Matching a Sound System to Application

matchingasystem

Matching a Sound System, another article from Paul Johansen.

Once a client has made the initial approach, the sound company is faced with the job of making sure the equipment they supply is correct for the purpose intended. This often requires a site visit with the client present at the meeting to discuss the presentation of the event in question.

Sound systems come in an almost infinite combination of sizes and equipment variations. To the client this usually does not matter much because all he really wants is for the job to be done correctly with hope he won’t need to field any complaints from the audience about audibility or sound quality.

On the other hand the sound company does not want to do a whole lot of work he doesn’t need to do or put up a bigger system than is required.

The site visit should enable the audio contractor to make an accurate assessment of the size of the area to be covered by the audio system and the type of application the system is going into.

If there is a stage involved he will have or at least should have made a decision as to where it is going and have a good idea of the listening area he requires to be covered with legible sound.

The sound contract will examine the “line of site” across the covered area and work out how to set-up the loudspeakers in order to get adequate coverage. To achieve this he will need to know if there are any marquis or building structures of any kind that are going to interfere with the site lines involved.

He would normally first want to establish the kind of music or entertainment acts that are going to be using the system, along with the level of impact the client requires. This information will help him determine the basic configuration of the main stage speaker system. Once the main system has been discussed and decided upon, the discussion would normally move on as to whether or not any further remote reinforcement was in fact needed to push the sound further back or cover an area outside the reaches of the main stage system.

These remote systems are often referred to a delays or delay stacks. In the case of a fair ground or non musically focused event the delay system is often nothing more than a collection of what are often called “tin horns” or stand speakers as all they usually need to do, is provide announcement sound for the event commentators.

In the case of a high impact Rock concert, the delay speakers must provide perfectly time aligned music reproduction for audience members who have to be seated too far back from the stage to be in the coverage area of the main sound system.

A time alignment device (or delay line) must be used to achieve this correctly or the music will have a continual echo sound that badly compromises the music quality and can in fact destroy the entire performance.

What the delay unit does is to store the original sound in memory before sending it to the delay speakers, having slowing it down by the speed of sound divided by the distance, so that when it arrives at the delay system it is in perfect sync with the original music. If done properly it is impossible to tell whether the sound one is hearing, has come from the main speakers or the delay speakers.

 

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