## 4 Discussion  
Based on real-life applications of the method and by comparing the error of the adjusted and non-adjusted masking thresholds of typical electric powertrain orders, the  
Figure 19: Comparison of adjusted and non-adjusted masking threshold (compact SUV, 23 rd order) (**a**), and delta between the adjusted and the target masking threshold and the delta between the initial masking threshold and the target masking threshold (**b**).  
Figure 20: Comparison of adjusted and non-adjusted masking threshold (compact SUV, 48 th order) (**a**), and delta between the adjusted and the target masking threshold and the delta between the initial masking threshold and the target masking threshold (**b**).  
aim was to gain insight into how the method can take the torque dependency of the masking threshold into account.  
The increased tire noise caused by the tractive force on the tire under high engine torque levels leads to increased masking thresholds in the vehicle interior. The validation results show that the method can effectively reduce the error of the masking threshold compared to those observed without taking the torque dependency of the tire noise into account. Across the entire rpm range, particularly for intermediate engine orders at rotational speeds of the engine above 2000 rpm, the error was reduced to below 2 dB, with further reductions to below 1 dB at higher rotational speeds. This demonstrates the robustness of the method in accounting for torque-dependent influences.  
However, in the early run-up phase, the error of the adjusted masking threshold remains relatively high. Since all examined orders in this low-speed range are influenced by the block harmonic, this issue can be addressed in the future by improving the consideration of effects within the block harmonic. As already shown in Figure 8, the current method underestimates the torque-dependent influence in the low-speed range. In particular, adjustments to the rpm-dependent weighting function of the correction factor could lead to improvements. Additionally, at high torque levels, the measurements can be influenced by single noise events, such as cracking noises in the cabin, which are not covered by the developed method. Especially in the early run-up phase, transient noise events can occur and have an impact on the masking threshold in the low-speed range.  
The evaluations of the crossover SUV that was not part of the method's development show that the method generalizes well across different automobile segments. However, compared to the luxury vehicle, the overall error of the adjusted masking thresholds is slightly higher in the crossover SUV. This can be attributed to the large number of different parameters that also influence the sensitivity of the vehicle interior noise to torque, such as differing transfer paths, insulations, mountings, tires, etc., which cannot all be considered in this method. To reach the goal of a generalized method that can be applied to a variety of automobile segments, the considered parameters to derive the method were limited.  
In conclusion, the proposed method can effectively reduce the error of masking threshold calculations by taking the torque level into consideration, with significant improvements observed across the entire investigated rpm range. However, challenges remain at low rpm due to the assumed influence of the first block harmonic and to better account for transient noise events. Expanding the method to include additional vehicle-specific parameters while maintaining its generalizability will enhance its robustness and applicability to a wider range of automotive segments.