SR-231Q feature:* 2U Dual 31 rows 1/3 octave graphic equalizer* Built-in updated noise reduction circuit, low-noise output* 40Hz low-frequency cut filter* Complementary gain control circuit to make frequency point accurate, tone smooth and mellow.* Balanced XLR and 1/4 TRS input / output* To provide high-precision capacitance-frequency precise point* The independent high-pass filter, low pass filter cut extra frequency in order to reduce the loss of power. Independent gain range switching key is to facilitate the different needs. Due to the building structure, there is different frequencies in the different propagation characteristics, that is closely related to the objective volume and material displays in each venue. Having the different frequencies in the different materials of the reflection and sound absorption,which need the equalizer resulting in the uneven transmission characteristics of the venue, and even produced a result of standing wave feedback and howling.