How THC works
Questions,
answered.
This page explains features and setup. For data collection, storage, third-party services, your controls, and content responsibility, read the separate User Agreements.
Core questions
Features and setup
Practical answers without mixing product guidance with the legal and data disclosure.
Open the full wikiWhat is The Harmonic Client?
THC is a client-side Minecraft audio visualizer for Fabric and NeoForge. It analyzes audio playback and turns frequency, level, and timing data into world geometry, particles, dynamic light, widgets, and synchronized lyrics.
Does THC provide or host audio?
No. THC can play local files or resolve provider links chosen by the user, but it is not an audio catalog or hosting service. The agreements explain user responsibility for selected audio and provider terms.
Are direct downloads and Modrinth builds different?
Direct downloads are the canonical release. Modrinth may also host the identical canonical jars after moderation completes, with launcher integration and its own listing history. Compare the published SHA-256 values to verify a mirror byte-for-byte.
Does the mod jar contain executable programs?
No executable is bundled in the Fabric or NeoForge jar. Every canonical jar can download pinned yt-dlp and FFmpeg packages only after explicit consent and SHA-256 verification.
Do I need THC installed on the Minecraft server?
No for local audio visuals or the optional external relay. A server-side THC component is only needed when administrators want server-provided audio, request moderation, or direct server-channel synchronization.
What are parties and the cross-server relay?
Parties let verified players share playback position, visualizer state, and party actions even when they are on different Minecraft servers. The relay uses a version-independent THC protocol, so ViaVersion-style mixed Minecraft client versions can participate when their THC protocol is compatible.
What are yt-dlp and FFmpeg used for?
yt-dlp resolves supported provider links into playable media information. FFmpeg, FFprobe, and FFplay decode, inspect, and play audio. Local-file visualization and other THC features can still work without provider-link tools.
How do world visualizers differ from the HUD widget?
World visualizers render around a player in Minecraft space and can be visible to other THC users. The HUD widget is a personal screen overlay with track details, controls, lyrics, and a compact spectrum. They can be configured independently.
Which lyric writing systems are supported?
World lyrics support Latin and extended Latin characters, Cyrillic, Hangul, Japanese kana and kanji, Chinese Han characters, and Arabic text. Minecraft font availability and resource packs can still affect the exact glyph appearance.
What does true dynamic lighting do?
It projects audio-reactive colored light onto nearby world surfaces, including non-full blocks and transparent-material paths where supported. Bloom is a separate visual glow layer and can be tuned independently for performance and appearance.
How does updating work?
Minecraft 1.21.1 is the source-of-truth version and is updated first. Other supported versions are selected for porting afterward based on compatibility work and testing needs, so their order can vary. Official builds can show a non-blocking update notice but never install a new mod jar automatically.
Where should I report a bug or request a feature?
Use the public THC Issues repository. Include the Minecraft version, loader, THC version, renderer, relevant logs, and clear reproduction steps. Never include passwords, access tokens, or private account information.