Selecting A Sound

Each of these questions is important and must be answered in advance. So, there's a lot of work to be done before you can zero in on the type of device best suited to handle your specific application.

When an equipment manufacturer decides that an audible alarm device is required in a product and contacts the alarm manufacturer, a number of criteria should be considered prior to beginning the electrical and mechanical design:

• What type of product is the alarm device to be used in and who is the audience that will be impacted? Will the application be consumer, industrial, emergency, etc., and who will use it?Nailing down all the facts in advance will help determine what sort of sounds should be considered.

• Should the tone be continuous or intermittent? Intermittent tones are generally more discernible than continuous tones.

• What is the magnitude of sound required to perform the expected task? Most devices are available in loud, medium, or soft sounds. The sound level selected should match the application and the surrounding environment. Care should be taken to make certain the device's tone doesn't melt into the background noise and not be heard.

• Will the product be operating under emergency conditions? If the product is responsible for signifying an emergency, you will probably want it to emit a loud, very discernible, audible alarm.

• What type of actuation signal will be available? Audible alarms must be supplied with an actuating signal. However, most manufacturers of various types of audible alarms can supply devices which are actuated by anything from low voltage DC signals to AC voltages up to 250 VAC.

• Does the immediate environment present any constraints as far as the type of sound orsound level is concerned? Will the sound present an annoyance or impair the work of people or equipment in close proximity to the device?

• Will other alarm devices be operating in close proximity? Consideration should be given to ensure that the tone the device is generating doesn't get confused with other devices. An example of this problem occurring is in hospitals where other alarm devices that produce similar sounds could well be in close proximity.