I recently bought a new phone. Since I didn't like audio quality I went to Equalizer setting and changed it to Custom:
16k: 10dB
8k: 10dB
4k: 10dB
2k: 0dB
1k: -5dB
500: -10dB
250: -10dB
125: -10dB
63: -10dB
Is this setting okay (I know high frequencies are harmful)? Please note that this is a setting for listening WITHOUT headphones/earphones. With those, normal default equalizer settings are used by my phone.