Classical psychoacoustics deals with the subjective perception of sounds and their quantitative description. We are your experts when it comes to the acoustic quality of products and environments. Our specialists analyze how sounds are perceived and develop solutions that improve acoustic comfort and user satisfaction.

The following parameters help analyze and evaluate sounds not only from a physical perspective but also in terms of human perception:

• Instationary Loudness: The subjective impression of a sound is largely influenced by its loudness. Loudness is measured in sones, where a doubling of the value corresponds to a doubling of perceived loudness.
• Roughness: If a sound exhibits amplitude modulations with modulation frequencies between 30 Hz and 70 Hz, it evokes a perception of roughness — for example, as heard in a “rolling R”.
• Fluctuation Strength: The human ear is particularly sensitive to slow amplitude or frequency fluctuations (e.g., human speech typically has a modulation frequency of 4 Hz). Warning tones are therefore often modulated at 4 Hz. This parameter allows any sound to be analyzed for its disturbance potential.
• Sharpness: Sharpness describes the spectral composition of a sound. High frequencies lead to a sharper perception of sound. Conversely, boosting low frequencies can reduce sharpness.
• Tonality (DIN 45681 / ECMA-74 Standard): If tonal components are present in a sound, it is often perceived as annoying. Tonality is especially important when evaluating noise emissions from large industrial facilities. It is used to calculate the so-called tonal penalty for determining the assessment level.
• Listening Tests: Computer-assisted listening tests (e.g., A-B comparisons) enable targeted questioning of test subjects regarding the perceived character of sounds. The results are crucial for the further development of products, such as household appliances.

Modern psychoacoustics expands classical approaches by incorporating practical methods for evaluating and designing sounds—especially in technical environments such as vehicle acoustics:

• Engine Roughness Considering RPM: This method calculates the perceived roughness of combustion engine sounds in a hearing-appropriate way. The engine speed controls the filters used, allowing full capture of amplitude modulations. In combination with an Active Sound Design Tool, a desired engine roughness can be configured within the vehicle interior.
• Prominence Ratio, Tone-to-Noise Ratio: These parameters offer a more generalizable assessment of tonality in sounds.
• Sound Quality Index: Results from listening tests are correlated with psychoacoustic metrics and expressed as a formula. This enables the prediction and evaluation of sound quality based on simple sound pressure measurements—without the need for time-consuming listening tests.

• Correlation of objective measurements and subjective auditory impressions: A calculation formula is developed here to predict the acoustic quality of a product sound.
• Listening tests with statistical evaluation for creating a Sound Quality Index: Listening tests form the basis for developing a Sound Quality Index. Depending on the task, various test scenarios can be used, such as A-B pair comparisons, absolute magnitude estimation, ranking arrangements, or comparisons with an anchor sound.
• Evaluation of sound quality: The sound quality can be assessed using different scales depending on the task—absolute, relative, or percentage-based.
• Modification and acoustic validation on the product: This aims to improve sound design, taking into account constraints such as weight, cost, and space requirements.
• Generation of a brand sound for a product: A product’s sound often consists of multiple components whose quality must be consistently maintained through monitoring in the production process to ensure that a specific desired sound character is accurately reproducible.

• Assessment of annoyance for infrastructure planning: Especially in the design of noise protection measures for traffic noise (road/rail), subjective evaluations of their effectiveness are an important tool.
• Assessment of annoyance caused by vehicle defects or manipulations: Defects in rail vehicles, such as flat spots, or manipulated exhaust systems in passenger cars or motorcycles often lead to particularly high noise exposure for residents. Through listening tests, the level of disturbance can be quantified.