Regardless of whether you are buying a directional speaker for a home theater system, or an inexpensive hi-fi speaker for your living room from Focusonics, there are a number of different factors that will affect the quality of sound. For example, the amounts of transducers on the speaker, the directivity of the wave-producing source, the size of the source compared to the wavelengths it is generating, and the off-axis frequency response of the speaker will all play a role in how the sound will be reproduced.
Different Use Cases of Conventional Loudspeakers
Traditionally, conventional loudspeakers are more suited for applications where sound is needed to be widespread. They also provide better sound quality and higher efficiency than directional speakers. But new designs allow for a variety of use cases, from immersive entertainment to active noise cancellation in clamorous environments.
For example, researchers at the Massachusetts Institute of Technology (MIT) recently redesigned a thin-film loudspeaker, a design that can be used for immersive entertainment or you can use directional audio for museums. In addition to providing minimal power consumption, the thin-film loudspeaker is ideal for smart devices with limited battery life. It also has the ability to generate sound in an opposite phase.
To produce sound, the thin-film loudspeaker uses a mechanical bias force that causes the film to vibrate unidirectionally when driven electrically by DC bias voltage. The film is bonded to a thin sheet of PET, a lightweight plastic, which is laminated to a thin film of PVDF, a piezoelectric material. This combination produces a high-frequency sound.
Directivity of wave-producing sources
During the past few years, directional speaker technology has come a long way. They are small, affordable, and can be used for both public announcements and private spaces. They can be installed in a ceiling or mounted on a wall. They are great for broadcasting custom announcements and can even play location-specific music.
In order to achieve high directivity, a wave-producing source must be large enough to produce a directional beam. A small speaker array can produce an equivalent directivity but its amplitude will vary depending on the size.
A typical array of four loudspeakers has a non-radiating gap on each end. It is usually designed to maximize the radiating percentage. It can also be phased to mitigate sidelobes.
Size of the source compared to the wavelengths it is generating
Choosing the right loudspeaker for your application is not as daunting as it sounds. A good ol’ fashioned consult with a competent sound designer can go a long way to ensure optimal results. It is also important to remember that not all venues are created equal. Some venues may be more conducive to your musical endeavors than others. Luckily, there is a large selection of venues to choose from. Whether you’re looking to hire a music or entertainment professional, or you’re looking for a new venue to host your next big event, there’s a host of options on tap.
Number of transducers
Generally speaking, the number of transducers in a directional speaker is less than the number of speakers in a conventional speaker. The aforementioned number is not all that surprising when you consider that directional speakers do not make use of a moving electromagnetic coil to create their sound. Moreover, the directional capabilities of a loudspeaker can be greatly improved with the aid of a good ol’ fashion spatial processor. In other words, a directional speaker can be as compact as it is powerful. A 750 mm (30 inches) tall array of piezoelectric transducers can be used to control both horizontal and vertical plane directivity.
Off-axis frequency response
Compared to conventional speakers, directional speakers have a superior off-axis frequency response. This is because a large percentage of the reflected sound is out of phase with the direct radiated sound. This results in time smearing of high frequencies and loss of intelligibility.
The off-axis frequency response of directional speakers is also compromised by the vertical offset of the drivers. The vertical offset causes interference patterns and lobing errors. In addition, it distorts the imaging of the sound.
This problem is especially serious for large line arrays. The large number of drivers in such systems disrupts the time alignment of the high frequency response across the frequency band.
Studio monitors vs regular hi-fi speakers
Generally, studio monitors have the following characteristics. They are generally active and have a built-in power amplifier. They are also made of tough materials.
They are designed to produce a relatively flat frequency and phase response. These factors are important for a high-quality sound stage.
However, they are not all the same. Some are designed to give more sound dispersion, while others are designed to produce an unaltered sound.
They can be used in both home stereo systems and in the professional audio industry. Some are passive, while others need an external power amplifier. They are designed to give an excellent sound in any environment.
Getting a perfect frequency response
Getting a perfect frequency response from a directional speaker isn’t as easy as putting a microphone in front of a speaker box. It’s a matter of matching the right driver with the right baffle. The big question is: is it worth the trouble? The good news is that a well-engineered directional speaker can deliver a solid bass response while still maintaining crisp mids and treble. A little bit of tinkering with the driver compartment can make a major difference to your bottom line. With a little bit of elbow grease, a directional speaker can perform like the champ.