All mobile phone users have the same limitation: In noisy environments they cannot clearly hear or easily understand what is said to them. Automatic volume controls (AVCs) on phones and Bluetooth headsets today try to compensate for background noise by maintaining constant signal-to-noise ratio (S/N) one way or another. But these first-generation AVCs are not a popular solution, because constant S/N in a fluctuating noise environment produces the impression of unclear or ‘muddy’ speech.

SmartAVC™ ignores S/N, and instead adjusts volume automatically to maintain constant intelligibility of speech. The patented algorithms characterize the noise background in the frequency domain and in the time domain, and only compensate for noise that has frequency content and time duration sufficient to degrade intelligibility. The weighting of noise frequencies by the preferred speech interference level (PSIL) and the low-pass filtering of noise spikes by the damped, driven harmonic-oscillator (shock-absorber) equation are discussed. A live interactive demonstration (downloadable at StarmarkTechnologies.com) illustrates the advantages of this next-generation AVC, including: Controlling volume without sacrificing clarity; adjusting only for persistent speech-interference noise; smoothing volume fluctuations; and eliminating static-like bursts caused by noise spikes. In the near future, the SmartAVC™ algorithms may be implemented on phones, with no changes to handsets needed, in any of these ways – in software applications, in the operating system, or in hardware at the chipset level or on a DSP.