[WARNING !]
If you use a sound amplifier without a doctor's prescription, your hearing can get worse.
Be sure to plug-in your earphone or pair your bluetooth headset with your mobile phone before starting the app.

If It’s less than 48 hours since you bought an app, you can request a refund through Google Play.
A refund is not possible 48 hours after purchasing an app, due to company policy.

AlgorKorea's hearing aid firmware & app development technology created Personal Sound Amplifier (PSA) app that performs microphone & receiver calibration, includes all of the same four features as a smart hearing aid. The Personal Sound Amplifier app produces loud volume for profound hearing loss.

64 Channel Nonlinear precise Compression, Noise Reduction based on probabilistic analysis and Feedback Cancellation are the main features of AlgorKorea sophisticated Personal Sound Amplifier app. All of the three algorithms are implemented in real-time with high sound quality for hearing impairments.

The output audio level may be slightly different based on mobile phone’s volume settings, microphone and earphone/headset types.

Just make sure your Android version is 6.0 (API23) or higher.