100hz is belong to mid bass, if ur bass have come with "blur", u can try to minus it.

315hz is belong to low mid, always effect ur male vocal sound come with "blur", then u can minus this 315hz.

1.25khz is belong to high mid range frequency, if this frequency have a peak , it will make the sound like the phone talking, then u need to minus it.

3.15khz is belong to high mid range frequency also , when this frequency got peak, u will feel the vocal sing like shout.

8khz is belong high range frequency , always make the vocal sound have a problem when she / he sing "sh, ch, s"

you are welcome

EQ can help u make the sound good, but EQ also can make the sound bad.
For me, EQ tweak adjusting is ok, too many EQ adjust really with effect the sound unnatural.

Try, make a good installation to ur driver, and find a good placement for ur driver, it can less to use EQ tune the sound

good installations and good placement for speaker, then sure will less EQ tuning, cos u have less acoustics problem into ur car.

bad installations or ban placement for speaker, sure got alot of acoutics problem, then u need EQ to help u settle it.

Less EQ tuning and more natural sound.

Nature Sound Design

argee with u.
HU design nice, but for sound quality。。。。。。。lebih kurang with entry level one