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A tweeter is a loudspeaker designed to produce high audio frequencies, typically from around 2,000 Hz to 20,000 Hz (generally considered to be the upper limit of human hearing). Some tweeters can manage response up to 100 kHz. The name is derived from the high pitched sounds made by some birds, especially in contrast to the low woofs made by many dogs, after which low-frequency drivers are named (woofers).
All dome materials have advantages and disadvantages. Three properties designers look for in domes are low mass, high stiffness and good damping. Celestion were the first manufacturers to fabricate dome tweeters out of a metal, copper. Nowadays other metals such as aluminium, titanium, magnesium, and beryllium, as well as various alloys thereof, are used, being both light and stiff but having low damping; their resonant modes occur above 20 kHz. More exotic materials, such as synthetic diamond, are also being used for their extreme stiffness. Polyethylene terephthalate film and woven silk suffer less ringing, but are not nearly as stiff, which can limit their very high frequency output.

In general, smaller dome tweeters provide wider dispersion of sound at the highest frequencies. However, smaller dome tweeters have less radiating area, which limits their output at the lower end of their range; and they have smaller voice coils, which limit their overall power output.
What can you do to eliminate your dimming headlights?

If your midsize car is designed "factory standard" with an 80-90A alternator, you shouldn't have a problem adding a 700 Watt RMS system to your car without replacing the battery or alternator. A properly functioning charging system should not experience dimming headlights. If you are experiencing dimming headlights, before adding a power cell or capacitor to your system, have a professional automotive parts store check your battery and alternator to ensure they are in good working order. Changing from a wet cell battery to a power cell with AGM technology will limit the stress on your alternator and can remove the dimming light effect, as long as your new system does not have too much of a draw on your alternator.
Car Audio Capacitors With Power Cells
Demonstration Plus example  to define the true functions and benefits.
TypicalMoble AccessoriesConcerns!&?
Typical 2 Farad Capacitor power recombination method to release excessive alternate power draw
Engine Noise
Do You Have A “Whine” Or A Low Hum In Your Speakers Connected To An Amp?
All  noises you hear in your speakers are caused by 1 of 2 problems: Ground Loops and EMI (ElectroMagnetic Interference).
Commonly referred to as “engine noises”, these 2 problems are responsible for ALL “engine noise” problems. These problems are
very common after an amplifier has been added to a stereo system. “Engine Noises” are many times hard to diagnose, especially as
more equipment is added to a stereo system. But, there are some very basic rules of thumb to keep in mind when installing an amp that
may prevent “engine noises” in your stereo system. If you already have engine noise, these tips may help you reduce or eliminate
noises already in your system. Just remember, “engine noises” are usually the result of
installations where the installer did not prepare the system to avoid “engine noises”. The best way to prevent “engine noises” is to think ahead by following these tips.
Ground Loops: Electronic circuits are simply a power source connected to device or load (electronic equipment). In order for the
circuit to operate, voltage from the power source (in mobile electronics that source is the vehicles battery) is sent through wires to the
electronic device or equipment. The device will still not work unless a return wire is connected from the devices “ground” connection
to the power sources “ground” connection or terminal which will complete the circuit path allowing the equipment or device to work.
In automotive applications, the vehicles battery has a thick or heavy gauge battery cable connected to the (+) positive terminal or
battery post that supplies the vehicles electrical system with power. What most people do not see is a similar heavy gauge power wire
connected to the batteries (-) negative terminal or battery post. This cable usually connects to the vehicles alternator (-) negative
terminal or contact then it is bolted to the metal frame of the vehicle itself. In doing this, the metal frame of the vehicle is now the
electric “ground” of the vehicle. A “ground” is simply another word for the (-) negative return path back to the power supplies
(vehicles battery) (-) negative terminal or battery post. Auto makers do this because it effectively reduces the wire run through the
electrical system in half. The auto maker generally only has to run (+) positive voltage wires to components while the (-) negative
ground wires can simply be screwed directly to a nearby metal part of the vehicles body frame. This way the (-) negative ground return
to the battery is carried by the vehicles metal frame, to the heavy gauge battery cable bolted to the frame which will return the (-)
negative ground back to the battery - completing the circuit necessary to make the equipment run.Route power wires and audio cables separately: one of the best, and simplest, tips to avoid EMI problems when installing
amplifiers is to route the amplifiers power wire on the opposite side of the vehicle as the amplifiers RCA audio cables. The
amplifiers power cable should be connected to the battery, run through the metal fire wall at the dash and then run down the
side of the vehicle to the location of the amplifier. Now run the audio RCA cable outputs from the radio down the opposite
side of the vehicle to the amplifiers location. This will assure that the EMI magnetic field generated by the amplifiers power
cable does not induce into the RCA audio cable.
RCA cables: when running RCA cables from the radios output to the amplifier, make sure to avoid possible EMI “hot spots”.
These “hot spots” are usually located around the radio itself (air conditioner, hazard switch, cigarette lighter, etc.) so it is best
to route the RCA cable below the carpet as quickly as possible. Many installers choose to route the first few feet of the RCA
cable under the dash, weaving it through the maze of wires under the dash. This is a sure ticket to EMI problems. When
possible avoid any location where there is a concentration of wires.
Ground Loop Isolators: you might think this belongs in the ground loop section, but ground loop isolators are small devices
that plug in-line between 2 sets of RCA cables. Ground loop isolators, although not always an answer, can many times filter
out EMI noises if the ground loop isolator is installed close to the amplifier. Try the above methods to prevent EMI as well as
the solutions to prevent ground loops before trying a ground loop isolators. All of the other solutions and methods described
in this document are FREE methods and require no additional parts to be purchased. Why purchase a ground loop isolator
when the solution may be FREE.
Safe Sound Pressure Levels (SPL)
Knowing what is a safe sound level, while running Your audio, is probably the largest responsibility of any serious audiphile. Make sure you have the knowledge and tools to measure the pressure levels. Time Vs. Sound Pressure
Damage can be attained thought the length of time. (Unless the levels are surpassed 140 Db, in which a second of this will cause permanent harm). The longer a person is exposed to the level, the worst it will be on their hearing. Below is a chart showing sound pressure levels and the time that it will cause damage.

Hearing damage at virtually any constant level will occur after a period of time. Below indicates the sound pressure level in decibels and the time after being exposed will cause hearing damage.
What Is Too Loud?
The concept of sound and its properties on the human ear, psychoacoustics, is very fascinating. Sound damage to the ear will consist of two points. The time exposed to a given level and the decibel, sound pressure level. Both are important in understanding how sound can damage hearing and how to protect your self and others from the damage. The longer one is exposed to a given level, the faster and worse the effects on the ear will be. I suggest measuring levels sporadically during the first few song practices and during the services. Check out, Safe Sound Pressure Levels, to find out what exacly is too loud. 


Sound levels in all situations should always be conceited and never over looked. For people running sound and even the musicians on stage, the sound pressure level is very important to know.
Acoustic Sound Definitions
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Acoustic Sound Definitions

Absorption - The process of changing sound energy into heat energy with special materials. This will then lower the amount of sound reflected back.

Active - A type of PA speaker that is self powered; meaning that the speaker has a built in amplifier. Opposite to passive speakers.

Acoustical Environment - The features of a given room, influenced by the absorption, refraction and it's dimensions.

Acoustical Material - A fabric like material designed to absorb sound in reflective environments. (ex. gymnasium walls or church sanctuaries…etc.)

Acoustics - The science of sound and its properties/effects on a given environment.

Anechoic - Sound without any echo.

Amplifier - Audio amps (amplifiers) are the units that convert the finished, mixed signals (from the soundboard) into electrically, powerful signals for powering the loudspeakers.

Artificial reverberation - Sound passed through an acoustic or electric process in a common effect known as reverb. This method is used to make a sound/signal more realistic. Effect units may have default settings to simulate the sound in desired places or surfaces like; rooms, plates, concert halls, bathrooms, stadiums…etc.

Attack - The start/beginning of a sound. On a compressor unit, the attack refers to the speed in which the compressor begins to reduce the signal as it passes through the threshold. You will generally see an 'Attack' knob on compressor and gate units.

Attenuate - The reduction of an electrical or acoustical level.

Audible frequency range - Perceptible range of frequencies heard by the human ear. (20Hz to 20,000Hz)

Auditory system - The sensory system in the ear that gives the sense of hearing.

Background noise -
Unnecessary noise from sources not pertaining to the object of significance. Structureborne, airborne and instrument noise are forms of unwanted noise. Background noise can be a cause of sound bleeding from other microphones. To help resolve this, the use of gates will be very helpful.

Bandpass filter - A filter that reduces signals under and above the desired passband.

Bandwidth - The entire frequency range of a system.

Bass - The lowest range of perceptible frequencies starting around 20 Hz.

Boomy - A listening term, that refers to an overload of lower end frequencies.

Bidirectional - Known as a type of pick-up pattern in microphones that will capture sound from the front and back of the diaphragm.

Bright - A listening term, that refers to an excess of higher end frequencies.

Channel balance - In a stereo system, the channel balance refers to the symmetry of sound levels between the left and right speakers. This action, on a sound board, is usually called 'panning'.

Clipping - A type of distortion that can occur when an amplifier is driven into overload. Clipping can happen throughout all the stages of your church PA system; starting from an input on a soundboard, to the final output of the amplifiers/speakers.

Cloud - An acoustical panel suspended from the ceiling to reduce the amount of reflections.

Compression - The process of reducing the dynamic range of a signal. Generally used for vocals, instruments and drums. How to set up compressors.

Crossover frequency - The dividing signal in a speaker of different frequencies

Decibel (dB) - A number represented for the loudness of sound to the human ear.

Digital Delay - Effect which controls the input of a signal and then repeats after a period of time. Delay units have controls for decaying of the echo and reverb.

DI Box - Direct Input Boxes are used to change different impedance levels from instruments to the soundboard.

Dynamic headroom - The ability of a sound device to reach musical peaks.

Echo - A sound that has returned from its original source and was delayed multiple times.

Equalization - The process of altering frequency responses of a device to achieve a desired response.

Equalizer - In a system, the equalizer is designed to change the frequency response of a signal.

Feedback - Unwanted interaction between the speakers and microphones of a PA system.

Frequency - The calculation of fast variations of a periodic signal, expressed in cycles per second (Hz).

Frequency Response - Changes in the sensitivity of a circuit or room with regards to frequencies.

Front of House - The area that the audience (or congregation) has access to. Mainly excluding the stage and behind stage. Normally where everyone sits or stands at a service or show.

Fundamental - The lowest frequency of a note.

Fusion Zone - When all sounds (natural, eclectically generated or reflected) are fused together and heard by an observer’s ears; this will result in the apparent increase in sound level. Also called, the Hass Effect.

Gain - An increase in level. On most soundboards, this is a function knob that enables the input level into a channel.

Hard room - An environment which the surfaces have a very low value of sound absorption and are reflective. Opposite from a soft room.

Headphones - A tool (device) for the ability to hear any specific instruments/channels.

Headroom - The capability of an amp to go past its rated power for short durations without distortion.

Hertz (Hz) - The unit of frequency that means the same as cycles per second. (Abbreviated as Hz)

Impedance - The resistance to the flow of electric energy measured in ohms.

KHz - Kilohertz - 1,000Hz.

Live end dead end - A treatment plan for acoustics that at one end of the environment it is reflective and the other end is very absorbent.

Loudspeaker - An electroacoustical transducer that alters electrical energy into acoustic (audible) energy.

Masking - Adding a presence of sound to one source by another.

Microphone - A device that converts sound waves (acoustical energy) into electrical signals.

Midrange - In a speaker, the midrange is created with a tweeter for high frequencies and a sub-woofer for the low end frequencies.

Monitor (Wedge) - A speaker or in-ear monitor system, used on a stage to send sound to the musicians.

Muting - A dramatic reduction in the volume level. On a soundboard this function is called the ‘mute’ button.

Noise - Interference of either an electrical or acoustical signal. Gates are ideal for greatly reducing acoustical noise on stage.

Octave - In interval multiples of two between the frequencies bands 20Hz-40Hz. Each octave you add on the lower end requires that your speakers move four times as much air.

Omnidirectional - Referred to as a type of pick-up pattern in microphones. Omni, meaning ‘all around’; captures sound from all directions (360°).

Patch Cable - Typically an unbalanced quarter inch (1/4) phone jack used to connect instruments and other devices. Not suggested to be used for powering monitors or speakers.

PA system - Public address system; its purpose to amplify any given source used for communication in public areas.

Passive - A type of PA speaker that is unpowered, so that the speaker needs an external amplifier source, like a powered mixer or a power amplifier, in order to operate. Opposite to active speakers.

Phantom Power (+48V) - A function on most soundboards used to send 48 votts of electrical currents through audio cables. Mostly all condenser microphones require phantom power to work.

Phon - Unit of the audible loudness level of a tone.

Pick-up Pattern - For every microphone there is a property know as directionality. Directionality is described as the microphone’s sensitivity to sound from numerous directions.

Pitch - The perspective frequency of tones.

Psychoacoustics - The science of sound and its interaction on the auditory system.

PowerCon - Used for connecting the amplifiers and speakers in a PA system. The end of the cable has a twist lock feature, to ensure the connectivity of the cable. Has a very similar design to the speakon cable.

PZM Microphone - A special type of condenser microphone that has a plate (flat surface) that vibrates to all sound locations near it. Also called a Pressure Zone or Boundary microphone.

Refraction - Sound that is redirected by a process of bending sound waves through material with different sound velocities.

Returns - A process used with effect units. A signal must be sent to an effect unit and then 'returned' back to the soundboard.

Reverberation - The persistence of sound when enclosed in a space, which has reflective properties, after the source of the sound, has stopped.

Reverberation time - The falling off of a sound in a closed environment because of reflections.

Slap back - A distinct reflection from a nearby surface.

Snakes - Audio snakes are used for carry many signals in a single cable, great for long distances.

Soft room - An environment with highly absorbent surfaces. Opposite from a hard room.

Sone - The unit of measurement used for the subjective loudness on the auditory system.

Sound insulation - The ability of a given environment’s, physical composition, to stop sound from leaving the wanted origin. Different types of insulation have numerous effects on the sound. This sound energy is not necessarily absorbed; however the sound maybe reflected back or the impedance may become mismatched.

Sound isolation - The degree of acoustical separation between two environments. Like a control room to the live recording room. Some headphones are also sound isolating.

(SPL) Sound pressure level - Expressed in decibels as the loudness or volume of a level.

Sound spectrograph - A device used to measure the level, frequency and time of a signal.

Sound waves - Frequency determines the length of waves and the amplitude (loudness) determines the height of the waves.

Speakon cable - Used to connect amplifiers to speakers, generally used in pro audio systems. This connector has a twist lock feature, to ensure the connectivity of the cable. (Similar to the PowerCon connector)

Spectral balance - The balance across the whole frequency spectrum of the system.

Splaying - A physical attribute to an environment where the walls are purposefully constructed off square. This is done to imperfect the flow of returning sound waves. Another method used for reducing echoes.

Stereo - Artificial simulation of natural human hearing by creating a 3-D image through a system of supplying two different sources with slightly singular mixes and sounds. In the case pertaining to a PA system, this would be called the Left and Right channels. For true stereo to be achieved; the soundboard, processing amplifiers and two separate speakers must be available.

Subwoofer - A speaker cabinet created for low-frequency reproduction. The best ability that a subwoofer should reach is into the bottom octave (20-40Hz).

Tangential mode - A physical room atmospheric mode produced by reflections from four of the six surfaces.

Threshold of feeling - Sound pressure that can cause discomfort and pain. Situated around 120 dB above the threshold of hearing.

Threshold of hearing - The lowest sound level that can be heard by the auditory system. (around 20uPA)

Timbre - The superiority of a sound that can be notable from other sounds of similar pitch and level.

Tip-Ring-Sleeve (TRS) - Audio cable ends, generally used for connecting instruments through to the soundboard. Called TRS for its physical features. Tip is the left channel signal the Ring is the right channel signal and the Sleeve is normally the ground.

Tone - Is the result of an auditory sensation of the given pitch.

Treble - The highest of all frequencies in the audio spectrum.

Unidirectional - Referred to as the type of pick-up pattern in microphones that will only capture sound from one direction.

Watt - A unit of electricity and acoustical power. The energy is expressed in intervals of seconds.

White noise (ANS) - An audible noise with a constant frequency spectrum. This is used to calculate and equalize the response of a system.