What is a Tap Setting?
A tap setting is simple a dial or a screw that you turn, either on the front or the back of the speaker to select the wattage for your speaker.
When you have a distributed speaker system (also known as a 100 or 70 Volt) – which are most commonly used where mulitple speakers are required such as airports, shopping centers, schools and sports arenas – each speaker must be connected to a transformer which has a selection of input taps. Input taps are used to select the relative amount of wattage the transformer should pass onto the speaker based on its application. Smaller, lower noise areas may only need 5 watts, while larger and louder areas may need 20. The “tap” is used to select that wattage.
Unlike in traditional 8-ohm audio, a 120-watt 70-volt mixer/amplifier does not pass on exactly 120-watts of audio to a speaker. Instead, it only passes as much wattage as is determined by which wattage you select for the transformer to pass to the speaker. You can literally crank up the mixer as loud as it will go (although I would not recommend this as it could potentially cause damage to your system) but no more than the tap setting wattage will pass to the speaker. This wattage is normally color-coded to help make your selection.
As you can imagine, leaving these open wires hanging free or non-terminated can be potentially dangerous. As a result, many manufacturers found it simpler and more practical to incorporate a dial to choose your tap settings for the speaker rather than hooking it up to a yellow wire, blue wire, etc.
How to Use Tap Settings
How do you know what wattage to choose on a tap dial?
Your knee-jerk reaction may be to turn up the wattage as high as possible to allow the most audio to pass through the speaker. Depending on your application, we may not want to do that.
A classic example of this would be a small retail store. A 750-1,000 square foot retail store with a 10’ ceilings may only require 6 speakers (depending on the space and the audio needs) for light background music, but we will need to find a mixer/amplifier to go along with them. I would recommend in this case going with a 70-volt system to allow you to bypass any complicated low impedance calculations while also giving you the ability to expand a system, if desired. A 60-watt amplifier would allow you to tap the speakers up to their highest setting below 10-watts, as we always want to leave headroom on an amplifier – regardless of 70-volt or 8-ohm.That means we don’t want the sum of our speakers to equal exactly what the amplifier will power, as that may cause problems down the road with the amplifier working harder than it should.
What tap settings do you choose?
This depends on the speaker and what taps its transformer would allow. We could tap these speakers at a 7.5-watt tap if one is available, but that very well may be too much for your application. Commercial speakers are incredibly efficient and many times capable of volumes over 85 decibels at 1-watt at 1 meter. Likely, 85 decibels is louder than you’d prefer to listen to your television at home and hardly what you want to listen to while shopping.
When you start getting into a much louder volume you actually lose control of the system to an extent. Too high of a tap setting means you cannot turn the system up or down from the amplifier as precisely as you may want. A “master” volume knob at the 9 o-clock position may be entirely too loud at a 7.5-watt setting, whereas a 3 o-clock position at the 2.5-watt setting may be ideal. Now, what happens if your new cashier bumps the volume knob all the way up and you are using the 7.5-watt tap? Likely, your speakers will be fine, but your customers may be a different story.
In the end, it’s probably best to give us a call and we can walk you through the setting you need for your particular system and results.