When you’re designing a new sound system, what components, materials, and design aspects should be taken into consideration? Whether it’s for a consumer product, public space, or industrial application, you want to make sure that your system delivers the audio quality that you expect, it’s aesthetically pleasing, and it’s durable. Which also happens to be the three key elements of designing and integrating the speaker grill for your project. Speaker grills are often an afterthought but they can have a major impact on the quality of the speaker system you design.
What is the speaker grill?
The speaker grill is a cover that keeps dust, dirt, and other objects out of the more delicate components of the speaker. A speaker without a grill pumps out the best quality sound, and whatever is used to cover it can compromise that sound to some extent. The key here is to consider the application — if you’re going to need to protect the speaker from the elements, spills, vandals, or other possible impacts, there could be trade-offs in sound quality. Including the grill in the initial design will be a key to getting the end result you’re looking for.
For example, a speaker for a home stereo system doesn’t require anything more durable than a thin cloth covering or perhaps a very fine wire mesh because it’s in a controlled environment. In this case, acoustic transparency and aesthetics are the primary considerations. This would also be true of speakers for permanent installations like concert venues or houses of worship. The housing or cabinet may be larger or more durable to support the larger, heavier drivers, but the speaker grill will be minimal in order to project the highest quality sound for the sound being transmitted.
Protecting The Speaker
The more protection that the speaker needs, the more complicated the engineering. Take for instance a speaker inside a mass transit bus or subway system. The audio quality needs to be highly intelligible for a helpful and enjoyable rider experience but the speaker itself is unmonitored and out in the open — a potential target for vandals. In these cases the speaker is often mounted behind two grills - both made of metal with the holes offset to allow sound to penetrate and also protect the cone and more delicate parts underneath. In such an extreme case, the sound quality could be sacrificed, which is why it is important to work with your manufacturer to test how the grill affects the sound quality before final specification and installation.
Engineering Considerations of Metal Grills
Metal grills can provide the ultimate protection, however, there are a lot of engineering considerations. Material thickness is the first consideration — it should be thick enough to provide strong protection but thin enough to allow the sound to be released and not muffled. As a general rule, we have found that 60 percent of the grill should be open in order to provide enough acoustical transparency. Plus, the diameter of the holes in the metal needs to be at least as big, if not bigger than the thickness of the metal. Otherwise, each of those holes will turn into a mini resonant chamber, and become a definite acoustical challenge.
In addition to protecting against vandals, louvered aluminum speaker grills can be good protection against sun, wind, and rain in an outdoor environment.
Plastics can be a sensible and effective option when you’re thinking about mass-produced consumer products like smart speakers or soundbars. Popular products on the market today have combined the speaker grill into the housing or cabinet and covered the entire unit with a thin cloth or wire mesh outer grill for aesthetic reasons.
Finally, the location of the grill in relation to the speaker components is also important. Ideally, it should be placed as close to the speaker diaphragm (cone) as possible in order to deliver the sound directly through the opening. The grill must also be placed far enough away so that when the diaphragm vibrates, it doesn’t touch the grill which could lead to distortion.
All of these factors must be considered in speaker design. That’s why it’s critical that you consult with a designer/manufacturer and discuss your speaker application, location, and acoustic quality before you order.