Task

• To improve the sound quality, loudness, and speech intelligibility of a nurse-call handset product.

Challanges

• The sound quality issue was critical, as the commercialization of the handset could not proceed without solving this particular problem.
• Several acoustical consulting companies had tried unsuccessfully to resolve the audio quality issue before we intervened.
• Very limited real estate was available inside the handset.
• The electronics could not be modified to boost the sound output; the solution had to be purely passive.
• The handset needed to be hermetically sealed, creating a barrier for sound transmission.

How we helped

• Employed an acoustical "trick" to naturally boost sound output without additional amplification.
• Performed acoustical measurements before and after our intervention.
• Advised on the best possible loudspeaker component to use given the dimensional constraints.
• Designed a loudspeaker enclosure that could fit within the limited space inside the handset.
• Designed loudspeaker ports and provided advice on a waterproof membrane.

Results

• Thanks to our design, the sound output was boosted by +6 dB without any additional amplification.
• Bass response and audio quality were significantly improved.
• We removed the project roadblock that was preventing the commercialization of the product.