speed, torque and acceleration. User feedback was collected at an early stage through contextual enquiry sessions during simulated driving. Based on the feedback the sounds were adjusted and effects on driver behaviour were measured in a simulator experiment. The effects on driver behaviour were small and not statistically significant (p>.05). However, assessments of preference and informativeness showed statistically significant differences between the design concepts (p<.05). The qualitative part of the study showed that the use of game technology for enabling assessment of interactive sounds in early design phases was useful and allowed for getting users into the loop early on. The framework was found to be suitable for designing interactive sounds, and the data collected provides insight into driver responses to using active noise control as a means for providing information to the driver.

Modern telecommunication services generally use digital speech encoding. Speech encoding degrades the audio with compression and filters to make the data transmission more efficient. To keep conversations and on-line meetings productive and creative it is important that these digital services do not increase the cognitive load. Measuring effects on working memory is one way to estimate cognitive load of the listener. A test with 25 participants was performed to investigate the effects of using the AMR-NB codec, a standardized codec for mobile communication. The memory performance for spoken 12-word lists was measured and AMR-NB encoded speech was compared with unprocessed speech (LPCM 16 bit, 44.1 kHz). A within-subject analysis showed 9% lower recall rate for the AMR-NB coded speech.