Taking care of the technical production for a live show requires a fair amount of training and the knowledge of each piece of equipment involved. There can be a bit of confusion when it comes to two components of the sound system at these events, speakers and monitors. It’s good to get a grasp on the basics behind both of these pieces of equipment and how they figure into the setup for live shows.
A Basic Look at Speakers
For live shows to be a memorable and enjoyable experience, the speakers that will be used need to be of top quality and set up properly. They actually represent the end point of the sound system that will be at the venue when it comes to signal flow, but they’ll sometimes be the first thing that can let you know that something is off with the sound during a performance.
There are two basic types of speakers in this case, active and passive. Active speakers are powered, usually by a power amplifier that’s built into the unit. A tech can plug the IEC (International Electrotechnical Commission) cables in to turn them on. Passive speakers don’t have their own power and so they need an external power amp to be operated. Portable sound systems rely on active speakers more, and larger setups will go with passive speakers.
The Basics of Monitors
First of all, an audio engineer will find that monitors are also speakers. However, a monitor differs from other speakers in a very critical way. In contrast from normal speakers, monitors are on stage and benefits the performers and audio technicians.
Additionally, there are two types of speakers: active and passive types.The passive ones have a loudspeaker and a horn inside of a cabinet housing. These also have to be plugged into an external power amp. Active monitors have the loudspeaker and horn in the cabinet housing along with a power amp. They are equipped to have the signal from the mixing board plugged right in. Without monitors, performers would pick up the sound in reverberated reflections which can be distorted.
The Process of Setting Up the Speakers
Now that there’s some clarity about speakers and monitors, the next step is to detail how they will each be set up for live shows. This is dependent on the type of venue that the show will be held at, because the physical environment of the stage and surroundings will help determine which types of each the sound crew will need to set up. Larger venues will mean that the sound will fade away once the distance from the speakers increases. Smaller spaces pose less of an issue in that regard.
To set the speakers up, the sound technician should look at the distance from where the speaker will be to where the farthest person from the stage is likely to be. Calculating this distance will help to determine the amount of signal loss.
The standards for each type of performance venue listed are measured in meters:
- Cafes, bars and restaurants – 5m to 10m
- Small outdoor events, churches, nightclubs – 10m to 30m
- Stadiums, concert halls, outdoor festivals and parties – beyond 30m
The next step is to determine the efficiency rating for the speakers that will be in use at the venue. Every speaker has an efficiency rating which denotes how well it can convert the audio from the amplifiers into sound. Smaller speakers tend to have a lower efficiency rating than larger ones, and larger speakers will be the go-to for most places.
Passive Speakers and Power Amplifiers
To that end, passive speakers will be in use for performances in larger venues with associated power amplifiers. Members of the sound crew will select the right power amps to go with these speakers based on the peak power and impedance for both pieces of equipment. Impedance refers to the amount of root mean square (RMS) continuous power handling, which is measured in ohms. If the speakers operate at lower impedance than the amps, the amps will put more impedance out which can damage the speakers. If the speakers are more powerful than the amps in terms of impedance, the system will be weakened.
What is Peak Power?
Peak power refers to the amount of wattage that the system speaker can handle on a continuous basis in a safe manner. If the speaker has too much peak power that gets fed into the amplifier, a sound tech can use a limiter to reduce it. The limiter is placed at the input of each power amplifier in use and has control dials that help to reduce that power and regulate it during a performance.
Determining a Speaker Setup
Once that’s determined, the speakers should be arranged on either side of the stage area and aimed at the crowd. Their respective amplifiers should be along side them with plenty of room in the middle of the stage for the performers and their microphones. For larger events, these speakers can be stacked on top of each other or suspended in an array format for wider crowd coverage.
Setting Up the Monitors
The monitor speakers tend to be arranged towards the end of sound equipment setups. One will be placed at the front of the central stage area, with another behind where the performers will be. Multiple performers will require multiple monitors to be set up. This is partially so that the performers can hear themselves, but it’s also so that the front-of-house (FOH) audio techs can set up their mix properly. Each of the monitors in use will be connected in similar fashion to how the main speakers are connected in addition to being connected to a graphic equalizer and an auxiliary send that goes into the mixing console.
Prepping for the Show
Once the physical setup is complete, the sound technicians will get to work on having everything in order with each of the levels of the monitors and the main speakers. When it comes to levels, monitors are usually unrestricted. If not checked and calibrated, their volume will bleed off the stage and sound bad as a result. The goal is to get the levels of every monitor in use to a point where the performers can hear what they’re doing clearly. Then this audio can be compared to what the FOH mixing console will have once they get their levels set.
The audio engineer in charge of the mixing console will do some equalizing on the various channels until they hit upon the sound that they want from the front-of-house. Techs will check on how the audio from the monitors sound by walking into the audience area during a sound check with the performers. If they hear the audio more pronounced as they get past the third row of audience seating, it’s advised to turn those monitor levels down. This sort of testing is a key part of the sound checks and rehearsals taking place before the show is set to begin.
Even with everything laid out, there are issues that can arise with the setup of the monitors and the main speakers. This process takes place in the hours before a show begins, and that can add extra pressure on those working to ensure everything goes well for the performers. These issues usually are loose cables, equipment plugged into the wrong output or inadvertently covering aeration vents that are part of the equipment. A precise walkthrough of the entire setup will usually eliminate these issues. Of course, the crew will keep a close watch to make sure that the speakers and monitors and their respective amps don’t undergo too much stress that can come from unexpected rises in impedance as mentioned before.
The speakers and monitors are significant components of the sound system at a live venue. These pieces of equipment can be shrouded in a bit of confusion. But all it takes to clear that up is to gain a better idea of how each of them operates and where they fit in within the setup of a sound system. Knowing this information also allows one to have a greater appreciation of the professionals who make their living putting these systems together.
Want to Learn More?
No event or convention is complete without speakers and monitors, and it takes a skilled live sound technician to get the job done. The process to provide these results is one that entails a lot of hard work & improvisation. If this kind of creativity appeals to you & you’re curious enough to learn more, take a moment to check out IPR’s Live Sound & Show Production Program and the training that they provide on-site about the tools needed to succeed.
Contact us today to learn more about the live sound and show production program and starting a rewarding career in the audio industry.