Scott's PA System Tutorial: Words to Know

Part 1



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This section deals with some words and phrases you are likely to hear and maybe even use while running sound. It helps to be at least somewhat familiar with most of these so that you can better impress you friends with your high tech lingo. Some of the definitions are taken right out of the dictionary, while others are interpretations taken directly from personal experience as a sound man and a musician.


Active/Inactive Microprones - Scientific definitions aside, active microphones generally sound better than inactive ones, but they generally cost more. They also require the use of either a battery or phantom power while inactive mics need only be plugged into the mic cord in order to work. In most playing situations, the subtle improvement in sound quality from an active mic isn't worth the extra cost and hassle. One possible exception it the headset mic. Put simply, inactive headset mics just plain suck. Active headset mics put out a much stronger signal and feed back much less.

Amplifier (Power amp, Head) - It's the part of the sound system that actually magnifies or "amplifies" the sound. In other words, it makes stuff louder.

Attenuator (Pot) - The electronic dohickey under the knobs that increases or reduces the strength of the signal running through it. When these get old and dirty, they can make popping noises or rumbles in your PA (As in "my pots are dirty").

Balanced input/output - A "balanced" connection is one that has three wires to move the signal.  One is a ground, and the other two (called conductors) carry signals of equal value.  This is why they are called balanced. Low Z cables and connections are the most common example.

Balls - 1) The depth and thickness of a sound, usually on the bottom end of the EQ (as in "needs more balls"). 2) The strength of the voice on the mic (as in "check it like you have some balls").

Bass - 1)The lower frequencies. 2) On the soundboard this should refer to the bass guitar channel, not the bass drum.

Bottom - The bass frequencies (as in "needs more bottom end").

Cable, 1/4 inch - An unbalanced cable most often used for instruments and patch cords. Commonly referred to as "guitar cords".

Cable, TRS - A less common balanced cable that has 3 different contacts on its 1/4 inch connectors. Most headphone jacks are a good example of a TRS (Tip-Ring-Sleeve) connector. These are sometimes used instead of the more common XLR connection.

Cable, XLR - A balanced cable used for low impedance microphones and sometimes for connections between some parts of the PA. Commonly referred to as a "mic cord".

Channels - These are divided into two separate categories. Input channels are those channels coming into the soundboard such as microphones and direct lines. Output channels are those leaving the board such as monitor and main outputs.

Chorus - Common type of effect that makes sounds fuller and thicker.

Clean - Describes a distortion free sound with few effects.

Compressor - Effect used to squash the sound together. Used properly, it can take the edge off or your sound. Used improperly, it can take the life right out of your system and make it sound like an MTV mix.

Crisp - Describes a good clean high midrange sound. It can be good or bad depending on the look on the face of the guy who said it.

Crossover, Active - A rack mountable unit used to separate frequencies leaving the soundboard into high's, mids, and lows with different outputs for each.

Crossover, Passive - Used inside of full range speaker cabinets to separate highs, mids, and lows and send them to their respective speakers within the each cabinet. These are not as efficient as active crossovers because they require all frequencies to draw from the same source of amplification.

Cord (Speaker, Mic, Instrument) - Used to connect a sound system together. Each type of cord is made for a specific purpose and should not be used in place of another type of cord, not even if they look alike. Also see "cable"

Delay (Digital, Analog) - 1)Effect used to create echo...echo...echo...echo...echo... 2)In more advanced systems used in very large venues, delay can be used to time the arrival of the signal to the speakers in the back of the room so that people in the back hear the sound coming from those speakers at the same time that the sound coming from the speakers in the front of the room arrives.

Direct box - Used in line to convert a high impedance signal into a low impedance signal.

Distorted - The way your PA sounds just before it blows up. Fuzzy and scratchy. If you hear this, it either means you have something hooked up wrong, or something in the system is going bad. It could be anything from your super expensive soundboard to a five dollar patch cord.

Dry - Describes a sound coming from the PA with no effects on it.

Effects - Electronic boxes (usually rack mounted) added to a PA system to subtly change and enhance the signals going through it. Examples include; Reverb, Delay, Compressor, Chorus.

Equalizer (Parametric,Graphic) - This is used to filter out and adjust specific frequencies in the PA. This is the part of the PA where you have the most control over the band's overall sound. It is also the number one weapon against feedback.

Feedback - This occurs when the sound coming out of the speakers goes back into the microphones, then back out the speakers, then back into the mics.... and so on. This can build very quickly to a point where everyone in the room is holding their ears and screaming at you. It can also cause damage to the PA.

Flat - Refers to the frequencies on the EQ when they are arranged in centered neutral positions.

Folded Horn - A speaker design where the speaker points back into the cabinet and bounces around finally coming out large ports in the front. It is intended to maximize low frequencies in a relatively small cabinet.

FOH (Front of House) - Refers to the speakers that face toward the audience. Also called the "main" speakers.

Frequency - Practically speaking, high frequency means high pitch and low frequency means low pitch.

Front Loaded - A speaker cabinet where the speaker faces out toward the front.

Full Range - Describes a sound which covers all audible frequency ranges. As in "full range speaker cabinets."

Gain - Knob usually found at the top of each input channel on the soundboard. Used to set input levels of the separate channels to relatively equal positions.

Ground Adapter Plug - Adapts a three pronged electrical plug to a two pronged wall outlet. This bypasses the ground and may create a hum in the system. A lack of a good ground can cause mild electrical shock when touching a microphone.

High Impedance Cord (High Z) - A big word for instrument cable. These cords generally have quarter inch male ends. they tend to loose signal strength at lengths longer than 25 feet.

Horn - The part of the speaker that emits midrange and higher range frequencies.

Jack - Anywhere you plug something in.

Kick Drum - PA lingo for bass drum. This eliminates the confusion between the bass drum and the bass guitar.

Level - Sets output volume of individual PA input channels. Usually positioned as sliders at the bottom of the soundboard.

Loop (Effects Loop) - A signal path separate from the main signal paths where a line signal is routed out of the mixer through a series of effects units, and then returned back to the mixer. The electronics within the mixer can then be used to individually control the effects on each input channel.

Low Impedance Cord (Low Z) - A big word for mic cable. These cords lose very little signal over distance, and can thus be made very long. PA snakes are constructed mostly of Low Z cords because of their need to be lengthy.

Line In (Input, return) - Where a signal enters the board or component.

Line Level - A low level signal such as the signal in a guitar cord. Most parts of a PA require a line level signal. Remember, however, that speaker outputs are not line level. Plugging speaker outs into line ins will result in damage to the equipment

Line Out (Output, Send) - Where a signal leaves the board or component.

Mains - The speakers facing the audience along with the system of amps equalizers and effects attached to them.

Microphone (Mic) - I'll bet you already know this one

Monitors - The speakers facing back onto the stage and the system or amps, equalizers, and effects attached to them.

Monitor Mixer - Larger systems often use a completely separate mixer for the monitors that only adjusts the sounds that are heard on the stage.

Muddy - Describes a low end muffled sound lacking highs and mids, and possibly having too much effects.

Pan (Balance) - Knob on the mixer that adjusts the relative volume between left and right (or A and B) in a stereo setup. Just like the stereo in the living room.

Patch Cord - A very short high Z instrument cable.

PFL - These buttons allow you to boost or isolate individual channels in the headphones.

Phantom Power - When this is turned on in the soundboard it will power the active microphones in the system. It should be turned off when no active mics are hooked up.

Polarity - The direction of flow of electricity either negative to positive or positive to negative. Matching polarity between different amplifiers can greatly reduce hum and the risk of elictrical shock. Most amps come equipped with a "polarity switch".

Potentiometer (Pot) - See "attenuator". For our purposes, they are the same.

Power Strip (six way) - Allows you to plug a lot of things into one power outlet.

Power Supply - Basically, a rack mountable power strip that costs a whole lot more, but hey, some of them have cute little lamps that light up the face of your rack.

Reverb - A most basic and necessary effect. Think of it like this. If you stand in a big empty warehouse and shout, "Hey!", you will hear a sort of "reverberation" surround you. It's sort of like an echo, but not exactly. Think of it as audio afterglow.

Slider - Usually found on an EQ of a soundboard. These turn things up or down by a "sliding" movement rather than the rotary movement employed by knobs.

Snake - In large systems, this long bundle of cords connects the things on the stage (amps, mics...) to the things at the sound booth (mixer, effects, EQs.....).

Speaker - The part of the system that physically produces the sound.

Speaker Cabinet - The box that holds the speakers.

Speaker Out - A high power signal leaves the power amp through this jack on it's way to the speaker.

Submix - Used on larger mixing boards when selected channels are assigned to specific sub-channels before their signals reach the main slider. For Example, you could assign all the drum channels to one submix (all on one slider) so that you could turn them all up or down at the same time.

Sum - This sends a line level signal out of the board. Heck if I've ever found much of a use for it.

Tinny - Used to describe a sound with too many highs and mids and not enough lows.

Unbalanced Input/Output - These cables contain 2 wires inside of them. One is a ground (shield) and the other carries the signal. The most common of these for PA uses are the 1/4 inch high Z instrument cables and connections.

This part of the tutorial is an on going project. If you have any words you think should be added, please send your suggestions to the address below....August,1998

PA Home Setting it up Running Sound Tips and Tricks


Any suggestions? Comments? Mail me at Bassist@Spydee.net.

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