Acoustic cloth: one term, two very different worlds

A clear distinction between sound-absorbing textiles and sound-transparent speaker fabric

The term acoustic fabric or acoustic cloth is often used rather loosely and can easily lead to misunderstandings. Many people assume that it simply refers to any fabric associated with sound. Within the acoustics industry, however, the distinction is very clear. On one side are sound-absorbing textiles, which are designed to absorb sound energy, improving a room's acoustic environment. On the other are acoustically transparent speaker fabrics, such as those supplied by Akustikstoff.com. These fabrics allow sound waves to pass through with virtually no obstruction, preserving the original sound without audible colouration.
Both categories have their place. Their properties, however, and the applications for which they are intended could hardly be more different.

The common misconception: sound-absorbing materials

Sound-absorbing textiles are materials specifically developed to absorb sound energy and thereby reduce reverberation or simply lower the overall noise level within a room. They are generally densely woven, comparatively heavy and often feature a soft, fibrous or porous surface. Typical examples include stage molton, heavyweight velour fabrics and specialist acoustic curtains. They are used wherever sound needs to be attenuated, such as theatres, cinemas, recording studios, open-plan offices and concert halls. More precise terms for these materials would be acoustic curtain, sound-absorbing fabric or sound-insulating fabric. The expression acoustic textile is also occasionally encountered. Referring to these materials simply as acoustic fabric, however, is potentially misleading, because that term more accurately describes textiles that allow sound to pass through with as little alteration as possible.

Acoustic cloth is sound-transparent covering fabric

The acoustically transparent fabrics supplied by Akustikstoff.com represent the exact opposite of sound-absorbing textiles. They have been specifically engineered to allow sound waves to pass through with virtually no loss and no audible colouration. A high-quality acoustic fabric is characterised by its open structure, which presents only minimal resistance to sound waves. Measurements carried out on the fabrics supplied by Akustikstoff.com show that sound level attenuation across the audible frequency range generally remains below 1 decibel. Such a small reduction is scarcely perceptible to the human ear and has no meaningful effect on sound quality.

When acoustic transparency really matters

Typical applications for acoustically transparent fabric range from traditional loudspeaker grilles and architecturally integrated sound systems to exhibition construction, as well as the construction of acoustic absorbers, diffusers, and ceilings for domestic interiors, home cinemas, and professional recording studios. Sound-transparent fabrics are also used in organ building and even in highly specialised technical applications. In all of these applications, the objective is the same: sound should pass through the fabric with as little interference as possible. And because the covering fabrics supplied by Akustikstoff.com also allow infrared signals to pass through without obstruction, they are equally well suited to elegantly designed AV furniture with concealed audio and video equipment. 
Particular attention must be paid to higher frequencies, which are especially susceptible to absorption and scattering because of their comparatively low energy. Positioned in front of a loudspeaker, an unsuitable fabric can noticeably reduce detail, clarity, and openness. Installed over an acoustic absorber, it may significantly diminish the absorber's intended performance and, in the worst case, even introduce unwanted sound reflections.
For this reason, our fabrics are designed to provide an exceptionally linear transmission of sound across the entire audible frequency spectrum—and well beyond it.