🎚️ Audio Gain Adjuster

🎯 Overview

This tool is a simple utility for adjusting the volume (gain) of WAV/FLAC/ALAC files. You can increase or decrease the volume in the range of -10dB to +10dB. It adjusts only the gain while completely preserving the original file format (bit depth and sampling rate).

✨ Key Features

Simple Operation - Just drag and drop files and enter the adjustment gain value (+1.0, -1.5, etc.)
Multiple File Support - Process single or multiple files simultaneously
Individual Gain Settings - Specify different gain values for each file
Auto Clipping Adjustment - Automatically processes with maximum safe gain when clipping is detected
Metadata Preservation - Complete preservation of tag information and cover images
3 Format Support - Supports WAV/FLAC/ALAC (.m4a)
Gain Range - Adjustment from -10dB to +10dB

📌 Important Notes

ALAC Processing: Processing ALAC (.m4a) files requires ffmpeg (PATH registration or placement in the same folder as EXE)
Original File Protection: Original files are never modified. Adjusted files are created as new files

📦 Distributed Files

File Name	Description
`gain_adjuster.exe`	Executable file (approx. 22MB)
`gain_adjuster_ReadMe.html`	User manual (Japanese version)
`gain_adjuster_ReadMe_en.html`	User manual (this file - English version)

Note: This tool requires no installation. Simply place the EXE file in any location to use it.

📋 System Requirements

Item	Details
OS	Windows 10 or later
WAV/FLAC Processing	Works standalone (no additional software required)
ALAC Processing	Requires ffmpeg (PATH registration or placement in same folder)

About ffmpeg (for ALAC processing)

To process ALAC (.m4a) files, ffmpeg is required:

Method 1: Register ffmpeg in system PATH (recommended)
Method 2: Place ffmpeg.exe in the same folder as gain_adjuster.exe

Download ffmpeg: https://ffmpeg.org/download.html

📊 Supported File Formats

Item	Details
Supported Formats	WAV (8/16/24/32bit), FLAC, ALAC (.m4a)
Bit Depth	Output at same bit depth as input (no conversion)
Sampling Rate	Output at same rate as input (no resampling)
Channel Count	Any (mono, stereo, multi-channel supported)

Format Details

WAV

Bit Depth: 8/16/24/32bit (integer/floating point)
Sampling Rate: Any (output at same rate as input)
Metadata: ID3 tags, RIFF INFO tags
Processing: Direct read/write (fastest)

FLAC

Bit Depth: 16/24bit (lossless compression)
Sampling Rate: Any (output at same rate as input)
Metadata: Vorbis Comment + cover image
Processing: Uses soundfile library

ALAC (.m4a)

Bit Depth: 16/24bit (Apple Lossless)
Sampling Rate: Any (output at same rate as input)
Metadata: MP4 tags (iTunes format)
Processing: Convert to WAV via ffmpeg for processing

🚀 How to Use

Basic Usage

Drag and drop audio files (single or multiple) onto gain_adjuster.exe
Console window opens and displays the number of files
Enter gain adjustment value for each file (e.g., -2.5 or +3.0)
Press Enter to start processing
When processing is complete, new files are created in the same location as the original files
After all files are processed, a summary is displayed

💡 Gain Value Input Examples:

-2.5 - Decrease by 2.5dB
+3.0 - Increase by 3.0dB
1.5 - Increase by 1.5dB (+ sign can be omitted)
-5dB - Decrease by 5dB (dB notation also acceptable)

Multiple File Processing Example

Found 3 valid file(s)
============================================================
File 1/3: song1.wav
Enter gain adjustment value: -1.5
✓ Completed successfully

File 2/3: song2.flac
Enter gain adjustment value: +2.0
WARNING: Clipping detected at +2.0dB!
Auto-adjusting to maximum safe gain: +1.2dB
✓ Completed with auto-adjusted gain (+1.2dB)

File 3/3: song3.m4a
Enter gain adjustment value: +0.5
✓ Completed successfully

SUMMARY
============================================================
Processed: 3/3 files

Auto-adjusted files:
  - song2.flac: +2.0dB → +1.2dB

📊 Processing Specifications

Item	Specification
Gain Adjustment Range	-10dB to +10dB
Clipping Protection	Yes (auto detection & auto adjustment)
Metadata	Complete preservation (including tags and cover images)

📁 Output Files

Processed files are saved with the following naming convention:

File Name Examples

Original file: music.wav
After -2.5dB adjustment: music_-2.5dB.wav
After +3.0dB adjustment: music_+3.0dB.wav

Output Examples by Format

WAV: original_+2.0dB.wav
FLAC: original_-1.5dB.flac
ALAC: original_+3.0dB.m4a

⚠️ Auto Clipping Adjustment Feature

If clipping (audio distortion) would occur due to excessive gain increase, the tool automatically processes with the maximum safe gain value.

Auto Clipping Adjustment Example

Enter gain adjustment value: +5.0

Processing...
WARNING: Clipping detected at +5.0dB!
Peak level would be: +2.35dB over 0dBFS
Auto-adjusting to maximum safe gain: +2.5dB
  Peak level: 0.998 (OK)

✓ Completed with auto-adjusted gain (+2.5dB)

Benefits:

Completely avoids clipping
Applies the highest possible gain
No need to re-run
Processing does not stop midway

❓ Troubleshooting

"ffmpeg not found" error (during ALAC processing)

Cause: ffmpeg is not found for ALAC (.m4a) file processing.

Solution:

Register ffmpeg in system PATH
Or place ffmpeg.exe in the same folder as gain_adjuster.exe

Processing is slow

Causes and Solutions:

ALAC processing: Takes longer than other formats due to ffmpeg conversion (normal operation)
Large files: Processing time is proportional to file size
Multiple files: Sequential processing takes file count × processing time

🎓 Technical Specifications

Gain Calculation: Accurate volume adjustment using linear gain (10^(dB/20))
Processing Precision: High-precision processing with float64 (double precision floating point)
Audio Quality Degradation: Theoretically no quality degradation due to processing at same bit depth and sampling rate

🔒 Security Information

VirusTotal Scan Results

This EXE file has been scanned by third-party organization VirusTotal:

Result: 3/72 detections (False Positive)
Scan Results URL: View VirusTotal Results

Detection Engines (3):

Bkav - Pro W64.AIDetectMalware
Jiangmin - Trojan.Generic.hunjo
Zillya - Trojan.Blank.Script.976

About False Positives:

Not detected by major security software (Windows Defender, Kaspersky, Avast, AVG, Avira, ESET-NOD32, McAfee, Norton, Symantec, etc.)
69 out of 72 engines judged it as "safe"
Contains no malicious code
This is a false positive pattern for some engines against Python scripts converted to EXE

⚠️ About Download Warnings

Browsers may warn of a "dangerous file," but this is a false positive.

For Chrome:

"Dangerous file" is displayed in the download bar
Click "^" to the right of the file name
Click "Keep" or "Continue"

For Microsoft Edge:

"This file can't be downloaded safely" is displayed
Click "..." (details)
Click "Keep"

⚠️ About First Run Warning

Windows Defender (SmartScreen) may display a warning, but this is a false positive:

"Windows protected your PC" is displayed
Click "More info"
Click "Run anyway" button

📄 Disclaimer

Notes on Use

Use of this tool is at your own risk.
The developer assumes no responsibility for any changes or loss of audio quality resulting from audio file processing.
For commercial use, please comply with relevant copyright laws and license agreements.
The developer assumes no responsibility for any damage caused by the operation of this tool.

📄 License

This tool is free to distribute and use.

🧑‍💻 Developer Information

Developer	Noriya
Email	noriyahd28v@gmail.com
URL	http://noriya.info/

This tool was developed to provide music enthusiasts with a better music experience.
If you have any questions or feedback, please feel free to contact us using the above information.

Audio Gain Adjuster - Universal Audio Volume Adjustment Tool