Have you ever used audio devices that only utilize one speaker? Just walk down the aisle of the Hi-Fi section of a department store, and you can see plenty of “single-driver” sound systems. If you are wondering about the uniqueness of these speakers, then you should read on, as today we will find out what is a Full Range speaker all about!
At first glance, these types of audio equipment may not look very complicated at all. Not that they should be incredibly complex, but there is definitely much more to these speakers than meets the eye. In this article, we will be learning more about the fundamental design principles that sets full range speakers apart from the rest. Let’s begin learning!
Full Range Speakers – All in One Solution?
A speaker driver that is designed to reproduce as much of the audible frequency range as possible, is called a full-range loudspeaker. The performance of a full range speaker is limited by the physical constraints of a specific design. In most cases, the frequency range of these drivers are maximized by implementing a whizzer cone and other methods.
However, it is important to take note that most single driver systems (such as those in radios, or small computer speaker designs) are incapable of reproducing the entire audible frequency range (20 Hz – 20 kHz).
Here are the topics we will be looking into:
- Common designs
- Commercial applications
The design of a full-range driver is the same as any other dynamic drivers, except that the “cone” is optimized for better high-frequency performance. For instance, a small low-mass horn or whizzer cone can be mounted where the voice coil and diaphragm meet, which increases high-frequency output. The cone and whizzer are also made of materials that are optimized.
Some designs uses a radiating dome, which is acoustically active, instead of the typical dust-cap. The vast majority of speaker drivers have dust-caps that are intentionally constructed to be relatively acoustically inactive. You may sometimes find dust-caps that are designed to resemble a small conical shape, which are said to improve dispersion at higher frequencies.
Although a full-range driver is meant to effectively reproduce low and high frequencies (which is impossible due to physical limitations), in actuality, it is often limited to covering the audio spectrum from 100Hz onwards. The lower frequencies are usually left to be handled by a separate sub woofer, or by a special cabinet designed for low frequency reproduction.
In order for a full-range driver to meet its requirements, it must have good sensitivity (for lower frequencies) with a light voice coil (for high frequencies). Furthermore, these speakers often employ larger or stronger magnets than usual, in order to improve sensitivity, which in turn reduces the power needed at low frequencies as well as allowing a lighter voice coil.
In addition, the speaker enclosure also affects the overall performance. Many full range drivers have limited maximum excursions, thus requiring special enclosures that are capable of reasonable low end output, without the need for large excursions at low frequencies. Enclosures vary from cheap beige plastic boxes to expensive, large horn loaded enclosures.
You will often find full-range driver units being used in commercial, consumer-oriented sound systems, which may use a number of 200 mm (8″) full-range drivers, mounted into suspended ceilings or small ‘back-box’ enclosures. These systems are usually used for background music and announcements to visitors in retail stores, and public spaces.
It is actually more accurate to call these speakers ‘wide-range’ drivers, since their frequency response rarely extend to the extremes of the frequency range. There are manufacturers that produce small (typically 115 mm, or 4.5″) diameter full-range drivers, mounted into miniature enclosures, to be integrated with commercial sound systems that uses long speaker cables.
You can sometimes find full-range speaker systems that are designed with limited-range drivers. These speakers must be used with equalizers, in order to extend their frequency response. There are also full-range drivers that can achieve acceptable response without any signal processing. Full-range speaker systems may use single drivers that reach up to 15″ in size.
Sceptics often criticize full range drivers for their inability to reproduce frequencies at similar amplitudes, resulting in an inaccurate reproduction of the original audio signal. When multiple frequencies are produced by the same diaphragm, intermodulation distortion occurs, due to the fact that a single surface is trying to reproduce both frequencies simultaneously.
The audible impact of intermodulation distortion is not clearly established. The result is a degree of “frequency mixing”, but at a relatively low level. It may cause a full range driver to have reduced output at both ends of its frequency range, or its frequency response may be further reduced, ultimately compromising the sound system’s overall fidelity.
Supporters of full-range speakers claim superior phase coherence. Audio Nirvana have also produced 12″ and 15″ full range drivers and have used special bass reflex cabinets to overcome the bass limitations of smaller drivers. Also, since most adults are unable to hear above 15 kHz, the lack of high end frequency is usually not an issue with good quality full range drivers.
That about sums it up for today’s article. What do you guys think about full range speakers now? Do you still have faith in the capability of single-driver systems?
Let me know your thoughts down below, and be sure to share this article with your pals!