Head Unit EQ

• 1). Read the user's manual accompanying your head unit. While the functions of EQs are the same no matter what brand of equipment you have, each manufacturer may choose different names for each function. One head unit might have controls labeled "Low", "Mid" and "High." Another brand may use "bass" and "treble." Familiarize yourself with the menus and language of your head unit.
  
  
• 2). Set all EQ levels to their zero or "Flat" settings. Turn off any presets and bass boost functions. Play your favorite CD at a medium volume and allow your ears to adjust to the sound.
  
  
• 3). Adjust the bass setting to taste. Increase or decrease the amount of bass to add fullness to the sound, and listen carefully for any distortion from your speakers. If you have selectable frequencies, try frequencies near 80hz (Hertz).
  
  
• 4). Adjust the treble or high setting to taste. High frequencies add clarity to the sound. Listen for any harshness if increasing this setting. If you have selectable frequencies, try frequencies near 12 khz (Kilohertz).
  
  
• 5). Adjust the mid setting. Mids can effect the overall sound of the music more than any other frequency range. Many stereo systems have preset EQ curves which remove mids. While removing mid range frequencies can make the bass and treble more noticeable, it can also have the effect of reducing the overall volume your system can produce. Listen to many different CDs while adjusting the mids.
  
  

Aftermarket EQ

• 1). Set all sliders and knobs to the zero or flat position.
  
  
• 2). Adjust the bass settings. On an aftermarket EQ, several knobs or sliders correspond to frequencies from low to high, and from left to right. Begin on the left side and work slowly through each frequency's knob or slider, and listen for the most pleasing frequency while listening to familiar music. Look for the frequencies between 60hz and 100hz for best results.
  
  
• 3). Move to the right side of the EQ and adjust the high frequencies to taste. Look for frequencies in the 8khz to 16khz range for the most pleasing highs while listening to music.
  
  
• 4). Adjust the middle frequencies. Look for frequencies in the 800hz to 5khz range and adjust to taste while playing music.
  
  

Amplifier EQ

• 1). Read the user's manual for your aftermarket amplifier and familiarize yourself with the EQ features it offers. If you are amplifying full range speakers, leave the EQ settings flat (zero) and focus on the EQ of your head unit. If you are amplifying sub woofers, find the low pass filter knob. The low pass knob should be labeled as such, or may be signified by a small straight line with a second line sloping downward on the right side.
  
  
• 2). Play familiar music and adjust the low pass filter so that only low frequency sounds such as kick drum and bass guitar are heard through the sub woofer. If the low pass filter has selectable frequencies, try to choose a setting near 80hz for best results, and for the protection of your speakers.
  
  
• 3). Sit in the drivers seat and listen to several different CDs at different volume levels. Make sure your music sounds natural and pleasing at low, medium and loud volumes. Listen for any distortion in your speakers. Go back and make small adjustments to your settings until your stereo sounds the most consistent from song to song.