Knowles Sound Solutions has launched a specially developed material called N’Bass Virtual Back Volume, designed to improve the acoustic performance of speakers in devices with small form factors. N’Bass stands for ‘enhanced bass’ and it increases the apparent back volume seen by the loudspeaker driver by up to 100%. It can provide better acoustic performance – specifically more bass – or enable smaller loudspeaker box designs while maintaining the same performance. It also facilitates the use of bigger drivers to provide better sound performance in the same total volume.
Similar to a sponge, the new material adsorbs air in the sealed loudspeaker box when the speaker membrane moves inward and releases the air again when the membrane moves outward, making it easier for the membrane to vibrate at full amplitude – especially at low bass frequencies. In this way, it virtually increases the available back volume for the loudspeaker that is typically very limited in mobile devices due to space constraints. In speakers using the new material, the manufacturer has measured a difference in the resonance frequency of about 150 Hz, with a sound pressure level boost below the resonance frequency of approximately 3 dB compared to a standard loudspeaker enclosure.
The material is non-conductive and has no negative effect on antenna performance.