Audio Volume Adjuster

① Faint Lectures & Conference Voice Memos:

- Boost whispered dialogue recorded far from the microphone by 200% to 300% for effortless transcription.

② Smartphone Ringtone & Notification Loudness:

- Boost custom ringtone tracks so incoming calls are never missed inside pockets or bags.

③ YouTube & Podcast Audio Level Matching:

- Balance audio tracks recorded at uneven microphone levels to prevent listener volume fatigue.

④ Noisy Commute Audiobooks & ASMR:

- Amplify quiet audiobook narrations for comfortable earphone listening on buses and subways.

① Linear Gain Multiplier:

- Each PCM audio sample $x[n]$ is directly multiplied by gain factor $G$ (e.g. $200\% = 2.0$): $y[n] = x[n] \times G$.

② Decibel Conversion Formula:

- In acoustics, the decibel increase $\Delta dB$ corresponding to gain multiplier $G$ is:

$$\Delta dB = 20 \times \log_{10}(G)$$

- For example, $2\times$ boost ($G=2.0$) equals $+6.02\text{ dB}$, $3\times$ ($G=3.0$) equals $+9.54\text{ dB}$, and $5\times$ ($G=5.0$) equals $+13.98\text{ dB}$.

③ Hyperbolic Tangent Soft-Clipping Limiter:

- For over-amplified peaks where $y[n] > 1.0$, applying $\tanh(y[n])$ prevents harsh rectangular hard clipping, introducing smooth analog-style warmth.

① Consider the Background Noise Floor:

- Boosting gain amplifies background room hiss and fan noise along with vocals. Keeping gain near 200% avoids noise fatigue.

② Keep the Anti-Clipping Limiter Checked:

- For audio with loud drum transients or plosive consonants (P, T, K), the limiter prevents harsh speaker distortion.

③ Download Lossless WAV First:

- Archiving the boosted master as 16-bit uncompressed WAV ensures zero generational loss before converting to MP3 or AAC.