Live Sound Mixers

Live Sound Mixers

Electronic signals from microphones and instruments need to be balanced, processed, and mixed together before they can be amplified and routed to PA speakers and monitors. In your live music PA, this is where the mixer comes in.

Mixers range in size from simple 4-channel units to much larger consoles that have hundreds of channels. A channel is essentially a signal path. A mixer with a large channel count allows more things to be connected and routed through it.

Channels are usually designed to accept microphones and/or line-level devices such as amplifiers, preamps, or signal processors. (Microphones and instruments such as guitars and basses output electronic signals that have a much lower level than line-level devices.)

On a mixer, audio signals are assigned to separate channels, so a fundamental question to start narrowing down your mixer selection is “How many channels do I need?” Generally, you will want to make sure you have more channels than you think you will require. So it's important to take an inventory of what you will be amplifying and make sure you have sufficient inputs and outputs while allowing for future expansion of your PA system.

For instance, if you are plugging a standard five-piece rock or pop band in to your PA, your first instinct might be to shoot for an 8-channel mixer. After all, that would allow for five instruments with room to spare. However, once you add up the inputs for everything you need for the group, you will find that your 8 channels actually won't give you enough inputs.

With a five-piece band, the live sound arrangement might look something like this: one mic for lead vocals and one for backup (two channels), one mic for the guitar amp, one for the bass amp, and at least one direct input for synthesizers (three channels). Then there's the drum kit, which will have its own miking considerations. With two overhead mics for cymbals, a mic on each tom, the snare, and the bass drum, you are looking at a minimum of seven mics for a fully miked kit.

This brings your total required inputs to 12 channels, so you’d want a model with a minimum of 16 channels giving you room to expand.

Getting to know the mixer

Learning to use a mixer might initially look like a daunting task, with all the buttons, knobs, and faders. But keep in mind that every channel has the same controls. Once you learn how to control one channel, you'll know how to control every channel.

Every channel on a mixer is either mono or stereo with an XLR, 1/4” or RCA connection. (Some inputs are designed to handle both XLR plugs from microphones as well as 1/4” inputs.)

A channel strip is a group of circuits and controls that function together on a given mixer channel to affect the audio signals that pass through it. These usually include:

• an input jack where an external instrument, microphone etc. connects to the mixer. XLR inputs are balanced to minimize noise and interference. Other inputs accept RCA or quarter-inch TRS connectors. Some accept both XLR and 1/4” plugs
• a microphone preamp that prepares the relatively weak mic signal for processing by raising it to line-level strength
• equalization, abbreviated as EQ, adjusts the signal’s frequency response in three or more bands
• dynamics processing that may include compression or gating (discussed below)
• routing that directs the signal to other mixer buses and external devices
• stereo channels include a pan control for balancing left and right output
• a fader, which slides along a track to control the input or output level of a channel
• a meter or light display that visually shows the output of each channel

Getting more control from a mixer

If you want to be able to make quick adjustments to your mix during a live performance without throwing things out of balance, look for mixers that offer multiple buses.

Basically, once the levels of each channel are set, the signals are combined into either the main mix or into submixes that can be assigned to buses. Buses can be visualized as circuit intersections where the output from several channels meet. Each mixer channel routes its signals to a specific bus or group of buses. These buses allow you to adjust signals as a group before they go into the final mix and out to the speakers. So, for instance, you can easily make adjustments to all the vocals or all the drums using a single group fader control. Also known as auxiliary sends, auxiliary buses can also be used to route mixes to headphones, external effects processors, monitor speakers, or in-ear monitors.

You can also make additional enhancements using buses. For example, two-bus mixers normally have a pan control to send a signal to the left or right bus, creating a stereo output. There also may be insert points where you can apply effects to buses before the final mix.

The Yamaha MGP16X Mixer has 16 channels and four buses, allowing you to assign groups of channels to a specific bus for effects processing or overall control of all assigned channels using a single fader.

Digital vs. analog PA mixers

For instant changes to signal routing, flexible and extensive signal dynamics, and an amazing array of effects possibilities, a digital mixer is hard to beat. With the touch of a button, pre-programmed routing and effects can be triggered that would be impossible for even a talented octopus to accomplish on an analog audio mixer!

Some digital mixers are compatible with software plug-ins that extend their tone-shaping capabilities even further. Recently, many digital mixers have added mobile-device compatibility, allowing operation via a laptop, smart phone, or tablet.

Our expert Audio Interface Buying Guide will help you choose the right gear to control mixes with your computer or mobile device.

Digital mixers can also can ride herd on dreaded feedback, preventing the howls and squeals before they even start. Another nice feature is automatic gating that silences channels with little or no signal passing through them.

One of the huge advantages of digital mixers is their ability to save and recall mixes. Many use USB flash drives or internal memory to store settings from past performances. This makes the set up in a venue that’s been saved fast and simple. Even in a new venue, recalling mixes from similar venues can be a big time saver during sound checks. Some digital mixers let you pre-program mixes using a laptop computer, so when you get to the gig only fine-tuning tweaks to the sound are needed. Some advanced digital mixers have motorized faders that respond to saved configurations.

Despite the greater versatility of their digital brethren, analog mixers remain popular due to their generally lower cost and ease of use. Since their functions are controlled by physical knobs, faders, and switches, their operation can be somewhat more intuitive than digital mixing consoles. The downside of their reliance on physical controls is the analog mixer’s generally larger footprint—a disadvantage on cramped stages. Many people find the analog mixer’s signal and hardware routing easier to grasp at a glance since everything is physically present rather than being hidden in the menus of a digital soundboard’s many status screens.

Both analog and digital mixers are capable of transmitting very high quality sound. The quality and design of their electronic circuits—especially the mic preamps—and in the case of the digital mixer, its analog to digital converter (ADC), have the biggest influence on sound quality. Most sound engineers agree that mics and speakers with their inherently greater degree of coloration and distortion are the biggest barriers to absolute sound fidelity. That said, well-designed mic preamps that boost the microphone’s output without adding coloration or distortion are critical to good sound. High-quality circuitry and components in the mixer’s gain stages and signal routing will minimize the hiss that inevitably occurs with analog mixers.

Browse the huge selection of analog and digital audio mixers at Musician’s Friend.

Powered or unpowered?

When you browse the Musician's Friend assortment of audio mixers, you'll notice that we group powered mixersand unpowered mixers separately to simplify shopping There is only one major difference between these types: Unpowered mixers require one or more separate power amps, while powered mixers have on-board amplification.

Powered mixers are often easier to transport, less difficult to set up, and are often less expensive. But on the downside, they may offer less power than standalone amps, so they are unlikely to work well in larger venues. And as noted before, powered mixers tend to offer less sophisticated control and fine tuning of sound than non-powered mixers.

Additionally, buying powered mixers might be less cost-effective in the long run if you plan to make gradual upgrades to your PA system. That's because you will be replacing both the mixer and the amp when you want to upgrade either component.

Do I need another mixer for monitoring?

In addition to the main, front-of-house (FOH) mix, you will want your PA system to handle monitoring so the performers can hear themselves. For this, you have a couple of options.

Often, a single mixing board is used to create not only the main mix, but also the individual mixes each performer needs to hear through the monitors. These mixes will need to meet the different requirements of each performer, according to what each player needs to hear.

Monitor mixes are typically delivered using the aux send connections on the mixing board. To ensure you and other performers are getting a good mix for performing, you'll want to confirm that the mixer has sufficient aux sends to route individualized monitor speaker mixes to each performer.

Another option for those serious about monitoring is to have a secondary mixing console dedicated to the task. Sure, it's an additional investment, but it can be worth the expense for the quality of sound delivered to the performers.

Learn more about live sound and recording mixing consoles with our expert Mixer Buying Guide.

Signal Processing (Effects)

Mixers may have some built-in effects, but if you really want to make your sound stand out, additional outboard processing gear can help add drama and sparkle to your sound. Although they're not essential in all situations, signal processing and effects such as compression, limiting, reverb, and delay can add sonic interest to your sound that make them well worth the cost.

Here are some basic effects and signal processing tools that can enhance your PA system:

Compression and limiting

A compressor as the name suggests compresses the overall dynamics of the audio signal limiting the amount of variation between the loudest and softest sounds.It smooths your sound and protects gear by helping to avoid damage caused by clipping—a speaker-destroying phenomenon resulting from overdriving the amplifier into distortion. Well designed compressors not only prevent signal distortion, but add pleasing sustain to your sound.

The dbx 166xs has both compressor and limiter functions to smooth out live sound by producing tighter mixes and fattening up drum sounds.

A similar tool, the limiter keeps your speakers and ears from getting blown out by limiting the peaks in the music. A limiter allows compression to occur only above a set threshold, and the compression ratio can be very high. This prevents clipping, distortion, and other related problems.

Reverb and delay

Reverb (from reverberation) is an effect that makes sounds richer, as if they are reflecting off surfaces. Reverb adds depth and dimension—that’s why your voice sounds better when you sing in the shower. The hard, reflecting surfaces add “space” and drama to your vocal performance. The adjustable parameters on a reverb unit allow you to control these reflections to simulate various acoustic environments.

Delay is one or more echoes that have a more distinctly audible space between the initiation of the original sound and its reflection. There is a more distinct repetition of the original sound (partial words, musical phrases, etc.) and an eventual diminishing of volume over time. Delay is the effect you experience when you shout into a large canyon: your voice bounces back to you in diminishing waves.

The TC Electronic D-Two Multi-Tap Delay offers a wide selection of delay types up to 10 seconds in length and is easily programmed to match your rhythm tempos.

Other common processors

Sonic enhancers such as the BBE Sonic Maximizer give your sound more presence by delaying the low frequencies relative to the higher ones, removing subtle inaccuracies in timing to preserve the sonic characteristics of live instruments.

The BBE 382i Stereo Sonic Maximizer enhances high- and low-frequency to help clarify and add punch to your sound.

There are many other processors that offer a huge selection of sound-shaping options to meet all your effects needs. Browse the huge selection of signal processors at Musician’s Friend.

Equalizers

Most mixers include an EQ section. The most simple mixer equalizer controls resemble those found on consumer electronics and typically raise or lower the low, mid-range, and high frequencies. More advanced mixers offer more fine tuning of frequencies as discussed below.

The important role of an equalizer is to balance out your sounds by allowing you to boost or cut highs, lows, and mid-range frequencies to improve your overall sound. The equalizer modifies the signal's frequency response by increasing (boosting) or decreasing (attenuating) selected ranges of frequencies. Equalization also can help fight feedback by letting you pinpoint and reduce the volume of frequencies where it occurs.

The built-in equalization circuits in your mixer may be adequate for fine-tuning your overall sound. But for the most demanding sound applications, a standalone equalizer will likely do a better job.

Types of equalizers

There are three types of equalizers commonly used with PA systems.

Parametric EQ: Parametric equalizers give you the most flexibility in sound shaping, but are more challenging to use. Unlike graphic EQs that only let you set the amount of boost and cut, parametric EQs allow you to set the gain, center frequency, and the bandwidth of a given frequency. The range of the bandwidth is referred to as the Q factor. Parametric equalization controls the relative cut or boost of the signal above and below the center frequency. With practice, parametric equalizers are powerful and flexible tools for helping specific instruments or voices to cut through the overall mix, or to generate a big, full sound.

Semi-parametric/quasi-parametric EQ: These function in the same way as a parametric EQ, however the manufacturer sets the bandwidth—it's not user-adjustable. These units trade off somewhat easier operation with reduced functionality.

Graphic EQ: Graphic equalizers provide more flexibility and control than simple two- or three-band tone controls, and they're quite easy to use. A graphic equalizer is a set of band-pass filters that divide the audio spectrum into 30 or more bands allowing you to control the amount of boost or cut in much narrower frequency ranges. Usually controlled with sliders, the effect of the equalizer is graphically depicted by the positions of the sliders—that's why it's called a “graphic” equalizer. The ease of use offered by graphic equalizers is largely due to the ability to easily visualize how equalization is affecting the overall audio signal by simply looking at the faders.

Graphic EQs are great for sound reinforcement and “tuning” rooms—adjusting the contour of your sound to match the environment. For example, if you’re performing in a space that produces a lot of boominess, you can cut the lower frequencies that are contributing to the problem. Graphic equalizers allow you to produce a consistent sound at every venue.

Learn more about how equalizers work with our What is an Equalizer Tech Tip.

How is feedback caused?

That awful noise is the result of a feedback loop. This happens most commonly when your sound travels from the microphone to the mixer to the amp to the monitors, then back into the mic. Instead of just making the signal louder as you might think, the sound frequencies boosted by the loop will be amplified hundreds of times in a fraction of a second, making the squealing, howling noise known as feedback.

The resonant frequencies in a room also can produce feedback. Some rooms tend to overemphasize certain frequencies, and if these happen to be in the range of your vocals or guitar (which is often the case), you’ll have a problem. Certain instruments, such as acoustic guitars, also suffer from the same problem.

The Behringer ULTRAGRAPH PRO FBQ1502 is a 15-band stereo graphic EQ that includes a feedback detection system to instantly eliminate those embarrassing squeals.

Crossovers and Speaker Management Systems

The wide range of frequencies produced in your performance can be better controlled if they’re divided into frequency ranges and sent to the specific speakers designed to handle those frequencies. These speakers (or drivers) can be combined in one speaker cabinet (referred to as full-range speakers) or in separate units. It's the role of a crossover to route these frequencies to the different speakers.

The BBE Max X3 Crossover offers two-way stereo and three-way crossover functions and helps helps tighten and clarify your overall sound with its a built-in Sonic Maximizer.

Two-way crossovers divide your signal between high and low frequencies; three-way crossovers split the high, mid and low signals routing each to its designated driver. The high frequencies are sent to the tweeters, the lows are sent to the woofers and the mids are sent to the mid-range drivers.

What's the difference between active and passive crossovers?

If the crossover is built into your full-range speaker cabinet, it's a passive crossover (in some models, it can be bypassed if you decide to use an active crossover). The crossover is activated when the signal passes through it using inductors and capacitors to divide and send the signal to the appropriate speaker drivers. An inductor responds to low frequencies and sends them to a woofer, while a capacitor picks up high frequencies and sends them to the tweeter. A mid-range crossover uses a capacitor and an inductor (called a band-pass filter) to set upper and lower cutoff points to send this signal to the mid-range driver.

Active crossovers are placed before the power amps and split the signal to send each frequency range to its own amp. It is easier to adjust the frequency ranges sent to each driver with an active crossover. If the active crossover splits the signal between two amps, this is called biamping (two-way); if it's split three ways, it's called triamping (three-way).

What are the benefits of a speaker management system?

Speaker management systems such as the dbx DriveRack PA2 are designed to be everything you need between your mixer and speakers. Features like auto EQ, a pink noise generator, crossover, limiting, compression, etc., can make sound checks, feedback control, and level setting much easier. These systems, typically used by pros and in large touring systems, are becoming more and more common for entry-level users for overall dynamic control.

The dbx DriveRack PA2 combines crossover, EQ, compression and delay control in one easy-to-use box.

PA Speakers

Once your mixer, signal processing gear, and power amp have shaped your audio signals, it's your speakers' job to turn those signals back into physical sound waves. Speakers reinterpret the signal by using the voltage from the amplifier to move their cones back and forth, producing the sound waves that reach the audience’s ears.

Maybe it goes without saying, but speakers play a critical role in delivering quality sound to an audience, and it’s an area where quality gear can make a real difference.

As is true for the power amp, the size of the venue you play will help you decide on the power handling (wattage) and size of the speakers will need. For example, smaller gigs, conferences, and lectures may require about 350-500 watts, while club bands, garage bands, and mobile DJs may need 500-1,000 watts, or even more, depending on the venues they perform in.

Weighing in at 61 lb., the JBL JRX215 passive PA speaker is a two-way system with 15” low frequency driver and 1” tweeter and a built-in crossover. It handles 250W of continuous power.

In choosing PA speakers, the key trade offs to consider are portability versus performance. While full-range speaker cabinets that contain a woofer, mid-range driver, and tweeter are more portable and easier to set up, they typically won’t deliver the same performance as high-end speaker arrays.

Weighing in at a hefty 101 lb. each, this pair of Yamaha C215V speaker cabinetshave dual 15” woofers and compression drivers mounted on horns to handle high frequencies. Best used in permanent installations, they handle up to 1,000 watts of continuous power.

What type of individual speakers are there?

Speakers are designed to reproduce specific frequency ranges. So-called “full range” speaker cabinets usually contain a woofer and tweeter and are referred to as a two-way system. Some PA speaker cabinets also include a mid-range driver and are referred to as three-way systems.

Here are the individual type of speakers and their characteristics found in PA systems:

• Woofer: Reproduces low frequencies, usually with a 10”-18” cone-type driver
• Frequency range: Usually below 500Hz

• Mid-range: Reproduces mid frequencies, sometimes with a 5” to 12” cone-type driver, sometimes a 2-1/2” to 4” compression driver mounted on a dispersion horn
• Frequency range: Generally between 200Hz and 3kHz

• Tweeter: Reproduces highest frequencies with a 1” to 2” cone-type driver or a 1” to 4” compression driver
• Frequency range: Usually between 2kHz and 20kHz

• Subwoofers: Reproduce the lowest frequencies with 15” to 24” cone-type driver
• Frequency range: Rarely above 300Hz down to 30Hz or lower

Should I get powered (active) or non-powered (passive) speakers?

For those who want to avoid purchasing one or more dedicated power amps for their PA systems, powered speakers are a popular option that integrate amplifiers directly into their cabinets. Using powered PA speakers means you can also use non-powered mixer. Powered speakers are a great option for musicians who play at smaller clubs and other venues. They offer greater portability and reduced setup hassles.

The Peavey PV115D Powered PA Speaker has a 15” heavy-duty woofer, 1.4” compression driver for high frequencies, and is driven by an internal 400 watt amp.

The trade-off is that powered speakers provide less flexibility and control over a PA system than separating the power amp from the speakers. Typically, the largest speaker systems designed for bigger performance spaces are non-powered. For this reason, many professional live sound engineers prefer passive speakers that can be configured and positioned to optimize their sound in specific venues.

To make shopping for PA speakers easier, the Musician’s Friend website offers separate assortments of passiveversus powered models.

Should I add a subwoofer?

Subwoofers are the large speakers that handle the lowest bass frequencies. They are not integrated with full range enclosures both due to their size and the potential damage that can be caused to other components by their strong vibrations.

Adding a subwoofer will of course make your PA less portable overall. Unless you opt for a powered subwoofer, you will also need a power amp capable of supplying the wattage required by power-hungry subs. Bands that play heavy rock, metal, reggae, hip-hop, and other styles that depend on powerful bass and drum sounds are most likely to want to include a subwoofer.

As with other PA speaker cabinets, you’ll find a large assortment of passive unpowered and active poweredsubwoofers available at Musician’s Friend.

With 400 watts power handling and an 18” driver, thePeavey PV 118 Subwoofer reproduces frequencies down to 40Hz to bring out the full chest-pounding bottom notes of bass guitars and kick drums.

PA Monitor Speakers

Musicians need to be able to hear themselves and other performers clearly to sound their best, which is why stage monitors are essential. While floor monitors can cause feedback and increase the risk of hearing damage, they are preferred over in-ear monitors by many performers because they are easier to use. These usually wedge-shaped speakers allow performers to hear themselves and play better because of it.

The popular Yamaha A12M Floor Monitor has a a 12” woofer, 1” high-frequency horn, and handles 300 watts of continuous power.

The in-ear monitoring option

Wireless in-ear monitors allow performers to move more freely around the stage and to hear an individualized mix. They eliminate monitor feedback worries, potential hearing damage, and the stage clutter of floor monitors.

The Shure PSM 200 Wireless Personal Monitoring System includes a transmitter, receiver, and earphones for a complete monitoring solution that delivers excellent sound quality.

Learn more about in-ear monitoring with our expert Wireless Systems Buying Guide.

How wiring speakers in parallel or in series affects PA requirements

When you're pairing your power amp or powered mixer with your speakers, you know you need to match the ohms rating on the equipment. However, depending on whether you wire multiple speakers in series or in parallel effects those requirements. So before you buy your gear, you'll want to be aware of how this works.

Wiring a speaker system in parallel will decrease the amount of ohms (and thus resistance). A typical two-way PA speaker is rated at 8 ohms. If you wire two speakers in parallel, the impedance will be 4 ohms; three will be about 2.67 ohms; and four will be 2 ohms. Although a smaller impedance rating means the electricity flows more easily, some amps can't handle a 2-ohm load, so be sure to consult your manual before connecting your speakers.

Wiring a system in series, on the other hand, will increase the impedance by adding the ohms together to create more resistance. So, if you wire two 8-ohm speakers in series, the load will be 16 ohms. If you have some identical speakers with lower impedance than the amp can handle, a series circuit can come in handy to raise the impedance.

Microphones

Almost every PA system will need mics. With so many types to choose from, you may want to consult the Musician's Friend Microphone Buying Guide to get familiar with the basics.

There are two major microphone types: dynamic and condenser. Dynamic mics are durable, reliable, and made for onstage use. For vocals you will likely want one similar to the legendary Shure SM58.

The Shure SM58 is among the most popular onstage dynamic mics thanks to its bulletproof construction, excellent audio performance, and its versatility in capturing everything from vocals to guitar cabinets.

Condenser mics are made to capture more subtleties, handle high sound pressure levels (SPLs) and capture fast transients. They are usually used for recording, but can also be perfect for live sound. They’re often positioned above drum kits to capture the sound of cymbals. Condenser mics require phantom power, so you will need to ensure that your mixer includes sufficient phantom-powered inputs.

The Blue enCORE 300 Condenser Vocal Mic is designed for highly detailed reproduction of the voice and is built to withstand hand-held use onstage.

To minimize feedback, you also will want a mic that is unidirectional (as opposed to omnidirectional) for vocals and instruments. Unidirectional mics are available with cardioid, supercardioid, and hypercardioid pickup patterns. Cardioid mics are ideal for live sound situations because of their wide, forgiving pattern.

Read our expert Wireless Systems Buying Guide for all the details.

If you decide to use condenser mics in your system, they usually require phantom power, which means the power needed to run the mic must be delivered from another source, usually the mixer or a mic preamp, through the mic cable, or from a separate standalone phantom power device. If you buy a phantom-powered mic, make sure you have a power source available.

Wired or wireless microphones?

Ask yourself how much you'll be moving around onstage. Will there be audience participation? Will you be moving off the stage? If so, you probably need a wireless mic setup.

If not, wired mics are more affordable and are more likely to come with PA system packages. Also, you can plug in as many as your mixer can handle without the risk of interference sometimes present with wireless systems. Using wireless mics and in-ear monitoring systems also adds complexity to your gig setup process.

Cables and Other Live Sound System Essentials

Cables carry the audio signals through your sound system. They should be carefully selected to ensure your sound remains clean from the source to the speaker.

In most cases, you'll need balanced XLR microphone cables and/or TRS (stereo) 1/4” cables for live sound, as well as unbalanced 1/4” connectors that are typically used for instrument cables. Balanced cables eliminate the noise from lights and other electronic sources often referred to 60-cycle hum.

Speakon connectors have rapidly replaced 1/4” connectors in many systems due to their ability to lock the jack to the plug, preventing accidental disconnection.

For speaker cables, the larger the conductor size, the better the ability to carry the much higher current required to drive speakers. Also, the thicker the jacket, the better it'll hold up. Place the power amp as close as possible to the speakers and use the shortest cable possible to maximize efficiency.

Instrument cables and speaker cables are not interchangeable. Speaker cables are not only thicker, they are constructed differently, so substitutions can lead to damaged gear.

Browse the huge selection of instrument, microphone, and ¼” cables, plus cable snakes and cable adapters at Musician’s Friend.

You'll most likely also want to get a snake, which is a multichannel audio distribution system that allows you to run a large number of inputs from, for example, the stage to the mixer without using many individual cables.

The Live Wire Advantage 16-Channel/4-Return Snake eliminates onstage cable clutter by routing connections through a box to a single cable running from the stage to your mixer.

Other PA essentials

We highly recommend getting a cable tester. If your system isn't working correctly, a cable tester can save you hours of troubleshooting. We also recommend that once you find the defective cable, you immediately throw it away rather than putting it in a box to be accidentally used again someday, only to find that it (still) doesn't work.

You may also want a dB meter; many venues require that you don't exceed a certain volume level, and a dB meter will let you accurately monitor your volume.

Browse the complete selection of cable testers and dB meters at Musician’s Friend.

If your PA system is not being installed, you'll need some heavy-duty cases or bags to transport your gear. Well built, durable cases are essential to protect your valuable equipment.

Speaker stands and brackets are another must-have accessory. Make sure to get sturdy, reliable nonskid stands that are strong enough to hold your gear securely. Check out the individual adjustability of each stand and make sure it will get your gear into an optimal position. Read specs to ensure the stands are rated to handle the weight of your speaker cabinets.

Microphone stands are also an essential accessory for most PA rigs. You’ll find a broad range of mic stands designed to position mics for vocalists, instruments, and speaker cabinets. Choose designs with stable bases/tripods that will rest being easily knocked over during performance. Mic stands with adjustable booms allow more flexible placement.

If you want to learn more about how to run a PA system, we have many great reference books to further your live sound system knowledge.

Tips & Tricks

Here are a handful of tips and tricks that will help you get the most out of your PA system:

• When pairing speakers on each side of the stage, place them in an arc configuration to widen sound dispersion, allowing the speakers to act like a single cabinet with a greater coverage area.
• Never use your elbow to coil cables as it will ultimately damage them. Gather them in a figure-8 shape instead.
• Use cables with the right gauge wire. Find the minimum recommended conductor gauges below:

Load	Less Than 100'	More Than 100'
16 ohms	16 gauge	14 gauge
8 ohms	14 gauge	12 gauge
4 ohms	12 gauge	10 gauge

• Don't forget that the power amp is the last thing you turn on when powering up and the first thing you turn off when powering down your PA system. This prevents potential damage to connected equipment and subjecting your audience to noise.

What terms should I know when buying PA equipment?

It’s important to know what you’re talking about before you buy! Here are the core terms you should know when looking at any PA system.

• Continuous program power handling: The level of long-term average power the speaker will handle. This spec is sometimes given (somewhat incorrectly) as RMS power (see RMS below).
• Dynamic range: The difference between the loudest and softest parts in an audio signal (usually measured in dB).
• Frequency response: Refers to the range of frequencies gear will accurately reproduce from input to output. The range of human hearing is 20Hz-20kHz. When reading frequency responses, the spec may refer to the tolerance—the maximum level the output will differ from the input. If not specified, the tolerance is probably a standard ±3 dB.
• Peak power handling: The maximum instantaneous, short-term power the loudspeaker can handle. This is a less critical spec than continuous program power handling, and sometimes is used to create a more positive impression of speaker systems.
• RMS (root mean square): The square root of the average (mean) of the squared values of all the instantaneous voltages on a waveform. RMS ratings of speaker power handling are fairly conservative. Continuous program power handling is sometimes—though technically incorrectly—called RMS.

To learn more, read our Tech Tip: Audio Gear Specifications—What They Do and Don’t Tell You

Glossary

1/4" Jack: also known as phone plug. Unbalanced connection using a phone-patching cord connector. The most basic connection in audio

Amplitude: the strength of an audio signal, measured in dB, at a given point in time

Attenuation: the loss or reduction of amplitude of a signal

Auxiliary Bus or Aux Bus: a bus dedicated to transmitting audio signals separately from the main bus. See also Bus

Balanced: an audio circuit with two shielded conductors with reverse polarity and equal at ground. Balanced wiring provides noise-free transfer of audio in areas susceptible to noise, like recording studios and live sound venues. Requires balanced I/O and balanced cables

Band: portion of the frequency spectrum

Biamplification or Biamped: the practice of using separate power amplifiers to drive a woofer and a tweeter in a loudspeaker. Often combined with active amplification, where the amplifier is built into the speaker cabinet

Board: slang for mixing console

Bus: an electrical circuit that transmits audio signals from one or more sources to one or more other sources. The path an audio signal travels in a mixer

Cardioid: heart-shaped microphone polar response pattern ideal for live sound

Channel: a single path of audio through a mixer, processor array, recording channel, or computer interface

Clipping: when the peaks of the signal's sound wave are cut off due to the inability of an electronic device to accommodate the current or voltage, causing distortion

Compression: a reduction in gain or dynamic range of a signal by a compressor. Compression can be used to even out an erratic signal, fatten up sounds, extend sustain of a guitar, sweeten vocals, or push certain sounds forward in the mix of a song by increasing the overall level

Compressor: a unit that applies compression to an audio signal, usually with controls for sculpting exactly when and how much compression is applied to the signal

Continuous program power handling: the level of long-term average power the speaker will handle. A worst-case spec that represents maximum heating that the speaker's voice coils can withstand

dB/Decibel: a logarithm that describes the ratio of two powers (1/10th of a Bel). Some approximate reference points: a normal conversation has a decibel level of 60dB, a ringing telephone is 80dB, shouting in the ear is 110dB, and a jet engine during takeoff is 150dB

Delay: one or more distinct echoes that have a more distinctly audible space between the initiation of the original sound and its reflection and an eventual diminishing of volume over time

Dynamic range: the difference between the loudest and softest parts in a song (usually measured in dB). See also SPL (Sound Pressure Level)

Enhancer: also called an exciter. A signal processor that uses frequency analysis, compression, EQ, and filters to add sparkle to audio. Used frequently to bring certain aspects of a song forward in the mix

EQ: short for equalization. Usually refers to an equalizer circuit that provides control over the frequency response of an audio signal that passes through it. Can be used to shape sounds to be more desirable or cut out undesirable sounds within an audio signal

Exciter: also called an enhancer. A signal processor that uses frequency analysis, compression, EQ, and filters to add sparkle to audio. Used frequently to bring certain aspects of a song forward in the mix, especially during mastering

Fader: a sliding lever that typically adjusts levels. Has the same function as knob-based controls but provides a smoother response, more fine-tuned control, and visual feedback for quickly determining level

Filter: an audio circuit that reduces the level of frequencies outside a preset range

Frequency: the rate of variation of a wave or signal

Frequency range: the set of frequencies a piece of audio gear is capable of handling with accuracy. Uses a specification such as 20Hz-20kHz

Frequency response: refers to the range of frequencies gear will accurately reproduce from input to output. The average person can hear frequencies from about 20Hz-20kHz. When reading frequency responses, the spec may refer to the tolerance—the maximum level the output will differ from the input. If not specified, the tolerance is probably a standard ±3dB. The spec (20Hz-20kHz ±3 dB) means that for a given input signal, the listed range of frequencies (20Hz-2 kHz) will produce output within the specified range of levels (±3dB). As an example, the frequency response of a Shure SM57 microphone is a vocal-tailored from 50Hz to 15kHz

Gain: amplification

Gain-before-feedback: the total amount of volume possible before feedback occurs

Headroom: the difference between the highest signal possible without distortion and the average signal level through a system

Hertz (Hz): frequency in cycles per second

Hi-Z: short for high impedance. Z is a popular abbreviation for impedance, hi is simply a shortened version of high. Usually refers to a 1/4" line input with high impedance, typically several thousand ohms or more. Often provided as an input on a mixer, multitrack, or computer audio interface for a guitar or bass

Hypercardioid: even narrower polar pattern mic than supercardioid for the greatest side-to-side rejection of stray, unwanted sound sources

I/O: short for inputs/outputs

Impedance: the resistance of a circuit to the flow of alternating current, measured in ohms. In audio, impedance is typically classified as low or high and often referred to as Lo-Z or Hi-Z

Inverse square law: the mathematical relationship of the signal strength and distance, where signal strength is inversely proportional to the square of the distance

Level: the amplitude/strength of a signal

Limiter: a signal processor that controls the dynamics of an audio signal. Works similarly to a compressor and often used in the same way, but a limiter establishes an absolute output level threshold and prevents any signal that enters from breaking that threshold

Mixing: the process of using a mixer, either hardware or software, to adjust levels and EQ of an audio performance or recorded audio in an effort to pleasingly enhance and balance the audio

Noise: undesirable or unwanted sound which is introduced to an audio signal by other electronic equipment or excessive gain. Includes hum, hiss, and interference

Ohm: one ohm is the measure of electrical resistance in a circuit when one amp of current is flowing with one volt being applied to the circuit

Omnidirectional: microphone polar pattern that picks up sound from every direction

Peak power handling: the maximum instantaneous, short-term power the loudspeaker can handle

Phantom power: DC voltage usually between 12 and 48 volts applied to an XLR mic input to power condenser microphones. Often mixers, preamps, and audio interfaces have phantom power built in. Outboard phantom power supplies are also available

Phone plug: also known as 1/4" jack. Unbalanced connection using a phone-patching cord connector. The most basic connection in audio

Pink noise generator: makes a sound like a rushing waterfall, meant to reproduce all the sounds that will go through your system during a show by exciting all the audio frequencies with equal energy per octave. Used to test a PA before the show, some mixers have a built in pink noise generator

Polar response pattern: graphical representations of a mic's pickup pattern

Power amp: a device that increases the power of an audio signal by matching the input to the output of a regulated power supply. In live sound, power amps are used to amplify the processed and mixed signal providing power the speakers

Power conditioner: an electronic device that sits between a wall outlet and electronic equipment, which provides protection against spikes and surges in power. Typically conditioners also provide some type of noise filtering against electronic signal interference

RCA connector: more correctly called a phono plug, this connection was developed and popularized by the RCA corporation in use with their audio equipment, resulting in it being called RCA. Most often used in stereo pairs and more common in consumer audio gear

Reverb: a series of multiple sound reflections that extend the impact of the original sound. In nature, this is caused by a sound that originates within a space enclosed by hard surfaces. Also refers to the electronic equipment developed to replicate this acoustic phenomenon

RMS or root mean square: the square root of the average (mean) of the squared values of all the instantaneous voltages on a waveform. Continuous power handling is sometimes—though technically incorrect—called RMS

Signal-to-noise ratio: the ratio of the desired signal's volume to the unwanted noise, usually measured in dB. Manufacturers measure this ratio in many different ways, but basically the higher the number, the better and cleaner the signal

Signal processor: generic term which loosely describes components such as compressors, limiters, EQ, microphone preamps, noise gates, reverbs, chorus, delays, modulation, filters, and enhancers/exciters. All are used in audio to process sound in order to achieve a desirable effect

Slew rate: the amplifier's ability to react to quick changes in signal voltage. For amps rated up to 100W continuous, the slew rate should be at least 10V per microseconds. For amps over 200W continuous, it should be at least 30V per microsecond

Sound Pressure Level (SPL): the level of acoustic sound waves, measured in dB. A typical SPL reading for a rock concert is 95dB

Stereo: 2 channels of audio, usually designed as left and right

Supercardioid: narrower microphone polar pattern for better sound isolation

Transients: the sporadic higher levels in your program (from a percussion or guitar attack, for example) that can result in overload distortion if not properly compressed

TRS: stands for Tip, Ring, Sleeve. TRS is a balanced circuit that uses a phone plug-style connection with three conductors (the tip, the ring, and the sleeve) instead of just two (the tip and the sleeve)

Unbalanced: an audio circuit whose two conductors are unequal at ground, usually because one conductor operates as ground. An unbalanced audio circuit is more susceptible to noise problems than balanced circuits. Noise can be combated by keeping lines as short as possible

Unidirectional microphone: mics that are most sensitive to sources directly in front of them, minimizing off-axis sound and background noise

XLR: balanced, circular 3-pin connector typically used for microphone and line-level signals. Each pin is a separate channel, but pin 1 is always ground. The connection was developed by Cannon and is sometimes called a Cannon connector.