How to Produce Sound Without Speakers

This article explains how to produce sound without visible speakers.

Use a Wall, Window, or Other Solid Surfaces

Designed by MSE, Solid Drive is a technology that produces sound without any visible speakers. The core of Solid Drive is a voice coil/magnet assembly that is encased in a short, sealed, aluminum cylinder.

When one end of the cylinder is attached to the speaker terminals of an amplifier or receiver, and the other end is placed flush with drywall, glass, wood, ceramic, laminate, or other compatible surfaces, listenable sound results.

The sound quality is on par with a modest speaker system, able to handle up to about 50 watts of power input, with a low-end response of about 80Hz, but with a low high-end drop-off point at about 10kHz.

Other examples of devices similar in concept to MSE's Solid Drive, but more suited to portable use (such as with smartphones and laptop PCs), include the vSound Box.

Also, if you are adventurous, you can even make your own. For details, check out the How To Make A "Vibration Speaker" video on YouTube.

Use a TV Screen

Today's TVs are getting so thin that trying to squeeze the speaker system into them is getting more difficult.

As a possible solution, in 2017, LG Display and Sony announced that they had developed technology similar to the Solid Drive concept that enables an OLED TV screen to produce sound. For marketing purposes, LG Display uses the term Crystal Sound while Sony uses the term Acoustic Surface.

This technology employs a thin exciter placed within an OLED TV panel structure and connected to the TV's audio amplifier. The exciter vibrates the TV screen to create sound.

Experiencing this tech hands-on, if you touch the screen you can feel the vibrations. However, you cannot see the screen vibrating. The screen vibrations do not affect image quality. Also, since the exciters are located horizontally behind the screen and vertically at the center level of the screen, sounds are more accurately placed in a stereo soundstage.

Even though both exciters are vibrating the same OLED panel, the panel/exciter construction is such that the left and right channels are isolated enough to produce a true stereo sound experience if the sound mix includes separate left and right channel cues. The perception of the stereo sound field also depends on the screen size, with larger screens providing more distance between the left and right channel exciters.

The exciters produce mid-range and high frequencies, but they don't do well with lower frequencies needed for full-bodied sound. To compensate for this gap, an extra-but-compact traditional slim-profile speaker mounts to the bottom of the TV (so as not to add thickness to the screen) for lower frequencies. Also, lower frequencies vibrate the screen more aggressively, which, in turn, might make screen vibrations visible, which would affect image quality.

On the other hand, the overall Crystal Sound/Acoustic Surface approach is undoubtedly an audio solution for ever-thinner OLED TVs—apart from connecting the TV to a more capable soundbar or home theater receiver and speakers.

The LG Display/Sony Crystal Sound/Acoustic Surface TV audio solution, as of this point, is only available on OLED TVs. Since LCD TVs require an added layer of LED edge or backlighting, which adds more structural complexity, implementation of Crystal Sound/Acoustic Surface technology would be more difficult.

The Acoustic Surface audio solution is available on Sony OLED TVs. LG is expected to produce Crystal Sound-branded OLED TVs at some point.

Do You Need Speakers to Produce Sound?

To hear sound from smartphones, stereos, home theater systems, and TVs, you need speakers. Even headphones, earphones, and earbuds are just tiny speakers. Speakers generate sound by moving air through a cone, horn, ribbon, or metal screen. However, alternative technologies work, too, and they might even be better aligned to specific use cases.