Car Audio Systems

Car Audio Install: FAIL

What you need to know! Speakers Subwoofers Tweeters Amplifiers Crossovers Head Units / Receivers Installation

Speakers An audio AC signal (frequency) is sent to the speaker from the head unit The electromagnet coil receives this signal and causes a paper cone to vibrate back and forth at the frequency received This creates sound waves that the human ear can hear and recognize as music

Frequency Frequency is measured in Hertz (Hz) and represent how many times per second a speaker moves back and forth (one oscillation) Humans can only hear frequencies within 20 Hz to 20,000 Hz

What does a certain frequency sound like?

Speaker Range All speakers are designed to vibrate at certain audio frequencies Subwoofers range from 20 to 200 Hz Woofers range from 40 to 1000Hz Mid-range speakers (Mids) range from 300 to 5000 Hz Tweeters (Tweets) range from 2000 to 20,000 Hz

What happens when you play frequencies outside of the range?

Subwoofers Usually 8” to 20” in diameter Supply low base sounds (deep barks like dogs..Woof!) For proper operation and sound quality, you need to buy or make a properly designed enclosure The enclosure or box needs to have the correct air volume to ensure proper movement of the subwoofer

Subwoofer WHHAAAA?

Enclosures: Ported or Sealed? Sealed enclosures have a crisper more realistic sound and bass frequencies sound better Sealed speakers create a vacuum when they are pushed out which helps pull back the speaker for the return motion Ported enclosures are louder due to extra sound waves coming from the inside of the box; however, the sound is distorted/muddied due to the time it takes for the sound wave to exit the port (usually one wavelength behind)

Sealed Enclosures

Ported Enclosures

Tweeters Small speakers that have an output of 2000Hz to 20,000 Hz Creates high pitch sounds like a bird (tweet!) Usually quite small (1-2” in diameter) Small size allows for custom placement in car

Amplifiers Amplifiers are an electronic device that increases the power of a signal Uses power from a power supply and controls the output by matching the input signal but at a higher amplitude (greater volume)

Tech Tips Always go with trusted manufactures so you can trust their ratings Always match amplifier Root Mean Square (RMS) rating with the speakers that are running off of it (amount of power that can be used continuously without damage) Never go off of Peak or Maximum power Never mount amplifiers to subwoofer enclosures Plan for separate amplifiers for subs and speakers

Amplifier Terminology Gain = the increase from the input signal and the output signal Bandwidth = the width of the useful frequency range (is the amp good for low frequency/subs or higher frequency/speakers) Filter = adjustable switch to prevent unwanted frequencies from being amplified

Crossovers A crossover is an electronic filter that prevents certain frequencies from passing on to the amplifier or speaker A high-pass crossover only allows high frequencies to “pass” A low-pass crossover only allows low frequencies to “pass”

Active or Passive There are two basic kinds of crossovers: active and passive Passive crossovers don’t need power to filter the signal as desired Active crossovers require power and ground connections, but give you much more flexibility and fine-tuning control over your music.

Head Units Sometimes referred to as a “deck” Provides a unified piece of hardware that interfaces with all of the components in the sound system Contains small amplifier (usually around 200W) Most have detachable face plates for anti-theft Come in single and double DIN sizes (Deutsches Institut für Normun = German ISO standardized size) Newer models have Bluetooth, GPS, Satellite radio, video monitors, hard drives for MP3, USB ports, etc

Installation Tips Plan out where all of your components are going to go

Measure the length of wires needed and calculate the correct gauge needed

Always run signal wires and power wires on opposite sides of the car!

Think about running anti-vibration matting to mute any unwanted sounds

Always use rubber grommets when passing through any sheet metal to prevent wire damage/shorts!

Always use correctly sizes fuses to prevent system or component damage!

All done? Not yet.... Here is where people make or break a good sound system Get yourself some audio clip of frequencies for low, mid, and high signals Play them and ensure your crossovers are set properly and that your speakers aren’t clipping Search out and silence any vibrations Clean up any loose wires, visible wires, etc

Questions?