Experienced musicians know a great deal of preparation goes into a successful performance. They also know a key to an ensemble’s success is its ability to travel around and reach new audiences. Like a frame around a great painting, a music ensemble needs the right sound system to ensure that its performance yields the desired “sonic impact.” Picking the best portable public address (PA) system for an ensemble depends on music style, performance needs, and of course, the venue.
PA systems amplify sound for a live performance, providing what is called sound reinforcement. With a few added components they can also be used to record. A typical PA system contains a mixer to handle inputs and processing, an amplification system to strengthen the overall volume of the ensemble’s sound, and a delivery system made up of speakers. Let’s take a look at the process of sound reinforcement, what tools are needed, and a few different products available for the traveling ensemble.
Cathrine Savino and John Coggiola are researchers at the Setnor School of Music’s Center for Live Music in the 21st Century.
Capturing Your Sound
Microphones are the first core components needed for sound reinforcement. Usually purchased separately from a PA system, two types of microphones—dynamic or condenser—are typically used.
Dynamic microphones are constructed with more rugged coil diaphragms. This construction is less expensive to manufacture and creates a more durable tool, well-suited for use on the road. Although practically priced, dynamic microphones provide good quality with regard to frequency response and signal sensitivity. Condenser microphones feature fragile metal-plated diaphragms designed to capture the desired sound vibrations. This design is more expensive to manufacture but they have greater frequency response and signal sensitivity. Condenser microphones require an additional power source (phantom power) to operate, which is a standard feature on most mixers. These mics are essential for recording soft instruments like unamplified acoustic guitar, but are not typically handheld by performers for sound reinforcement.
Processing Your Sound
Mixing consoles (often simply called mixers) combine audio signals from multiple instruments and microphones and allow users to change aspects of the various input signals before converting them to the desired output signals. A mixer is a primary component in an all-in-one PA system. All-in-one PA systems have amplifiers built into the mixer console. This increases portability, but restricts the amount of power the system can handle. All mixers have multiple input channels, by which users control volume and frequency equalization. There are a variety of other controls a mixer may offer in its design, such as volume controls for multiple monitors, headphones, and special effects like reverberation and digital delay to enhance the sound signals.
To select a PA system and mixer the performer should consider his or her desired result, including the music style (acoustic or electric) and setting of the ensemble.
The number of performers will determine the number of channels required. Determine who needs amplification and how they will connect to the mixer. Standard connection types are XLR and quarter-inch plugs or jacks. XLR is a common microphone connection transmitting a signal with either line-level or phantom power. Quarter-inch plugs or jacks are exclusively instrument connections transmitting their signals at line-level. Each mixer has a different configuration of inputs.
When signals reach the PA mixer it allows for varying degrees of control over each sound source channel. Most all-in-one PAs have two EQ controls, but larger mixers may have three or more, including other types of effects processing like reverberation and delay.
Will the performers be able to hear themselves perform within the acoustics of the venue? If not, they will need a monitor speaker option from the mixer to send sound back towards them. These are just a few of the details to consider when deciding on the right PA system for a performance.
Delivering Your Sound
The final step in reinforcing an ensemble’s performance is sending the master signals to the PA system speakers. Many all-in-one PA systems include multiple speakers with cables to connect them to the mixer. The most common PA configuration of multi-purpose speakers is one front of house (FOH) and one monitor speaker. FOH speakers deliver sound to the audience while monitor speakers provide a less powerful sound reference for the performers.
If you need to purchase your own speakers for a PA system, consider the differences between powered and passive speakers. If portability is desired, powered speakers are recommended since they require no separate amplifiers. This approach also reduces the number of components, making assembling and tearing down the stage easier. If you already have amplification available, passive (unamplified) speakers allow for customization.
With a basic understanding of sound reinforcement, musicians can create a first-rate performance for their audience. Now that’s worth the price of admission!
All-in-one PA Systems
Portable PA systems usually are a combination of mixer, amplifier, speakers (with/without stands), and speaker cables. When choosing a PA system, keep in mind the size of the venue and style of music (acoustic vs. amplified instruments). These factors will dictate what size PA system is needed.
Alto Professional Mixpack Express PA system closes into one piece for easy transport. It features two 10-inch speakers and 350 watts of continuous power. Its built-in mixer has five input channels with 16 DSP presets with 24-bit effects, including reverb, delay, and chorus. The integrated seven-band graphic EQ allows you to fine-tune the performance, while you monitor it through its built-in LED and monitor out jack. Two speaker cables and one microphone cable are included. MSRP: $599
Behringer Europort EPA150 is a light-weight, ultra-portable PA system option for basic sound reinforcement. It includes a 150-Watt amplifier (75 x 2), limited inputs (five channels), phantom power, and a 24-bit effects processor. It includes three EQ controls per channel, two FOH speakers, microphone, and mic stand. Designed for intimate performance venues, there is no monitor. MSRP: $653