A subwoofer is a loudspeaker designed to produce low-pitched sounds. The term “subwoofer” is used in two different ways. It can refer to a part of a stereo or home theater system, which includes the woofer and tweeter speakers, or it can refer to a speaker that produces low frequencies, typically for use with a PA system.
The rotary subwoofer playing music is a type of speaker that has a circular shape. It is typically used in car audio systems, but can also be found in home theater setups.
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Subwoofers can generate sound frequencies below 30 Hz, however humans have difficulty hearing frequencies below 20 Hz. This is why many subwoofer manufacturers include frequency response ranges of 20 to 200 Hz on their products.
Researchers found that increasing the sound pressure level (SPL) may assist people hear frequencies fewer than 20 Hz in the early 1970s, and rotating subwoofers were created for this reason.
We’ll go over what rotary subwoofers are, what they’re used for, and how they function in this post.
A Rotary Subwoofer is a kind of subwoofer that rotates.
A rotary subwoofer, sometimes known as a propeller subwoofer, works similarly to a typical subwoofer, except it alters the pitch of a propeller spinning at a constant speed using the motion of a traditional speaker-voice coil. The audio signal from the voice coil regulates the pitch of the fan blades, ensuring that the subwoofer reproduces very low sound frequencies. These sophisticated subwoofers have the ability to compress the air in a sealed space and generate sound frequencies as low as 0 Hz.
What Are Rotary Subwoofers and How Do They Work?
A rotating subwoofer can generate extremely low sound frequencies thanks to air woofer technology. Furthermore, it enables the amp to use less energy while still providing a superb music experience.
Because of the various functioning mechanisms of these distinct kinds of subs, the amp uses less energy than a conventional subwoofer.
Because the amplifier is simply altering the pitch of the blades, the rotating woofer will need much less power per dB of sound produced than a traditional subwoofer.
Remember that the input signal for a traditional subwoofer must drive the voice coil inside a magnetic field, which drives the cone to displace air and create sound. This requires greater effort.
Here’s a closer look at how a rotary or propeller subwoofer works.
The incoming signal to the voice coil, for starters, alters the pitch of the fan blades while it rotates at a steady speed, usually between 600 and 800 RPM. To elaborate, the incoming signal alters the pitch of the blades in accordance with the waveform of the signal.
Because the fan may swing both positive and negative in relation to a zero pitch spinning blade position, this is possible. As a result, it may represent the waveform of an incoming signal.
Humans may be affected by the produced sound pressure waves. We can sense them as well.
The rotary does not make a sound if there is no signal. Because the blades spin at zero pitch, this occurs.
The audio amp’s only purpose is to alter the pitch of the blades. The spinning, on the other hand, generates an acoustic sound wave that travels forward and backward from the blades.
When the blade pitch changes in a good way, the sound wave that results has a good chance of being good, and vice versa.
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How air woofer technology guarantees accurate low-frequency reproduction
Rotary subwoofers are more energy efficient than conventional subwoofers. The effectiveness of a typical cone diaphragm decreases when the sound frequency falls below 20 Hz.
Consider what happens if the frequency of a traditional subwoofer is cut in half. To generate the same sound amplitude, the diaphragm must displace at least four times the amount of air. This implies that traditional cone diaphragms need a lot of energy to reproduce the low frequencies needed.
A rotating subwoofer’s acoustic impedance, on the other hand, is always precisely suited to the surrounding environment.
As a result, it can replicate much smaller quantities of frequency at very high levels. This allows them to reproduce extremely low frequencies more effectively than cone-based subwoofers.
For a better understanding, let’s go through it again. Imagine what would happen if the frequency was cut in half. The blades in this instance spin twice as fast each cycle. As a result, the diaphragm’s surface area is doubled by the blades. In most listening spaces, this may result in a reasonably flat frequency response down to one Hz.
Because rotating subwoofers may generate the lowest frequency, you’ll need to test the degree of efficiency using scientific equipment. A dB meter, for example, might be used.
Because no human ear can detect noises so low, this is required. Remember that when the frequency approaches zero, the effectiveness of a rotating subwoofer will decrease.
To put it another way, the sub’s “vibrations” are quite likely to be generated in a manner that was not intended. The good news is that large-diameter rotating subwoofers are capable of producing the lowest tones effectively.
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How can air woofer technology guarantee that low-frequency sound production has a low power cost?
The acoustic impedance of rotating subwoofers is precisely matched. As a result, the rotating subwoofer uses less amplifier power to produce the same sound as a traditional subwoofer.
If a rotating sub needs 100 watts to reproduce excellent sound at 20 Hz, a conventional sub may need up to 500 watts to provide the same output at the same frequency.
If the high power consumption of the subwoofer concerns you, a rotating subwoofer may provide the cinematic experience you want at a lower cost.
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The use of air woofer technology reduces distortions.
Rotating subwoofers, as we’ve seen, are intended to reproduce frequencies below 20 Hz. This demonstrates how distortion may grow when the input frequency surpasses the fan’s spin rate.
The fan can spin at about 1,200 RPM at 20 Hz. Current versions utilize AC induction motors that spin at about 800 RPM, which reduces distortion (13 Hz). Furthermore, once fitted, the subwoofers are meticulously braced to ensure that the blades are aligned with the circular apertures.
The subwoofer’s unusual construction allows it to transfer air between exterior chambers and produce sound pressure from both its back and front-ends without canceling each other.
That may not be enough to ensure that the product is appropriate for the intended use. Without a sure, the price seems to be excessive. The payoff, on the other hand, is well worth the investment. A manifold chamber is also required in front of the device.
The noise generated by the spinning blades is effectively muted by the chamber. The sound quality may increase considerably if the blades are positioned in a circular cutout, particularly if they have the appropriate back-wave chamber.
The effective radiating regions of rotating subwoofers are enormous. This is also why we need massive back-wave chambers. To obtain the greatest audio experience, you’ll usually need a whole room, basement, or attic.
If you meet all of the criteria, a rotating subwoofer should be able to produce 95db SPL from 20 Hz to below 1 Hz, which is an extremely low sound frequency. Is it, however, detectable by the human ear?
Yes, we can hear the sound, according to listening tests conducted by different specialists, including Bruce Thigpen, the inventor of the Thigpen Rotary Subwoofer Model 17. However, high SPLs are required. Rotary subwoofers are the answer. Because of this, rotating subwoofers are classified as SPL subwoofers. You may learn more about what an SPL subwoofer is by reading this article.
Conclusion
As we’ve seen, new research has debunked the myth that people can only hear frequencies of 20 Hz and higher.
Lower frequencies, on the other hand, are considerably less sensitive to human ears, requiring greater sound pressure levels to detect them. Because moving conventional subwoofer cones are incapable of producing these low frequencies, rotating subwoofers are suitable for this application.
A rotary subwoofer is a type of loudspeaker that uses a rotating cone to move air. It is found in many types of sound systems including car audio, home theater, and professional audio. Reference: rotary subwoofer diy.
Frequently Asked Questions
What is the most powerful subwoofer?
The most powerful subwoofer is the JL Audio 12W1v3-4.
What does the sub in subwoofer mean?
The subwoofer is a speaker that provides bass frequencies.
What is the most expensive subwoofer?
The most expensive subwoofer is the JL Audio Fathom F112D2.
