## 3 Simulation and Experimental Results  
The horn sound utilized in passenger vehicles typically comprises two variants: the thick horn sound (300-400 Hz) and the thin horn sound (400-500 Hz). These are associated with two types of horns: The Disc Horn and the Snail Horn. Disc Horns emit sound in the frequency range of Thick 300-320 Hz and Thin 400-420 Hz, while Snail Horns produce sound in the Thick 380-420 Hz and Thin 480-520 Hz range. Given that Digital Sounds are artificially constructed rather than derived from a natural source and possess an artificial structure, maintaining clarity at low frequencies presents a challenge. Therefore, the product design was inspired by the Snail Horn structure, and the sound structure was devised to mimic this mechanical design. In traditional horn setups, low and high sounds are emitted by two distinct horns. Hence, prominent digital sound arranging techniques were employed to replicate this arrangement within a Digital Mono channel sound. As shown in Figure 8, horn sounds were generated as two distinct sounds through the Sound Control Unit program. These sounds are tailored to be 400 Hz for the Low Tone Horn and 500 Hz for the High Tone Horn. In typical horn setups, high and low sounds are emitted by separate horns. Therefore, advanced digital sound arranging techniques were employed to replicate this arrangement within a Digital Mono channel sound. Horn sounds are generated as two distinct sounds using the SEGER Sound Control Unit program. Specifically, the sounds are tuned to be 400 Hz for the Low Tone Horn and 500 Hz for the High Tone Horn. The results are shown in Figure 10a,b. Figure 9: The AVAS Sound Flash Unit interface. Figure 10: The stage of producing sounds for the Sound Unit through the program: (**a**) creation of 400 Hz horn sound; (**b**) creation of 500 Hz horn sound. To mitigate interference during sound production, harmonics at specific frequencies (such as 1500 Hz and 2000 Hz) that coincide with or might clash with the harmonics of 400 Hz and 500 Hz have been attenuated. Given the preference for the deep sound to be predominant in the created sound, the attenuation process was primarily focused on the low-frequency components. As depicted in Figure 11, when two audio files are combined and transmitted in a single channel without any editing, the resulting signal may exhibit interference at various frequencies. Moreover, the signal in the _.wav_ file may exceed saturation in certain regions, leading to disruption in the system. To mitigate these issues, a technique called \"Channel Mixing\" in digital arrangement methods was employed. Additionally, the room opening technique was utilized to impart a stereo effect to the sound within the mono channel. By segregating the sound into two distinct tones--namely, a low-frequency tone and a high-frequency tone--based on their fundamental frequency values (\(thick\_freq,thin\_freq\)), it becomes feasible to edit the two sounds in separate channels using the Downmixing method [23]. Subsequently, these edited sounds can be merged into a single channel, as illustrated in Figures 12 and 13. Figure 11: The 400–500 Merge signal, which is created by combining two signals without editing and Downmixing. This merge signal has undergone various mixing processes, including the Downmixing process. Figure 12: Block diagram of the Downmixing Method [23]. In Figure 14a, first of all, adjustments were made in the frequency plane with the help of an EQ Graphic, and notch filters at a rate of 48 dB/oct were applied to the inter-harmonic regions. The aim here is to increase the dynamism of the sound by making the areas that are desired to be heard more distinct, as shown in Figure 14b. Figure 14: (**a**) Notch filter applications; (**b**) simulated result of the notch filter application. Figure 13: Performing Downmixing editing on the audio file using Vectorscope.