How To Choose The Right Commercial Amplifier and 70V Speaker Tap Settings For Your Audio System

Are you trying to sort out precisely what tap settings you need to use to ensure your 70V amplifier and commercial speakers work together correctly and deliver the desired volume? We have you covered. Below is our quick user guide to help you determine the correct 70V speaker tap settings for your audio system, including which amplifier will pair best with your speakers.

What Are 70V Speaker Transformer Tap Settings?

70-volt speakers have a built-in transformer that allows you to adjust their wattage. This dial is called a speaker "tap." You can set the tap to determine how loud the speaker can go. The higher the tap, the louder it can get; the lower the tap, the softer the volume will be.

Tap settings are critical when determining how much amplifier power you need for your speakers. When setting 70V speaker taps, the total sum of your speaker's combined wattage should be, at most, 80% of your amplifier's total available wattage output, leaving 20% headroom of buffer space. The purpose of headroom is to allow the amplifier to create the wattage needed to power all the speakers while accounting for variations in signal and protecting your equipment.

Here is a real-life example: Let's take our Pure Resonance Audio MA30BT commercial mixer amplifier, which is 30 watts, and our C3 70-volt ceiling speakers with 1.5, 3, and 5-watt tap settings. To stay within 80% of the amplifier's power, we'll want to use, at most, 24 watts. This means that if we tap the C3 at 5 watts, the maximum number of speakers we can use with this 70V amplifier is (4) speakers.

  • 5 watts x 4 speakers = 20 watts total

This is an ideal setting because it's less than our 24-watt maximum. If we went up to 5 speakers, we would exceed the 80% rule.

  • 5 watts x 5 speakers = 25 watts total

Now, if we take the same MA30BT 30-watt amplifier and C3 speakers but tap them at 3 watts, we could use up to (8) speakers total.

  • 3 watts x 8 speakers = 24 watts total (precisely 80% of the amplifier's capacity)

What is the Speaker Sensitivity Rating?

Now that you know precisely how much amplifier power you need, we can look at setting the appropriate volume levels. Every speaker has a sensitivity rating, which measures sound pressure from a given wattage at a certain distance. In the audio world, this is measured in decibels using 1 watt from a distance of 1 meter. In other words, speaker sensitivity refers to a speaker's ability to convert power into sound. Bottom line: speaker sensitivity determines how much power you need to make the speaker project the desired volume.

In addition, to correctly set your tap levels, you'll also need to understand decibels and what they mean. How much sound (decibels) does a given noise produce? We created a cheat sheet below.

dB (Decibel) Breakdown:

  • 30 dB = a whispering voice
  • 60 dB = normal talking voice
  • 90 dB = a lawn mower
  • 120 dB = a loud concert where you can barely hear your neighbor

Other key questions to ask before setting your tap levels:

  1. How high are your ceilings? The higher the ceilings, the higher your tap setting may need to be.
  2. In what kind of atmosphere are you using your speakers? A noisy restaurant or bar will need higher levels than a dentist's office or spa.
  3. What type of speakers do you have? The hardware you are using will affect these settings as well.

How to Calculate Your 70V Speaker Tap Settings

With all this in mind, we can now determine which 70V speaker tap setting is right for you. For our example scenario, say you have a restaurant with beautiful open ceilings and want to install our Pure Resonance Audio PD6 pendant commercial speakers for music. The ceiling is roughly 20 feet high, and you are hanging your PD6 5 feet from the ceiling, which is 15 feet from the floor. Now we need to convert that into meters. In round numbers, 3 feet is roughly 1 meter. So at 15 feet, your speakers hang about 5 meters off the ground. In a restaurant, people will be sitting down, meaning the listening level of someone sitting to the speaker is roughly 12 feet or 4 meters.

The PD6 has a sensitivity rating of 87 dB 1m/1w. When sound leaves a speaker, you lose 6 dB every time you double the distance away from the speaker. If we want to keep 87 dB sensitivity at our 4-meter listening level, we can flip the math and add 6 dB to find the dB we need to start with at 1 meter.

  • 4m: 87 dB
  • 4m to 2m: 87 dB + 6 dB = 93 dB
  • 2m to 1m: 93 dB + 6 dB = 99 dB

So, to get 87 dB at 4 meters, we need to start with 99 dB at 1 meter. Now, this is where adjusting your speaker tap settings comes in. Using the inverse square law, doubling the speaker's wattage from 1 to 2 watts increases the speaker's output by 3 dB. So, for a speaker with a sensitivity rating of 87 dB at 1 watt, you can calculate the following:

  • 1W: 87 dB
  • 1W to 2W: 87 dB + 3 dB = 90 dB
  • 2W to 4W: 90 dB + 3 dB = 93 dB
  • 4W to 8W: 93 dB + 3 dB = 96 dB
  • 8W to 16W: 96 dB + 3 dB = 99 dB

So in this example, the setting necessary to reach the targeted decibel output of 87 dB at 4 meters with our PD6 is the 16-watt tap setting. However, the PD6 can be tapped as high as 32 watts, and we recommend using a higher tap setting if your commercial amplifier can handle it. This way, you’ll have more volume range available.

You can also use the speaker tap setting as a form of volume control. You can change tap settings in different areas of your space. If you want the host area to be quieter than the rest of your restaurant, tap those speakers at 4 or 8 watts and the rest at 16 watts.

When adjusting your speaker transformer tap settings, remember that your 70-volt speakers' total combined wattage should be, at most, 80% of your amplifier's total wattage capability. Leaving this headroom on your 70V amplifier will ensure your sound system can perform its best without damaging it.

We know these calculations can get complicated, so if you have more questions about choosing the most suitable commercial amplifier or setting your 70V speaker tap settings, call us at (866) 676-7804 or email us at We're here to help!