Equalization

Selectively boosting or cutting bands of frequencies to improve the performance of a sound reinforcement system. These frequency bands will differ from system to system based on many variables, including room acoustics, microphone placement/design, loudspeaker location/design, even air temperature. Approach equalization gently and slowly! After every adjustment, listen carefully to the resulting sound. The goal is to improve sound quality as well as increase the gain before feedback. Selectively boosting or cutting bands of frequencies to improve the performance of a sound reinforcement system. Boosting the low frequencies from 100 to 250Hz makes a vocal bloomy or chesty. When the system is loud enough and/or clear enough, stop equalizing! Also, stop equalizing and examine the complete sound reinforcement system in detail whenever the equalization causes a degradation in the rolling off the low frequencies and accentuating the range from 1 to 5KHz, the intelligibility and clarity can be improved When the system is loud enough and/or clear enough, stop equalizing! Also, stop equalizing and examine the complete sound reinforcement system in detail whenever the equalization causes a degradation in the rolling off the low frequencies and accentuating the range from 1 to 5KHz, the intelligibility and clarity can be improved.
Part of getting the sound you want is knowing where an instrument lies in the frequency spectrum and part of it is just plain experimentation.

Approach equalization gently and slowly! After every adjustment, listen carefully to the resulting sound Here are some of the effect EQ can have in regards to intelligibility. Boosting the low frequencies from 100 to 250Hz makes a vocal bloomy or chesty. When the system is loud enough and/or clear enough, stop equalizing! Also, stop equalizing and examine the complete sound reinforcement system in detail whenever the equalization causes a degradation in the rolling off the low frequencies and accentuating the range from 1 to 5KHz, the intelligibility and clarity can be improved. A cut in the 150 to 500Hz area will make it boxy, hollow, or tube like. Dips around 500 to 1Khz produce hardness, while peaks about 1 and 3Khz produce a hard metallic nasal quality. Dips around 2 to 5KHz reduce intelligibility and make vocals woolly and lifeless. Peaks in the 4 to 10KHz produce sibilance and a gritty quality.

Ideally, you should record in a studio with a sound engineer. Many people say you need to 'have an ear' for recording and this is true to a degree but a sound engineer has been schooled and trained to detect varying frequencies of sound. Dips around 500 to 1Khz produce hardness, while peaks about 1 and 3Khz produce a hard metallic nasal quality. Dips around 2 to 5KHz reduce intelligibility and make vocals woolly and lifeless. Peaks in the 4 to 10KHz produce sibilance and a gritty quality.
if you can afford it, go to a studio with an experienced and knowledgeable sound engineer.

What is bothering you if you can’t hear the guitar for example. Find what’s covering the. guitar. See if you can get away with turning something down first before you move something up. Usually in the end, you’ll be less likely to paint yourself into a corner of always trying to turn everything up louder than everything else and consequently running out of headroom and making the overall mix too loud for the audience and everything else goes along with that. Before you turn something up think of what you can turn down to make it sound better."

That's pretty accurate and helps explain their usefulness and importance. Simply put, equalizers allow you to change the tonal balance of whatever you are controlling Thus equalization effects the tone because it changes the level relationship of the fundamental and harmonic frequencies. We will get an increase in strength of the signal (or the signal component) that has lower frequencies (usually any component below about 500 Hz). You may have heard it said that equalizers are nothing more than glorified tone controls.

If someone has a deep, booming voice you may find yourself cutting the bass and boosting the mids and highs. A female vocalist may have a very light, "airy" voice and may need some help (boost) in the low and mid areas. add some low end to a female vocal, or add some "edge" to a male vocalist with a treble boost.
Simply put, equalizers allow you to change the tonal balance of whatever you are controlling Thus equalization effects the tone because it changes the level relationship of the fundamental and harmonic frequencies

Boosting harmonics is one of the first techniques an engineer learns to increase clarity and distinction on instruments. This is a very valid method of equalizing. Some of the suggested equalizer settings from equalization frequency chart used these techniques:

If an instrument sounds "thin" or "small" one can carefully boost fundamental frequencies to correct this. The microphone could have been poorly placed and/or the harmonics over-boosted with EQ. Another application for boosting fundamental frequencies would be to do so when an instrument was playing by itself .

Frequency ranges and effect of sound quality