# Method for Resonant Frequency Attenuation in Dynamic Audio Equalizer
## 2 Materials and Methods
### Filter Bank and Signal Filtering
In percussion instruments, the plug-in produces a higher attenuation of \(-0.5\) dB from 31.25 Hz to 250 Hz, while Soothe2 and RESO generate attenuation of less than \(-0.5\) dB, as illustrated in the Figure 14. The low frequencies present in percussion instruments are of significant importance, as these instruments encompass the entire auditory spectrum and possess a high low-frequency content. All three plug-ins exhibit attenuation exceeding \(-0.1\) dB at frequencies of 500 Hz, 4 kHz, and 8 kHz. However, it should be noted that the proposed plug-in generates \(-3.5\) dB more than commercial plug-ins at the 8 kHz frequency. A total of 65% of respondents indicated that attenuation at low frequencies occurs at the resonant frequencies. Similarly, 67.5% of respondents agreed that attenuation of high frequencies occurs at the resonances. These results indicate that attenuation across the spectrum occurs at the resonances of the percussion instruments. In the guitar group, the plug-ins match attenuation values greater than \(-0.1\) dB from 500 Hz to 8 kHz. With Soothe2, attenuation values match from 125 Hz to 8 kHz. The plug-in of the present work matches RESO from 500 Hz to 16 kHz with attenuation values up to \(-2.6\) dB, as shown in Figure 15. A guitar has spectral content from 82 Hz to 15 kHz, which coincides with the region that the present work attenuates. In the annotators' agreement, 65% of people agreed that the attenuation at high frequencies was above the resonant frequencies. The high frequencies are important since guitars have high harmonic content in this region. In the wind and other instrument groups, despite the proposed plug-in having higher attenuation than the commercial plug-ins in the annotator agreement, there is a discrepancy. The three plug-ins in the two groups matched from 500 Hz to 4 kHz with similar attenuation curves, although the proposed plug-in generates higher attenuation. Wind instruments have different ranges depending on each instrument. Some instruments have mid/high frequency content, while others have mid/low frequency content. As shown in Figure 16  
Figure 13: Octave band attenuation curves for the three plug-ins in the voice group. A similar phenomenon occurs with the group of other instruments. Each instrument has a distinct frequency range. Each instrument is situated within a specific range, and for the listener, it can be challenging to perceive the ranges. This is evident in the results of the inter-annotator agreement, as 53.75% of respondents indicated that attenuation occurred for the resonances in low frequencies, while 56.25% of respondents believed that the attenuation of high frequencies occurred at the resonant frequencies. The highest attenuation value generated by the plug-in in this group is \(-2.8\) dB, as illustrated in Figure 17. There is a higher degree of correlation with the Soothe2 plug-in in eight bands, which are at 31.25 Hz and from 125 Hz up to 8 kHz. Figure 16: Octave band attenuation curves for the three plug-ins in the wind instruments group. Figure 17: Octave band attenuation curves for the three plug-ins in the group of other instruments. This analysis reveals that the design of the developed work is analogous to that of Soothe2, as evidenced by the concurrence of attenuation curves in frequency zones and the degree of attenuation. While the developed plug-in exhibits a greater degree of attenuation in specific frequency sections, the attenuation levels across all bands are comparable. This is attributed to the operational principles of the developed plug-in, which differ from those of RESO.