• Selecting the Right Loudspeakers for your Venue

  • By: Kevin Watson, CTS-D, CTS-I, AVL Engineer, Business Development
    The number of loudspeakers available is probably equal to the number of frog species in the world. There are thousands to choose from at various sizes, shapes, and types. If you’re looking for a loudspeaker solution and your heads a little dizzy from the choices, I’ll break down some of the different types, their uses, and why as designers we use special tools to make sure we get the correct one.

    Passive vs. Active Boxes

    Let’s first break it down between what are called passive and active boxes. These can really be any size or shape, but a passive box means that it needs an external amplifier. A passive loudspeaker generally just has the speaker drivers in the cabinet along with some internal processing like crossovers. On the flip side, an active loudspeaker contains an amplifier within the cabinet and therefore it actively amplifies it all as one unit.

    There are some manufacturers who only make active boxes and a lot of manufacturers who make both active and passive boxes. Active loudspeaker systems can be efficient due to the fact that the amplifier inside is sized for the drivers, taking the guesswork out of finding the right amplifier or having the more power than needed.  I have found that in some venues, the downside of active boxes is that if the electronics go bad you have to go back up in the air to fix it. You also need to remember to run power to these locations, so make sure to coordinate that.

    Point Source & Line Array

    Two other commonly used terms in the loudspeaker world are point source and line array. A point source loudspeaker cabinet is generally a speaker that is hung by itself, therefore a single source creating a point for which the sound comes from.  Alternately, a line array loudspeaker system are multiple speakers that are generally hung vertically with each other.  The cabinets work together to obtain greater volume and varying coverage patterns. 

    Line Array – D&B Audio
    Point Source – Fulcrum Acoustic

    Point source loudspeakers are used everywhere from clubs to conference rooms and from gymnasiums to auditoriums.  There are many different coverage patterns available which allow us to pick the best point source for the room.  Manufacturers are developing new cabinets that have tighter coverage patterns and louder each year.  However, when you combine multiple loudspeakers together and form a line array you can get a much higher output.  These systems are used for a high-energy Church productions, above average high school musicals, and professional sports stadiums. And let’s face it, looking at a 24-cabinet line array like at a U2 concert just seems awesome. 

    Column and Digitally Steerable Arrays

    The last two terms I’ll touch base on are column arrays and digitally steerable arrays. Column arrays differ from line arrays in that they’re tall and skinny speaker cabinets made up of numerous smaller drivers. These are generally intended for voice applications but some provide low frequency production for music. Column array speakers thrive in highly reverberant spaces because they help with keeping the sound shooting outward instead of upward and into reverberant areas. Places like airports, gymnasiums and cathedral churches are great places for column arrays.

    Column Array – JBL
    Digitally Steerable – Renkus-Heinz

    The fancy version of a column array speaker is the digitally steerable array. These have electronics and amplifiers built in.  Using digital processing we can steer the sound towards the audiences.  Some advanced loudspeakers even allow multiple lobes which allow you to aim towards the front, the back, or even a balcony separately. These types of speakers cost more since they have processing and amplification for each driver but they can perform really well in a large reverberant space that otherwise would be unintelligible.

    Making the Right Decision

    Since there are so many different types, output levels, and sizes of loudspeakers, we as designers use computer software to help us select the most appropriate one.  EASE is a 3D computer modeling software where we input the room’s dimensions and assign materials to wall surfaces to create a model of the room.  Then using data that the manufacturers provide, we insert their loudspeaker and see how it covers the audience areas and what its volume levels are.  We can look at this from a 2D and 3D perspective which provides the best representation for how the loudspeaker will perform without actually being in the space.

    If you’re struggling to figure out what type of loudspeaker is best for your venue ESCO would be happy to help you find an appropriate solution…and now you’ll know what we’re talking about!

    Kevin Watson is currently an AVL-Engineer for ESCO Communications and brings 13 years of experience in AV system design and acoustics. His certifications include a CTS-D and CTS-I from Avixa (new name for InfoComm International) and an EIT (Engineer in Training) by National Council of Examiners for Engineering and Surveying (NCEES).