Audio Guide
Everything you need to know about audio loudness, normalization, and recording tips for professional-sounding results.
In This Guide
What is Audio Loudness?
Audio loudness refers to how loud audio is perceived by the human ear. Unlike simple volume or peak levels, loudness takes into account how we actually hear sound. Our ears are more sensitive to certain frequencies (especially mid-range frequencies where speech occurs), so loudness measurement weighs these frequencies accordingly.
This distinction matters because two audio files can have the same peak volume but sound completely different in terms of perceived loudness. A whisper and a shout might both hit the same peak level, but the shout sounds much louder because it sustains that energy over time.
Understanding LUFS
LUFS stands for Loudness Units relative to Full Scale. It's the industry-standard measurement for audio loudness, developed as part of the EBU R128 broadcast standard. LUFS measures the average perceived loudness of audio over time.
Key LUFS Concepts
- Integrated Loudness: The average loudness of the entire audio file
- Short-term Loudness: Loudness measured over 3-second windows
- Momentary Loudness: Loudness measured over 400ms windows
- True Peak: The absolute maximum level, including inter-sample peaks
LUFS values are always negative (below 0). A higher number (like -14 LUFS) is louder than a lower number (like -24 LUFS). Think of 0 as the maximum possible loudness, and everything else measured relative to that ceiling.
What is Loudness Normalization?
Loudness normalization is the process of adjusting audio to meet a specific loudness target. Instead of just turning the volume up or down, it ensures your audio hits a precise LUFS level that matches industry or platform standards.
Linear vs. Dynamic Normalization
Linear Normalization
Applies the same gain adjustment to the entire track. Quiet parts stay quiet, loud parts stay loud.
Best for: Music, where preserving dynamics is important
Dynamic Normalization
Continuously adjusts volume throughout the track to maintain consistent loudness.
Best for: Podcasts, audiobooks, and speech content
Platform Loudness Standards
Different platforms have different loudness requirements. If your audio is too loud or too quiet, the platform will normalize it anyway, which can affect quality. It's best to deliver audio at the correct loudness from the start.
| Platform | Target LUFS | True Peak |
|---|---|---|
| Spotify | -14 LUFS | -1 dBTP |
| Apple Music | -16 LUFS | -1 dBTP |
| YouTube | -14 LUFS | -1 dBTP |
| Apple Podcasts | -16 LUFS | -1 dBTP |
| Amazon Music | -14 LUFS | -2 dBTP |
| Broadcast TV (EBU R128) | -23 LUFS | -1 dBTP |
Audio File Formats Explained
Understanding audio formats is essential for choosing the right one for your needs. The main distinction is between lossless and lossy compression.
Lossless Formats
Preserve 100% of the original audio data. Perfect quality but larger file sizes.
Best for: Archiving, professional work, mastering
Lossy Formats
Discard some audio data to achieve smaller files. Quality varies by bitrate.
Best for: Streaming, portable devices, web
Format Reference
WAV (Waveform Audio)
The standard uncompressed audio format. Highest quality with no compression at all. Large files (about 10 MB per minute for CD quality). Universal compatibility.
Use for: Recording, editing, archiving masters, professional production
FLAC (Free Lossless Audio Codec)
Lossless compression that reduces file size by 50-60% while preserving perfect quality. Open source and widely supported. Supports metadata and album art.
Use for: Music archiving, audiophile listening, lossless distribution
AIFF (Audio Interchange File Format)
Apple's uncompressed audio format, equivalent to WAV. Common in Mac/iOS environments and professional audio software like Logic Pro.
Use for: Mac-based production, Logic Pro projects, Apple ecosystem
MP3 (MPEG Audio Layer III)
The most universal audio format. Excellent compression with good quality at 256-320 kbps. Compatible with virtually every device and platform.
Use for: General distribution, podcasts, universal compatibility
AAC (Advanced Audio Coding)
More efficient than MP3, offering better quality at the same bitrate. The default format for Apple Music, iTunes, and YouTube. Supports higher sample rates.
Use for: Apple devices, streaming services, video soundtracks
OGG Vorbis
Open-source alternative to MP3 with better quality at lower bitrates. Popular in gaming and open-source software. Not as widely supported on consumer devices.
Use for: Games, open-source projects, Spotify
OPUS
The newest and most efficient codec. Excellent for voice and music, with very low latency. Used by Discord, WhatsApp, and WebRTC for real-time communication.
Use for: Voice chat, streaming, low-bandwidth situations
M4A (MPEG-4 Audio)
Container format typically containing AAC audio. Standard for Apple Music and iTunes purchases. Can also contain Apple Lossless (ALAC) audio.
Use for: Apple ecosystem, audiobooks, iTunes
Advanced Conversion Settings
Understanding these parameters helps you make the right choices for your specific needs.
Bitrate
Measured in kbps (kilobits per second), bitrate determines how much data is used per second of audio. Higher bitrate = better quality but larger files.
- 64-96 kbps: Voice/speech only, very small files
- 128 kbps: Acceptable quality for casual listening
- 192 kbps: Good quality, noticeable improvement
- 256 kbps: Very good quality, hard to distinguish from CD
- 320 kbps: Maximum for MP3, near-transparent quality
Sample Rate
Measured in Hz or kHz, sample rate is how many times per second the audio is sampled. Higher rates capture more detail, especially in high frequencies.
- 44.1 kHz: CD quality, standard for music
- 48 kHz: Video/broadcast standard
- 96 kHz: High-resolution audio
- 192 kHz: Studio archival quality
Channels (Mono vs Stereo)
Mono uses one audio channel, stereo uses two (left and right). Stereo files are twice the size of mono.
- Mono: Best for voice, podcasts, phone audio
- Stereo: Required for music, spatial audio, immersive content
VBR vs CBR
Variable Bit Rate (VBR) adjusts bitrate based on complexity; Constant Bit Rate (CBR) uses the same bitrate throughout.
- VBR: Better quality per file size, recommended for most uses
- CBR: Predictable file sizes, required for some streaming applications
Introduction to Mastering
Mastering is the final step in audio production, where a finished mix is prepared for distribution. It ensures your audio sounds polished, consistent, and translates well across different playback systems.
What Mastering Involves
EQ & Tonal Balance
Fine-tuning frequencies to ensure the audio sounds balanced across all systems.
Compression & Dynamics
Controlling the dynamic range to ensure consistent listening levels.
Limiting & Loudness
Maximizing perceived loudness while preventing clipping and distortion.
Stereo Enhancement
Widening or focusing the stereo image for better spatial presentation.
While our online converter handles loudness normalization and basic repairs, professional mastering requires specialized tools and trained ears. For music production, we recommend working with a professional mastering engineer or using dedicated mastering software.
Professional Mastering Tools
For musicians and producers who need professional-grade mastering, check out MajorDecibel - our sister product offering intelligent mastering and advanced audio processing tools designed for music production.
Visit MajorDecibelTips for Better Recordings
The best audio starts with a good recording. While our AI repair tools can fix many issues, getting it right at the source will always give you the best results.
Get Close to the Microphone
Position yourself 4-8 inches from the mic. This improves the signal-to-noise ratio, meaning your voice is louder relative to background noise. Use a pop filter to prevent plosives (harsh "p" and "b" sounds).
Minimize Background Noise
Turn off fans, air conditioning, and other noisy appliances. Close windows to block traffic noise. Record in a quiet room with soft furnishings that absorb sound reflections.
Set Proper Recording Levels
Aim for peaks around -12 to -6 dB. This gives you headroom to prevent clipping while keeping the signal strong enough above the noise floor. Never let levels hit 0 dB (the red zone).
Use a Consistent Environment
If recording multiple sessions (like podcast episodes), use the same room, mic position, and settings. This ensures consistent sound across all your content.
Monitor While Recording
Use headphones to monitor your recording in real-time. This helps you catch issues like clipping, background noise, or mic bumps before they ruin a take.
Common Audio Problems & Fixes
Clipping & Distortion
Cause: Recording levels were too hot, causing the signal to exceed the maximum level.
Fix: Our Fix Clipping tool uses limiting and soft compression to reduce the audibility of clipped peaks. For best results, re-record with lower input levels if possible.
Background Noise & Hum
Cause: HVAC systems, electrical interference, traffic, or room ambience picked up by the microphone.
Fix: Our AI Noise Reduction analyzes and removes unwanted background noise while preserving voice clarity. Works especially well on speech and vocal recordings.
Clicks, Pops & Crackle
Cause: Digital glitches, vinyl surface noise, mouth clicks, or connection issues during recording.
Fix: Our Remove Clicks & Pops tool uses intelligent detection to identify and remove these transient noises without affecting the underlying audio.
Inconsistent Volume
Cause: Speaker moving closer/further from mic, or natural volume variation in speech.
Fix: Use Dynamic loudness normalization to even out volume variations throughout the recording, ensuring consistent listening levels.
Dead Air & Long Silences
Cause: Pauses before/after recording, or extended silences during the content.
Fix: Our Trim Silence tool automatically removes silence from the start, end, or throughout your audio, tightening up the content.
How Online Audio Converter Helps
Our free online tool combines professional audio conversion with intelligent repair features, making it easy to get broadcast-ready audio without expensive software or technical expertise.
One-Click AI Repair
- Remove clicks, pops, and crackle
- Fix clipping and distortion
- Intelligent noise reduction
- Automatic silence trimming
Professional Loudness Control
- Target specific LUFS levels
- Linear or dynamic normalization
- Meet platform requirements
- Preview before converting
No signup required. Convert and repair audio instantly.