Size is not everything!

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“Wow look at that speaker! We’re not a nightclub!!!”

I have heard this and similar comments time and again when designing a sound

system for a client for the first time.  A regular misconception is that the physical

size of a speaker is directly proportional to the volume or loudness of the sound

system, but that is generally not the case.

It’s true that you will need larger speakers to produce sound for a live concert

than you would need to install in a restaurant, but as sound gets quieter, there

is a minimum speaker size that you will reach, after which you start

compromising on sound quality.

Sound reproduction is all about moving air particles or vibrations.  In a

loudspeaker an electromagnet is attached to a cone which amplifies these

vibrations as it moves forwards and backwards, making sound waves in the

surrounding air and pumping them towards your ears.

So how do we hear music which is made up of lots of different sounds? Without

going too deeply into the science behind this, the frequency of the vibrations

(the number of sound waves that go past a fixed point say every second)

governs the pitch of the sound produced.  To faithfully reproduce all the

different frequencies of sound in a piece of music, good quality speakers use

different sized cones dedicated to high, medium and low frequencies, hence

the need for a minimum sized speaker to accommodate these. Generally in

each speaker cabinet there will be a bass driver (for low frequency sound

waves) and tweeter (for high frequency sound waves) and these will ensure

that sound from all frequencies is covered.

High frequency sound waves generate small movements of a small loudspeaker

surface area (the smaller tweeter cone) and lower frequency sound generate

large movements of a large surface area (the larger bass driver cone).  Basically

the lower the pitch of the sounds you want to replicate, the larger the surface

area of the cone and the larger the cubic volume of the speaker box you will need.

Sound volume (measured in decibels) is actually down to the amplitude of the

sound waves.  The amplitude of a sound wave (or the maximum distance moved),

is a reflection of how much energy it carries, the more energy it has the more air

particles that are moved for longer and the greater the sound we hear.

So, if you want a warm and full sound system throughout all the areas of your

venue, then you will need to have enough surface area of loudspeakers to excite

the air in the space and enough cubic volume of speaker cabinets to enable a

warm and comfortable sound to be generated in all areas.  This will be delivered

through a combination of; the right number of speakers of the right size installed

in the right locations.

Here at CGA Integration we generally use the smallest speaker cabinet required

to deliver a good full range sound in the required space, often in many multiples

to ensure that the distance from the customer to the speakers remains as

constant as possible as they move around the space.  This is explained in

"why so many speakers?!" on the CGA Blog.

Here you will find lots of articles dealing with speaker solutions including

“design led sound solutions” where we explain how to minimise the visual impact

of speakers whilst still generating superior sound & “speaker location; a sound delivery”

which considers the different types of speakers available and where they can be

installed for maximum audio effect.

To sum everything up, if speakers are too small or too few are used, this can

lead to issues in sound reproduction and quality, which will affect the

ambience of your venue.  Just remember, your AV design is created that way

or a reason, as “you cannot change the laws of physics!”