[WARNING !]
This app can be used for free for 3 days after the first subscription. You are not charged during the free trial period.

If it’s less than 48 hours since you bought a subscription, you can request a refund through Google Play.
A refund is not possible 48 hours after purchasing a subscription, due to company policy.
When you cancel a subscription you’ll still be able to use your subscription for the time you’ve already paid.

This app is optimized for Android version 8.1 (API 27) and higher versions. It may work in some phones with lower android version. Please make sure it works on your phone during the trial period.
If it does not work properly in versions below Android 8.1, selecting 'Normal' instead of the default 'Low Latency' in [Detail Settings> Advanced option> Performance] may work.

On Android versions lower than 8.1, [Settings > Advanced option > Audio API] option is automatically selected as 'OpenSL ES'. The things to remember in 'OpenSL ES' mode are as follows:
-When 'OpenSL ES' is selected as 'Audio API', it is recommended to use earphones with no built-in microphone or Bluetooth earphones/headsets.
-When 'OpenSL ES' is selected as 'Audio API', if the earphone with a built-in microphone is used, the microphone of the earphone is used.

If the subscription is cancelled during the trial period you will not be charged.

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.

It is a 64-channel personal sound amplifier app that minimizes the delay between external sound input and amplified sound heard through earphones using the latest technology.

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 8.1 (API 27) or higher.

This app can be used for free for 3 days after purchase, and if you subscribe, you can continue to use the advanced voice amplifier function even after this period.

The subscription policy is as follows:

- If you do not cancel your regular payment at least 24 hours before the end of the subscription period, it will renew automatically.

- After subscribing, you can manage your subscription history and cancel your subscription from the Subscriptions option in the Play Store menu.

- The remaining validity period after subscription cannot be canceled.

- Subscription options are monthly subscription and annual subscription.