Why Does Doubling Speakers Double Sound Pressure with Less Power?

In summary: B SPL.So, the conclusion I reached is this: If you want to achieve + 6 dB SPL, you need to quadruple the power.
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One post covered it well, 2 identical speakers in parallel driven from the same voltage will give you 6dB gain, 3 db from the double power, 3 db from the doubled cone/radiating area. 2 identical speakers regardless of connection, series or parallel will give you a gain of 3dB when driven the with same power. This gain comes from an efficiency increase due to the larger coupling area of the two cones.

Consider a speaker, when the cone moves it displaces a volume of air, but the mass of that air is a tiny portion of the mass the linear motor in the speaker has to move, which is the cone itself. So the motor power is being mostly used to move itself.

A good way to look at a speaker is an impedance matching problem. Most of the energy being put into the speaker in free air is used to move the cone. If we could come up with some sort of "air impedance matching transformer", so that we could increase the proportional amount of air mass the speaker moves relative to the cone mass, then you get a massive gain in efficiency. Doubling the cone area gives that increase in radiating efficiency, but also doubles the mass of the cones.

Enter the horn. This is an "air impedance matching transformer", now the speaker is able to use the electrical energy to more efficiently move air by matching the high pressure low displacement volume capability of the motor assembly to the large volume displacement low pressure mouth, voila way more noise.
 
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<h2>1. Why does doubling the number of speakers result in a higher sound pressure?</h2><p>When sound waves are produced by a speaker, they spread out in all directions. This means that the sound energy is distributed over a larger area, resulting in a lower sound pressure. However, when you double the number of speakers, the sound waves from each speaker overlap and combine, resulting in a higher sound pressure at a specific location.</p><h2>2. How does doubling speakers result in less power being used?</h2><p>When you double the number of speakers, each speaker does not need to work as hard to produce the same sound level. This is because the sound waves from each speaker combine and reinforce each other, resulting in a more efficient use of power. Therefore, less power is needed to achieve the same sound pressure as a single speaker.</p><h2>3. Is there a limit to how many speakers can be doubled before there is no change in sound pressure?</h2><p>Yes, there is a limit to how many speakers can be doubled before there is no significant change in sound pressure. This is because at a certain point, the sound waves from the speakers will start to cancel each other out, resulting in a decrease in sound pressure. The exact number of speakers that can be doubled before this happens will depend on various factors such as the size and layout of the room.</p><h2>4. Does doubling speakers always result in a better sound quality?</h2><p>No, doubling speakers does not always result in a better sound quality. While it may increase the sound pressure, it can also lead to distortion and uneven sound distribution if the speakers are not properly placed and calibrated. Additionally, the quality of the speakers themselves also plays a significant role in the overall sound quality.</p><h2>5. Can doubling speakers be used as a substitute for increasing the volume?</h2><p>Yes, doubling speakers can be used as a substitute for increasing the volume to some extent. However, it is important to note that doubling speakers does not necessarily mean doubling the volume. Additionally, as mentioned before, doubling speakers can also lead to distortion and uneven sound distribution, so it may not always be the most effective solution for increasing volume.</p>

Related to Why Does Doubling Speakers Double Sound Pressure with Less Power?

1. Why does doubling the number of speakers result in a higher sound pressure?

When sound waves are produced by a speaker, they spread out in all directions. This means that the sound energy is distributed over a larger area, resulting in a lower sound pressure. However, when you double the number of speakers, the sound waves from each speaker overlap and combine, resulting in a higher sound pressure at a specific location.

2. How does doubling speakers result in less power being used?

When you double the number of speakers, each speaker does not need to work as hard to produce the same sound level. This is because the sound waves from each speaker combine and reinforce each other, resulting in a more efficient use of power. Therefore, less power is needed to achieve the same sound pressure as a single speaker.

3. Is there a limit to how many speakers can be doubled before there is no change in sound pressure?

Yes, there is a limit to how many speakers can be doubled before there is no significant change in sound pressure. This is because at a certain point, the sound waves from the speakers will start to cancel each other out, resulting in a decrease in sound pressure. The exact number of speakers that can be doubled before this happens will depend on various factors such as the size and layout of the room.

4. Does doubling speakers always result in a better sound quality?

No, doubling speakers does not always result in a better sound quality. While it may increase the sound pressure, it can also lead to distortion and uneven sound distribution if the speakers are not properly placed and calibrated. Additionally, the quality of the speakers themselves also plays a significant role in the overall sound quality.

5. Can doubling speakers be used as a substitute for increasing the volume?

Yes, doubling speakers can be used as a substitute for increasing the volume to some extent. However, it is important to note that doubling speakers does not necessarily mean doubling the volume. Additionally, as mentioned before, doubling speakers can also lead to distortion and uneven sound distribution, so it may not always be the most effective solution for increasing volume.

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