feat: add band_extract audio source type for frequency band filtering

New audio source type that filters a parent source to a specific frequency
band (bass 20-250Hz, mid 250-4kHz, treble 4k-20kHz, or custom range).
Supports chaining with frequency range intersection and cycle detection.
Band filtering applied in both CSS audio streams and test WebSocket.

TODO-css-improvements.md

@@ -24,7 +24,7 @@
 
 ## New Source Types
 
-- [ ] **`weather`** — Weather-reactive ambient: maps weather conditions (rain, snow, clear, storm) to colors/animations via API
+- [x] **`weather`** — Weather-reactive ambient: maps weather conditions (rain, snow, clear, storm) to colors/animations via API
 - [ ] **`music_sync`** — Beat-synced patterns: BPM detection, energy envelope, drop detection (higher-level than raw `audio`)
 - [ ] **`math_wave`** — Mathematical wave generator: user-defined sine/triangle/sawtooth expressions, superposition
 - [ ] **`text_scroll`** — Scrolling text marquee: bitmap font rendering, static text or RSS/API data source *(delayed)*
@@ -53,7 +53,7 @@ Need to research HAOS communication options first (WebSocket API, REST API, MQTT
 
 ### `audio`
 
-- [ ] New audio source type: band extractor (bass/mid/treble split) — responsibility of audio source layer, not CSS
+- [x] New audio source type: band extractor (bass/mid/treble split) — responsibility of audio source layer, not CSS
 - [ ] Peak hold indicator: global option on audio source (not per-mode), configurable decay time
 
 ### `daylight`

server/src/wled_controller/api/routes/audio_sources.py

@@ -42,6 +42,9 @@ def _to_response(source: AudioSource) -> AudioSourceResponse:
         audio_template_id=getattr(source, "audio_template_id", None),
         audio_source_id=getattr(source, "audio_source_id", None),
         channel=getattr(source, "channel", None),
+        band=getattr(source, "band", None),
+        freq_low=getattr(source, "freq_low", None),
+        freq_high=getattr(source, "freq_high", None),
         description=source.description,
         tags=source.tags,
         created_at=source.created_at,
@@ -52,7 +55,7 @@ def _to_response(source: AudioSource) -> AudioSourceResponse:
 @router.get("/api/v1/audio-sources", response_model=AudioSourceListResponse, tags=["Audio Sources"])
 async def list_audio_sources(
     _auth: AuthRequired,
-    source_type: Optional[str] = Query(None, description="Filter by source_type: multichannel or mono"),
+    source_type: Optional[str] = Query(None, description="Filter by source_type: multichannel, mono, or band_extract"),
     store: AudioSourceStore = Depends(get_audio_source_store),
 ):
     """List all audio sources, optionally filtered by type."""
@@ -83,6 +86,9 @@ async def create_audio_source(
             description=data.description,
             audio_template_id=data.audio_template_id,
             tags=data.tags,
+            band=data.band,
+            freq_low=data.freq_low,
+            freq_high=data.freq_high,
         )
         fire_entity_event("audio_source", "created", source.id)
         return _to_response(source)
@@ -126,6 +132,9 @@ async def update_audio_source(
             description=data.description,
             audio_template_id=data.audio_template_id,
             tags=data.tags,
+            band=data.band,
+            freq_low=data.freq_low,
+            freq_high=data.freq_high,
         )
         fire_entity_event("audio_source", "updated", source_id)
         return _to_response(source)
@@ -182,17 +191,28 @@ async def test_audio_source_ws(
         await websocket.close(code=4001, reason="Unauthorized")
         return
 
-    # Resolve source → device info
+    # Resolve source → device info + optional band filter
     store = get_audio_source_store()
     template_store = get_audio_template_store()
     manager = get_processor_manager()
 
     try:
-        device_index, is_loopback, channel, audio_template_id = store.resolve_audio_source(source_id)
+        resolved = store.resolve_audio_source(source_id)
     except ValueError as e:
         await websocket.close(code=4004, reason=str(e))
         return
 
+    device_index = resolved.device_index
+    is_loopback = resolved.is_loopback
+    channel = resolved.channel
+    audio_template_id = resolved.audio_template_id
+
+    # Precompute band mask if this is a band_extract source
+    band_mask = None
+    if resolved.freq_low is not None and resolved.freq_high is not None:
+        from wled_controller.core.audio.band_filter import compute_band_mask
+        band_mask = compute_band_mask(resolved.freq_low, resolved.freq_high)
+
     # Resolve template → engine_type + config
     engine_type = None
     engine_config = None
@@ -233,6 +253,11 @@ async def test_audio_source_ws(
                     spectrum = analysis.spectrum
                     rms = analysis.rms
 
+                # Apply band filter if present
+                if band_mask is not None:
+                    from wled_controller.core.audio.band_filter import apply_band_filter
+                    spectrum, rms = apply_band_filter(spectrum, rms, band_mask)
+
                 await websocket.send_json({
                     "spectrum": spectrum.tolist(),
                     "rms": round(rms, 4),

server/src/wled_controller/api/schemas/audio_sources.py

@@ -10,14 +10,18 @@ class AudioSourceCreate(BaseModel):
     """Request to create an audio source."""
 
     name: str = Field(description="Source name", min_length=1, max_length=100)
-    source_type: Literal["multichannel", "mono"] = Field(description="Source type")
+    source_type: Literal["multichannel", "mono", "band_extract"] = Field(description="Source type")
     # multichannel fields
     device_index: Optional[int] = Field(None, description="Audio device index (-1 = default)")
     is_loopback: Optional[bool] = Field(None, description="True for system audio (WASAPI loopback)")
     audio_template_id: Optional[str] = Field(None, description="Audio capture template ID")
     # mono fields
-    audio_source_id: Optional[str] = Field(None, description="Parent multichannel audio source ID")
+    audio_source_id: Optional[str] = Field(None, description="Parent audio source ID")
     channel: Optional[str] = Field(None, description="Channel: mono|left|right")
+    # band_extract fields
+    band: Optional[str] = Field(None, description="Band preset: bass|mid|treble|custom")
+    freq_low: Optional[float] = Field(None, description="Low frequency bound (Hz)", ge=20, le=20000)
+    freq_high: Optional[float] = Field(None, description="High frequency bound (Hz)", ge=20, le=20000)
     description: Optional[str] = Field(None, description="Optional description", max_length=500)
     tags: List[str] = Field(default_factory=list, description="User-defined tags")
 
@@ -29,8 +33,11 @@ class AudioSourceUpdate(BaseModel):
     device_index: Optional[int] = Field(None, description="Audio device index (-1 = default)")
     is_loopback: Optional[bool] = Field(None, description="True for system audio (WASAPI loopback)")
     audio_template_id: Optional[str] = Field(None, description="Audio capture template ID")
-    audio_source_id: Optional[str] = Field(None, description="Parent multichannel audio source ID")
+    audio_source_id: Optional[str] = Field(None, description="Parent audio source ID")
     channel: Optional[str] = Field(None, description="Channel: mono|left|right")
+    band: Optional[str] = Field(None, description="Band preset: bass|mid|treble|custom")
+    freq_low: Optional[float] = Field(None, description="Low frequency bound (Hz)", ge=20, le=20000)
+    freq_high: Optional[float] = Field(None, description="High frequency bound (Hz)", ge=20, le=20000)
     description: Optional[str] = Field(None, description="Optional description", max_length=500)
     tags: Optional[List[str]] = None
 
@@ -40,12 +47,15 @@ class AudioSourceResponse(BaseModel):
 
     id: str = Field(description="Source ID")
     name: str = Field(description="Source name")
-    source_type: str = Field(description="Source type: multichannel or mono")
+    source_type: str = Field(description="Source type: multichannel, mono, or band_extract")
     device_index: Optional[int] = Field(None, description="Audio device index")
     is_loopback: Optional[bool] = Field(None, description="WASAPI loopback mode")
     audio_template_id: Optional[str] = Field(None, description="Audio capture template ID")
-    audio_source_id: Optional[str] = Field(None, description="Parent multichannel source ID")
+    audio_source_id: Optional[str] = Field(None, description="Parent audio source ID")
     channel: Optional[str] = Field(None, description="Channel: mono|left|right")
+    band: Optional[str] = Field(None, description="Band preset: bass|mid|treble|custom")
+    freq_low: Optional[float] = Field(None, description="Low frequency bound (Hz)")
+    freq_high: Optional[float] = Field(None, description="High frequency bound (Hz)")
     description: Optional[str] = Field(None, description="Description")
     tags: List[str] = Field(default_factory=list, description="User-defined tags")
     created_at: datetime = Field(description="Creation timestamp")

server/src/wled_controller/core/audio/band_filter.py

@@ -0,0 +1,63 @@
+"""Frequency band filtering for audio spectrum data.
+
+Computes masks that select specific frequency ranges from the 64-band
+log-spaced spectrum, and applies them to filter spectrum + RMS data.
+"""
+
+import math
+from typing import Tuple
+
+import numpy as np
+
+from wled_controller.core.audio.analysis import NUM_BANDS
+
+
+def compute_band_mask(freq_low: float, freq_high: float) -> np.ndarray:
+    """Compute a boolean-style float mask for the 64 log-spaced spectrum bands.
+
+    Each band's center frequency is computed using the same log-spacing as
+    analysis._build_log_bands (20 Hz to 20 kHz). Bands whose center falls
+    within [freq_low, freq_high] get mask=1.0, others get 0.0.
+
+    Returns:
+        float32 array of shape (NUM_BANDS,) with 1.0/0.0 values.
+    """
+    min_freq = 20.0
+    max_freq = 20000.0
+    log_min = math.log10(min_freq)
+    log_max = math.log10(max_freq)
+
+    # Band edge frequencies (NUM_BANDS + 1 edges)
+    edges = np.logspace(log_min, log_max, NUM_BANDS + 1)
+
+    mask = np.zeros(NUM_BANDS, dtype=np.float32)
+    for i in range(NUM_BANDS):
+        center = math.sqrt(edges[i] * edges[i + 1])  # geometric mean
+        if freq_low <= center <= freq_high:
+            mask[i] = 1.0
+    return mask
+
+
+def apply_band_filter(
+    spectrum: np.ndarray,
+    rms: float,
+    mask: np.ndarray,
+) -> Tuple[np.ndarray, float]:
+    """Apply a band mask to spectrum data, returning filtered spectrum and RMS.
+
+    Args:
+        spectrum: float32 array of shape (NUM_BANDS,) — normalized 0-1 amplitudes.
+        rms: Original RMS value from the full spectrum.
+        mask: float32 array from compute_band_mask().
+
+    Returns:
+        (filtered_spectrum, filtered_rms) — spectrum with out-of-band zeroed,
+        RMS recomputed from in-band values only.
+    """
+    filtered = spectrum * mask
+    active = mask > 0
+    if active.any():
+        filtered_rms = float(np.sqrt(np.mean(filtered[active] ** 2)))
+    else:
+        filtered_rms = 0.0
+    return filtered, filtered_rms

server/src/wled_controller/core/processing/audio_stream.py

@@ -17,6 +17,7 @@ import numpy as np
 
 from wled_controller.core.audio.analysis import NUM_BANDS
 from wled_controller.core.audio.audio_capture import AudioCaptureManager
+from wled_controller.core.audio.band_filter import apply_band_filter, compute_band_mask
 from wled_controller.core.processing.color_strip_stream import ColorStripStream
 from wled_controller.core.processing.effect_stream import _build_palette_lut
 from wled_controller.utils import get_logger
@@ -100,17 +101,18 @@ class AudioColorStripStream(ColorStripStream):
         self._audio_source_id = audio_source_id
         self._audio_engine_type = None
         self._audio_engine_config = None
+        self._band_mask = None  # precomputed band filter mask (None = full range)
         if audio_source_id and self._audio_source_store:
             try:
-                device_index, is_loopback, channel, template_id = (
-                    self._audio_source_store.resolve_audio_source(audio_source_id)
-                )
-                self._audio_device_index = device_index
-                self._audio_loopback = is_loopback
-                self._audio_channel = channel
-                if template_id and self._audio_template_store:
+                resolved = self._audio_source_store.resolve_audio_source(audio_source_id)
+                self._audio_device_index = resolved.device_index
+                self._audio_loopback = resolved.is_loopback
+                self._audio_channel = resolved.channel
+                if resolved.freq_low is not None and resolved.freq_high is not None:
+                    self._band_mask = compute_band_mask(resolved.freq_low, resolved.freq_high)
+                if resolved.audio_template_id and self._audio_template_store:
                     try:
-                        tpl = self._audio_template_store.get_template(template_id)
+                        tpl = self._audio_template_store.get_template(resolved.audio_template_id)
                         self._audio_engine_type = tpl.engine_type
                         self._audio_engine_config = tpl.engine_config
                     except ValueError:
@@ -320,12 +322,16 @@ class AudioColorStripStream(ColorStripStream):
     # ── Channel selection ─────────────────────────────────────────
 
     def _pick_channel(self, analysis):
-        """Return (spectrum, rms) for the configured audio channel."""
+        """Return (spectrum, rms) for the configured audio channel, with band filtering."""
         if self._audio_channel == "left":
-            return analysis.left_spectrum, analysis.left_rms
+            spectrum, rms = analysis.left_spectrum, analysis.left_rms
         elif self._audio_channel == "right":
-            return analysis.right_spectrum, analysis.right_rms
-        return analysis.spectrum, analysis.rms
+            spectrum, rms = analysis.right_spectrum, analysis.right_rms
+        else:
+            spectrum, rms = analysis.spectrum, analysis.rms
+        if self._band_mask is not None:
+            spectrum, rms = apply_band_filter(spectrum, rms, self._band_mask)
+        return spectrum, rms
 
     # ── Spectrum Analyzer ──────────────────────────────────────────
 

server/src/wled_controller/static/js/app.ts

@@ -148,7 +148,7 @@ import {
     showAudioSourceModal, closeAudioSourceModal, saveAudioSource,
     editAudioSource, cloneAudioSource, deleteAudioSource,
     testAudioSource, closeTestAudioSourceModal,
-    refreshAudioDevices,
+    refreshAudioDevices, onBandPresetChange,
 } from './features/audio-sources.ts';
 
 // Layer 5: value sources
@@ -474,6 +474,7 @@ Object.assign(window, {
     testAudioSource,
     closeTestAudioSourceModal,
     refreshAudioDevices,
+    onBandPresetChange,
 
     // value sources
     showValueSourceModal,

server/src/wled_controller/static/js/core/icons.ts

@@ -34,7 +34,7 @@ const _valueSourceTypeIcons   = {
     adaptive_time: _svg(P.clock), adaptive_scene: _svg(P.cloudSun),
     daylight: _svg(P.sun),
 };
-const _audioSourceTypeIcons   = { mono: _svg(P.mic), multichannel: _svg(P.volume2) };
+const _audioSourceTypeIcons   = { mono: _svg(P.mic), multichannel: _svg(P.volume2), band_extract: _svg(P.activity) };
 const _deviceTypeIcons        = {
     wled: _svg(P.wifi), adalight: _svg(P.usb), ambiled: _svg(P.usb),
     mqtt: _svg(P.send), ws: _svg(P.globe), openrgb: _svg(P.palette),

server/src/wled_controller/static/js/features/audio-sources.ts

@@ -1,10 +1,11 @@
 /**
- * Audio Sources — CRUD for multichannel and mono audio sources.
+ * Audio Sources — CRUD for multichannel, mono, and band extract audio sources.
  *
  * Audio sources are managed entities that encapsulate audio device
  * configuration. Multichannel sources represent physical audio devices;
- * mono sources extract a single channel from a multichannel source.
- * CSS audio type references a mono source by ID.
+ * mono sources extract a single channel from a multichannel source;
+ * band extract sources filter a parent source to a frequency band.
+ * CSS audio type references an audio source by ID.
  *
  * Card rendering is handled by streams.js (Audio tab).
  * This module manages the editor modal and API operations.
@@ -38,6 +39,10 @@ class AudioSourceModal extends Modal {
             audioTemplate: (document.getElementById('audio-source-audio-template') as HTMLSelectElement).value,
             parent: (document.getElementById('audio-source-parent') as HTMLSelectElement).value,
             channel: (document.getElementById('audio-source-channel') as HTMLSelectElement).value,
+            bandParent: (document.getElementById('audio-source-band-parent') as HTMLSelectElement).value,
+            band: (document.getElementById('audio-source-band') as HTMLSelectElement).value,
+            freqLow: (document.getElementById('audio-source-freq-low') as HTMLInputElement).value,
+            freqHigh: (document.getElementById('audio-source-freq-high') as HTMLInputElement).value,
             tags: JSON.stringify(_audioSourceTagsInput ? _audioSourceTagsInput.getValue() : []),
         };
     }
@@ -49,21 +54,27 @@ const audioSourceModal = new AudioSourceModal();
 let _asTemplateEntitySelect: EntitySelect | null = null;
 let _asDeviceEntitySelect: EntitySelect | null = null;
 let _asParentEntitySelect: EntitySelect | null = null;
+let _asBandParentEntitySelect: EntitySelect | null = null;
 
 // ── Modal ─────────────────────────────────────────────────────
 
+const _titleKeys: Record<string, Record<string, string>> = {
+    multichannel: { add: 'audio_source.add.multichannel', edit: 'audio_source.edit.multichannel' },
+    mono: { add: 'audio_source.add.mono', edit: 'audio_source.edit.mono' },
+    band_extract: { add: 'audio_source.add.band_extract', edit: 'audio_source.edit.band_extract' },
+};
+
 export async function showAudioSourceModal(sourceType: any, editData?: any) {
     const isEdit = !!editData;
-    const titleKey = isEdit
-        ? (editData.source_type === 'mono' ? 'audio_source.edit.mono' : 'audio_source.edit.multichannel')
-        : (sourceType === 'mono' ? 'audio_source.add.mono' : 'audio_source.add.multichannel');
+    const st = isEdit ? editData.source_type : sourceType;
+    const titleKey = _titleKeys[st]?.[isEdit ? 'edit' : 'add'] || _titleKeys.multichannel.add;
 
     document.getElementById('audio-source-modal-title')!.innerHTML = `${ICON_MUSIC} ${t(titleKey)}`;
     (document.getElementById('audio-source-id') as HTMLInputElement).value = isEdit ? editData.id : '';
     (document.getElementById('audio-source-error') as HTMLElement).style.display = 'none';
 
     const typeSelect = document.getElementById('audio-source-type') as HTMLSelectElement;
-    typeSelect.value = isEdit ? editData.source_type : sourceType;
+    typeSelect.value = st;
     typeSelect.disabled = isEdit; // can't change type after creation
 
     onAudioSourceTypeChange();
@@ -77,9 +88,15 @@ export async function showAudioSourceModal(sourceType: any, editData?: any) {
             (document.getElementById('audio-source-audio-template') as HTMLSelectElement).onchange = _filterDevicesBySelectedTemplate;
             await _loadAudioDevices();
             _selectAudioDevice(editData.device_index, editData.is_loopback);
-        } else {
+        } else if (editData.source_type === 'mono') {
             _loadMultichannelSources(editData.audio_source_id);
             (document.getElementById('audio-source-channel') as HTMLSelectElement).value = editData.channel || 'mono';
+        } else if (editData.source_type === 'band_extract') {
+            _loadBandParentSources(editData.audio_source_id);
+            (document.getElementById('audio-source-band') as HTMLSelectElement).value = editData.band || 'bass';
+            (document.getElementById('audio-source-freq-low') as HTMLInputElement).value = String(editData.freq_low ?? 20);
+            (document.getElementById('audio-source-freq-high') as HTMLInputElement).value = String(editData.freq_high ?? 20000);
+            onBandPresetChange();
         }
     } else {
         (document.getElementById('audio-source-name') as HTMLInputElement).value = '';
@@ -89,8 +106,14 @@ export async function showAudioSourceModal(sourceType: any, editData?: any) {
             _loadAudioTemplates();
             (document.getElementById('audio-source-audio-template') as HTMLSelectElement).onchange = _filterDevicesBySelectedTemplate;
             await _loadAudioDevices();
-        } else {
+        } else if (sourceType === 'mono') {
             _loadMultichannelSources();
+        } else if (sourceType === 'band_extract') {
+            _loadBandParentSources();
+            (document.getElementById('audio-source-band') as HTMLSelectElement).value = 'bass';
+            (document.getElementById('audio-source-freq-low') as HTMLInputElement).value = '20';
+            (document.getElementById('audio-source-freq-high') as HTMLInputElement).value = '20000';
+            onBandPresetChange();
         }
     }
 
@@ -111,6 +134,12 @@ export function onAudioSourceTypeChange() {
     const type = (document.getElementById('audio-source-type') as HTMLSelectElement).value;
     (document.getElementById('audio-source-multichannel-section') as HTMLElement).style.display = type === 'multichannel' ? '' : 'none';
     (document.getElementById('audio-source-mono-section') as HTMLElement).style.display = type === 'mono' ? '' : 'none';
+    (document.getElementById('audio-source-band-extract-section') as HTMLElement).style.display = type === 'band_extract' ? '' : 'none';
+}
+
+export function onBandPresetChange() {
+    const band = (document.getElementById('audio-source-band') as HTMLSelectElement).value;
+    (document.getElementById('audio-source-custom-freq') as HTMLElement).style.display = band === 'custom' ? '' : 'none';
 }
 
 // ── Save ──────────────────────────────────────────────────────
@@ -136,9 +165,16 @@ export async function saveAudioSource() {
         payload.device_index = parseInt(devIdx) || -1;
         payload.is_loopback = devLoop !== '0';
         payload.audio_template_id = (document.getElementById('audio-source-audio-template') as HTMLSelectElement).value || null;
-    } else {
+    } else if (sourceType === 'mono') {
         payload.audio_source_id = (document.getElementById('audio-source-parent') as HTMLSelectElement).value;
         payload.channel = (document.getElementById('audio-source-channel') as HTMLSelectElement).value;
+    } else if (sourceType === 'band_extract') {
+        payload.audio_source_id = (document.getElementById('audio-source-band-parent') as HTMLSelectElement).value;
+        payload.band = (document.getElementById('audio-source-band') as HTMLSelectElement).value;
+        if (payload.band === 'custom') {
+            payload.freq_low = parseFloat((document.getElementById('audio-source-freq-low') as HTMLInputElement).value) || 20;
+            payload.freq_high = parseFloat((document.getElementById('audio-source-freq-high') as HTMLInputElement).value) || 20000;
+        }
     }
 
     try {
@@ -321,6 +357,30 @@ function _loadMultichannelSources(selectedId?: any) {
     }
 }
 
+function _loadBandParentSources(selectedId?: any) {
+    const select = document.getElementById('audio-source-band-parent') as HTMLSelectElement | null;
+    if (!select) return;
+    // Band extract can reference any audio source type
+    const sources = _cachedAudioSources;
+    select.innerHTML = sources.map(s =>
+        `<option value="${s.id}"${s.id === selectedId ? ' selected' : ''}>${escapeHtml(s.name)}</option>`
+    ).join('');
+
+    if (_asBandParentEntitySelect) _asBandParentEntitySelect.destroy();
+    if (sources.length > 0) {
+        _asBandParentEntitySelect = new EntitySelect({
+            target: select,
+            getItems: () => sources.map((s: any) => ({
+                value: s.id,
+                label: s.name,
+                icon: getAudioSourceIcon(s.source_type),
+                desc: s.source_type,
+            })),
+            placeholder: t('palette.search'),
+        } as any);
+    }
+}
+
 function _loadAudioTemplates(selectedId?: any) {
     const select = document.getElementById('audio-source-audio-template') as HTMLSelectElement | null;
     if (!select) return;
@@ -469,7 +529,7 @@ export function initAudioSourceDelegation(container: HTMLElement): void {
         const handler = _audioSourceActions[action];
         if (handler) {
             // Verify we're inside an audio source section
-            const section = btn.closest<HTMLElement>('[data-card-section="audio-multi"], [data-card-section="audio-mono"]');
+            const section = btn.closest<HTMLElement>('[data-card-section="audio-multi"], [data-card-section="audio-mono"], [data-card-section="audio-band-extract"]');
             if (!section) return;
             const card = btn.closest<HTMLElement>('[data-id]');
             const id = card?.getAttribute('data-id');

server/src/wled_controller/static/js/features/color-strips.ts

@@ -875,7 +875,7 @@ async function _loadAudioSources() {
     try {
         const sources: any[] = await audioSourcesCache.fetch();
         select.innerHTML = sources.map(s => {
-            const badge = s.source_type === 'multichannel' ? ' [multichannel]' : ' [mono]';
+            const badge = s.source_type === 'multichannel' ? ' [multichannel]' : s.source_type === 'band_extract' ? ' [band]' : ' [mono]';
             return `<option value="${s.id}">${escapeHtml(s.name)}${badge}</option>`;
         }).join('');
         if (sources.length === 0) {

server/src/wled_controller/static/js/features/streams.ts

@@ -57,7 +57,7 @@ import {
     getEngineIcon, getAudioEngineIcon, getPictureSourceIcon, getAudioSourceIcon, getColorStripIcon,
     ICON_TEMPLATE, ICON_CLONE, ICON_EDIT, ICON_TEST, ICON_LINK_SOURCE,
     ICON_FPS, ICON_WEB, ICON_VALUE_SOURCE, ICON_CLOCK, ICON_AUDIO_LOOPBACK, ICON_AUDIO_INPUT,
-    ICON_AUDIO_TEMPLATE, ICON_MONITOR, ICON_WRENCH, ICON_RADIO,
+    ICON_AUDIO_TEMPLATE, ICON_MONITOR, ICON_WRENCH, ICON_RADIO, ICON_ACTIVITY,
     ICON_CAPTURE_TEMPLATE, ICON_PP_TEMPLATE, ICON_CSPT, ICON_HELP, ICON_TRASH, ICON_PALETTE,
 } from '../core/icons.ts';
 import * as P from '../core/icon-paths.ts';
@@ -106,6 +106,7 @@ const csProcStreams = new CardSection('proc-streams', { titleKey: 'streams.secti
 const csProcTemplates = new CardSection('proc-templates', { titleKey: 'postprocessing.title', gridClass: 'templates-grid', addCardOnclick: "showAddPPTemplateModal()", keyAttr: 'data-pp-template-id', emptyKey: 'section.empty.pp_templates', bulkActions: _ppTemplateDeleteAction });
 const csAudioMulti = new CardSection('audio-multi', { titleKey: 'audio_source.group.multichannel', gridClass: 'templates-grid', addCardOnclick: "showAudioSourceModal('multichannel')", keyAttr: 'data-id', emptyKey: 'section.empty.audio_sources', bulkActions: _audioSourceDeleteAction });
 const csAudioMono = new CardSection('audio-mono', { titleKey: 'audio_source.group.mono', gridClass: 'templates-grid', addCardOnclick: "showAudioSourceModal('mono')", keyAttr: 'data-id', emptyKey: 'section.empty.audio_sources', bulkActions: _audioSourceDeleteAction });
+const csAudioBandExtract = new CardSection('audio-band-extract', { titleKey: 'audio_source.group.band_extract', gridClass: 'templates-grid', addCardOnclick: "showAudioSourceModal('band_extract')", keyAttr: 'data-id', emptyKey: 'section.empty.audio_sources', bulkActions: _audioSourceDeleteAction });
 const csStaticStreams = new CardSection('static-streams', { titleKey: 'streams.group.static_image', gridClass: 'templates-grid', addCardOnclick: "showAddStreamModal('static_image')", keyAttr: 'data-stream-id', emptyKey: 'section.empty.picture_sources', bulkActions: _streamDeleteAction });
 const csVideoStreams = new CardSection('video-streams', { titleKey: 'streams.group.video', gridClass: 'templates-grid', addCardOnclick: "showAddStreamModal('video')", keyAttr: 'data-stream-id', emptyKey: 'section.empty.picture_sources', bulkActions: _streamDeleteAction });
 const csAudioTemplates = new CardSection('audio-templates', { titleKey: 'audio_template.title', gridClass: 'templates-grid', addCardOnclick: "showAddAudioTemplateModal()", keyAttr: 'data-audio-template-id', emptyKey: 'section.empty.audio_templates', bulkActions: _audioTemplateDeleteAction });
@@ -275,7 +276,7 @@ const _streamSectionMap = {
     proc_templates: [csProcTemplates],
     css_processing: [csCSPTemplates],
     color_strip: [csColorStrips],
-    audio: [csAudioMulti, csAudioMono],
+    audio: [csAudioMulti, csAudioMono, csAudioBandExtract],
     audio_templates: [csAudioTemplates],
     value: [csValueSources],
     sync: [csSyncClocks],
@@ -462,6 +463,7 @@ function renderPictureSourcesList(streams: any) {
 
     const multichannelSources = _cachedAudioSources.filter(s => s.source_type === 'multichannel');
     const monoSources = _cachedAudioSources.filter(s => s.source_type === 'mono');
+    const bandExtractSources = _cachedAudioSources.filter(s => s.source_type === 'band_extract');
 
     // CSPT templates
     const csptTemplates = csptCache.data;
@@ -545,12 +547,19 @@ function renderPictureSourcesList(streams: any) {
         }
     ];
 
+    const _bandLabels: Record<string, string> = { bass: 'Bass', mid: 'Mid', treble: 'Treble', custom: 'Custom' };
+
+    const _getSectionForSource = (sourceType: string): string => {
+        if (sourceType === 'multichannel') return 'audio-multi';
+        if (sourceType === 'mono') return 'audio-mono';
+        return 'audio-band-extract';
+    };
+
     const renderAudioSourceCard = (src: any) => {
-        const isMono = src.source_type === 'mono';
         const icon = getAudioSourceIcon(src.source_type);
 
         let propsHtml = '';
-        if (isMono) {
+        if (src.source_type === 'mono') {
             const parent = _cachedAudioSources.find(s => s.id === src.audio_source_id);
             const parentName = parent ? parent.name : src.audio_source_id;
             const chLabel = src.channel === 'left' ? 'L' : src.channel === 'right' ? 'R' : 'M';
@@ -561,6 +570,20 @@ function renderPictureSourcesList(streams: any) {
                 ${parentBadge}
                 <span class="stream-card-prop" title="${escapeHtml(t('audio_source.channel'))}">${ICON_RADIO} ${chLabel}</span>
             `;
+        } else if (src.source_type === 'band_extract') {
+            const parent = _cachedAudioSources.find(s => s.id === src.audio_source_id);
+            const parentName = parent ? parent.name : src.audio_source_id;
+            const parentSection = parent ? _getSectionForSource(parent.source_type) : 'audio-multi';
+            const parentBadge = parent
+                ? `<span class="stream-card-prop stream-card-link" title="${escapeHtml(t('audio_source.band_parent'))}" onclick="event.stopPropagation(); navigateToCard('streams','audio','${parentSection}','data-id','${src.audio_source_id}')">${getAudioSourceIcon(parent.source_type)} ${escapeHtml(parentName)}</span>`
+                : `<span class="stream-card-prop" title="${escapeHtml(t('audio_source.band_parent'))}">${ICON_ACTIVITY} ${escapeHtml(parentName)}</span>`;
+            const bandLabel = _bandLabels[src.band] || src.band;
+            const freqRange = `${Math.round(src.freq_low)}–${Math.round(src.freq_high)} Hz`;
+            propsHtml = `
+                ${parentBadge}
+                <span class="stream-card-prop" title="${escapeHtml(t('audio_source.band'))}">${ICON_ACTIVITY} ${bandLabel}</span>
+                <span class="stream-card-prop" title="${escapeHtml(t('audio_source.freq_range'))}">${freqRange}</span>
+            `;
         } else {
             const devIdx = src.device_index ?? -1;
             const loopback = src.is_loopback !== false;
@@ -664,6 +687,7 @@ function renderPictureSourcesList(streams: any) {
     const procTemplateItems = csProcTemplates.applySortOrder(_cachedPPTemplates.map(t => ({ key: t.id, html: renderPPTemplateCard(t) })));
     const multiItems = csAudioMulti.applySortOrder(multichannelSources.map(s => ({ key: s.id, html: renderAudioSourceCard(s) })));
     const monoItems = csAudioMono.applySortOrder(monoSources.map(s => ({ key: s.id, html: renderAudioSourceCard(s) })));
+    const bandExtractItems = csAudioBandExtract.applySortOrder(bandExtractSources.map(s => ({ key: s.id, html: renderAudioSourceCard(s) })));
     const audioTemplateItems = csAudioTemplates.applySortOrder(_cachedAudioTemplates.map(t => ({ key: t.id, html: renderAudioTemplateCard(t) })));
     const staticItems = csStaticStreams.applySortOrder(staticImageStreams.map(s => ({ key: s.id, html: renderStreamCard(s) })));
     const videoItems = csVideoStreams.applySortOrder(videoStreams.map(s => ({ key: s.id, html: renderStreamCard(s) })));
@@ -701,6 +725,7 @@ function renderPictureSourcesList(streams: any) {
         csGradients.reconcile(gradientItems);
         csAudioMulti.reconcile(multiItems);
         csAudioMono.reconcile(monoItems);
+        csAudioBandExtract.reconcile(bandExtractItems);
         csAudioTemplates.reconcile(audioTemplateItems);
         csStaticStreams.reconcile(staticItems);
         csVideoStreams.reconcile(videoItems);
@@ -718,7 +743,7 @@ function renderPictureSourcesList(streams: any) {
             else if (tab.key === 'css_processing') panelContent = csCSPTemplates.render(csptItems);
             else if (tab.key === 'color_strip') panelContent = csColorStrips.render(colorStripItems);
             else if (tab.key === 'gradients') panelContent = csGradients.render(gradientItems);
-            else if (tab.key === 'audio') panelContent = csAudioMulti.render(multiItems) + csAudioMono.render(monoItems);
+            else if (tab.key === 'audio') panelContent = csAudioMulti.render(multiItems) + csAudioMono.render(monoItems) + csAudioBandExtract.render(bandExtractItems);
             else if (tab.key === 'audio_templates') panelContent = csAudioTemplates.render(audioTemplateItems);
             else if (tab.key === 'value') panelContent = csValueSources.render(valueItems);
             else if (tab.key === 'sync') panelContent = csSyncClocks.render(syncClockItems);
@@ -729,7 +754,7 @@ function renderPictureSourcesList(streams: any) {
         }).join('');
 
         container.innerHTML = panels;
-        CardSection.bindAll([csRawStreams, csRawTemplates, csProcStreams, csProcTemplates, csCSPTemplates, csColorStrips, csGradients, csAudioMulti, csAudioMono, csAudioTemplates, csStaticStreams, csVideoStreams, csValueSources, csSyncClocks, csWeatherSources]);
+        CardSection.bindAll([csRawStreams, csRawTemplates, csProcStreams, csProcTemplates, csCSPTemplates, csColorStrips, csGradients, csAudioMulti, csAudioMono, csAudioBandExtract, csAudioTemplates, csStaticStreams, csVideoStreams, csValueSources, csSyncClocks, csWeatherSources]);
 
         // Event delegation for card actions (replaces inline onclick handlers)
         initSyncClockDelegation(container);
@@ -747,7 +772,7 @@ function renderPictureSourcesList(streams: any) {
             'css-proc-templates': 'css_processing',
             'color-strips': 'color_strip',
             'gradients': 'gradients',
-            'audio-multi': 'audio', 'audio-mono': 'audio',
+            'audio-multi': 'audio', 'audio-mono': 'audio', 'audio-band-extract': 'audio',
             'audio-templates': 'audio_templates',
             'value-sources': 'value',
             'sync-clocks': 'sync',

server/src/wled_controller/static/js/features/value-sources.ts

@@ -835,7 +835,7 @@ function _populateAudioSourceDropdown(selectedId: any) {
     const select = document.getElementById('value-source-audio-source') as HTMLSelectElement;
     if (!select) return;
     select.innerHTML = _cachedAudioSources.map((s: any) => {
-        const badge = s.source_type === 'multichannel' ? ' [multichannel]' : ' [mono]';
+        const badge = s.source_type === 'multichannel' ? ' [multichannel]' : s.source_type === 'band_extract' ? ' [band]' : ' [mono]';
         return `<option value="${s.id}"${s.id === selectedId ? ' selected' : ''}>${escapeHtml(s.name)}${badge}</option>`;
     }).join('');
 

server/src/wled_controller/static/js/types.ts

@@ -300,7 +300,7 @@ export interface ValueSource {
 export interface AudioSource {
     id: string;
     name: string;
-    source_type: 'multichannel' | 'mono';
+    source_type: 'multichannel' | 'mono' | 'band_extract';
     description?: string;
     tags: string[];
     created_at: string;
@@ -314,6 +314,11 @@ export interface AudioSource {
     // Mono
     audio_source_id?: string;
     channel?: string;
+
+    // Band Extract
+    band?: string;
+    freq_low?: number;
+    freq_high?: number;
 }
 
 // ── Picture Source ─────────────────────────────────────────────

server/src/wled_controller/static/locales/en.json

@@ -1300,12 +1300,15 @@
     "audio_source.title": "Audio Sources",
     "audio_source.group.multichannel": "Multichannel",
     "audio_source.group.mono": "Mono",
+    "audio_source.group.band_extract": "Band Extract",
     "audio_source.add": "Add Audio Source",
     "audio_source.add.multichannel": "Add Multichannel Source",
     "audio_source.add.mono": "Add Mono Source",
+    "audio_source.add.band_extract": "Add Band Extract Source",
     "audio_source.edit": "Edit Audio Source",
     "audio_source.edit.multichannel": "Edit Multichannel Source",
     "audio_source.edit.mono": "Edit Mono Source",
+    "audio_source.edit.band_extract": "Edit Band Extract Source",
     "audio_source.name": "Name:",
     "audio_source.name.placeholder": "System Audio",
     "audio_source.name.hint": "A descriptive name for this audio source",
@@ -1333,6 +1336,17 @@
     "audio_source.error.name_required": "Please enter a name",
     "audio_source.audio_template": "Audio Template:",
     "audio_source.audio_template.hint": "Audio capture template that defines which engine and settings to use for this device",
+    "audio_source.band_parent": "Parent Audio Source:",
+    "audio_source.band_parent.hint": "Audio source to extract the frequency band from",
+    "audio_source.band": "Frequency Band:",
+    "audio_source.band.hint": "Select a frequency band preset or custom range",
+    "audio_source.band.bass": "Bass (20–250 Hz)",
+    "audio_source.band.mid": "Mid (250–4000 Hz)",
+    "audio_source.band.treble": "Treble (4000–20000 Hz)",
+    "audio_source.band.custom": "Custom Range",
+    "audio_source.freq_low": "Low Frequency (Hz):",
+    "audio_source.freq_high": "High Frequency (Hz):",
+    "audio_source.freq_range": "Frequency Range",
     "audio_source.test": "Test",
     "audio_source.test.title": "Test Audio Source",
     "audio_source.test.rms": "RMS",

server/src/wled_controller/static/locales/ru.json

@@ -1248,12 +1248,15 @@
     "audio_source.title": "Аудиоисточники",
     "audio_source.group.multichannel": "Многоканальные",
     "audio_source.group.mono": "Моно",
+    "audio_source.group.band_extract": "Полосовой фильтр",
     "audio_source.add": "Добавить аудиоисточник",
     "audio_source.add.multichannel": "Добавить многоканальный",
     "audio_source.add.mono": "Добавить моно",
+    "audio_source.add.band_extract": "Добавить полосовой фильтр",
     "audio_source.edit": "Редактировать аудиоисточник",
     "audio_source.edit.multichannel": "Редактировать многоканальный",
     "audio_source.edit.mono": "Редактировать моно",
+    "audio_source.edit.band_extract": "Редактировать полосовой фильтр",
     "audio_source.name": "Название:",
     "audio_source.name.placeholder": "Системный звук",
     "audio_source.name.hint": "Описательное имя для этого аудиоисточника",
@@ -1281,6 +1284,17 @@
     "audio_source.error.name_required": "Введите название",
     "audio_source.audio_template": "Аудиошаблон:",
     "audio_source.audio_template.hint": "Шаблон аудиозахвата определяет, какой движок и настройки использовать для этого устройства",
+    "audio_source.band_parent": "Родительский аудиоисточник:",
+    "audio_source.band_parent.hint": "Аудиоисточник для извлечения частотной полосы",
+    "audio_source.band": "Частотная полоса:",
+    "audio_source.band.hint": "Выберите предустановку частотной полосы или произвольный диапазон",
+    "audio_source.band.bass": "Басы (20–250 Гц)",
+    "audio_source.band.mid": "Средние (250–4000 Гц)",
+    "audio_source.band.treble": "Высокие (4000–20000 Гц)",
+    "audio_source.band.custom": "Произвольный диапазон",
+    "audio_source.freq_low": "Нижняя частота (Гц):",
+    "audio_source.freq_high": "Верхняя частота (Гц):",
+    "audio_source.freq_range": "Частотный диапазон",
     "audio_source.test": "Тест",
     "audio_source.test.title": "Тест аудиоисточника",
     "audio_source.test.rms": "RMS",

server/src/wled_controller/static/locales/zh.json

@@ -1248,12 +1248,15 @@
     "audio_source.title": "音频源",
     "audio_source.group.multichannel": "多声道",
     "audio_source.group.mono": "单声道",
+    "audio_source.group.band_extract": "频段提取",
     "audio_source.add": "添加音频源",
     "audio_source.add.multichannel": "添加多声道源",
     "audio_source.add.mono": "添加单声道源",
+    "audio_source.add.band_extract": "添加频段提取源",
     "audio_source.edit": "编辑音频源",
     "audio_source.edit.multichannel": "编辑多声道源",
     "audio_source.edit.mono": "编辑单声道源",
+    "audio_source.edit.band_extract": "编辑频段提取源",
     "audio_source.name": "名称：",
     "audio_source.name.placeholder": "系统音频",
     "audio_source.name.hint": "此音频源的描述性名称",
@@ -1281,6 +1284,17 @@
     "audio_source.error.name_required": "请输入名称",
     "audio_source.audio_template": "音频模板：",
     "audio_source.audio_template.hint": "定义此设备使用哪个引擎和设置的音频采集模板",
+    "audio_source.band_parent": "父音频源：",
+    "audio_source.band_parent.hint": "要从中提取频段的音频源",
+    "audio_source.band": "频段：",
+    "audio_source.band.hint": "选择频段预设或自定义范围",
+    "audio_source.band.bass": "低音 (20–250 Hz)",
+    "audio_source.band.mid": "中音 (250–4000 Hz)",
+    "audio_source.band.treble": "高音 (4000–20000 Hz)",
+    "audio_source.band.custom": "自定义范围",
+    "audio_source.freq_low": "低频 (Hz)：",
+    "audio_source.freq_high": "高频 (Hz)：",
+    "audio_source.freq_range": "频率范围",
     "audio_source.test": "测试",
     "audio_source.test.title": "测试音频源",
     "audio_source.test.rms": "RMS",

server/src/wled_controller/storage/audio_source.py

@@ -3,11 +3,19 @@
 An AudioSource represents a reusable audio input configuration:
   MultichannelAudioSource   — wraps a physical audio device (index + loopback flag)
   MonoAudioSource           — extracts a single channel from a multichannel source
+  BandExtractAudioSource    — filters a parent source to a frequency band (bass/mid/treble/custom)
 """
 
 from dataclasses import dataclass, field
 from datetime import datetime, timezone
-from typing import List, Optional
+from typing import Dict, List, Optional, Tuple
+
+# Frequency band presets: band name → (freq_low_hz, freq_high_hz)
+BAND_PRESETS: Dict[str, Tuple[float, float]] = {
+    "bass": (20.0, 250.0),
+    "mid": (250.0, 4000.0),
+    "treble": (4000.0, 20000.0),
+}
 
 
 @dataclass
@@ -16,7 +24,7 @@ class AudioSource:
 
     id: str
     name: str
-    source_type: str  # "multichannel" | "mono"
+    source_type: str  # "multichannel" | "mono" | "band_extract"
     created_at: datetime
     updated_at: datetime
     description: Optional[str] = None
@@ -38,6 +46,9 @@ class AudioSource:
             "audio_template_id": None,
             "audio_source_id": None,
             "channel": None,
+            "band": None,
+            "freq_low": None,
+            "freq_high": None,
         }
 
     @staticmethod
@@ -72,6 +83,22 @@ class AudioSource:
                 channel=data.get("channel") or "mono",
             )
 
+        if source_type == "band_extract":
+            band = data.get("band") or "bass"
+            if band in BAND_PRESETS:
+                freq_low, freq_high = BAND_PRESETS[band]
+            else:
+                freq_low = float(data.get("freq_low") or 20.0)
+                freq_high = float(data.get("freq_high") or 20000.0)
+            return BandExtractAudioSource(
+                id=sid, name=name, source_type="band_extract",
+                created_at=created_at, updated_at=updated_at, description=description, tags=tags,
+                audio_source_id=data.get("audio_source_id") or "",
+                band=band,
+                freq_low=freq_low,
+                freq_high=freq_high,
+            )
+
         # Default: multichannel
         return MultichannelAudioSource(
             id=sid, name=name, source_type="multichannel",
@@ -118,3 +145,26 @@ class MonoAudioSource(AudioSource):
         d["audio_source_id"] = self.audio_source_id
         d["channel"] = self.channel
         return d
+
+
+@dataclass
+class BandExtractAudioSource(AudioSource):
+    """Audio source that filters a parent source to a specific frequency band.
+
+    References any AudioSource and extracts only the specified frequency range.
+    Preset bands: bass (20-250 Hz), mid (250-4000 Hz), treble (4000-20000 Hz).
+    Custom band allows user-specified freq_low/freq_high.
+    """
+
+    audio_source_id: str = ""   # references any AudioSource
+    band: str = "bass"          # bass | mid | treble | custom
+    freq_low: float = 20.0      # lower frequency bound (Hz)
+    freq_high: float = 250.0    # upper frequency bound (Hz)
+
+    def to_dict(self) -> dict:
+        d = super().to_dict()
+        d["audio_source_id"] = self.audio_source_id
+        d["band"] = self.band
+        d["freq_low"] = self.freq_low
+        d["freq_high"] = self.freq_high
+        return d

server/src/wled_controller/storage/audio_source_store.py

@@ -2,10 +2,12 @@
 
 import uuid
 from datetime import datetime, timezone
-from typing import List, Optional, Tuple
+from typing import List, NamedTuple, Optional, Set
 
 from wled_controller.storage.audio_source import (
+    BAND_PRESETS,
     AudioSource,
+    BandExtractAudioSource,
     MonoAudioSource,
     MultichannelAudioSource,
 )
@@ -16,6 +18,17 @@ from wled_controller.utils import get_logger
 logger = get_logger(__name__)
 
 
+class ResolvedAudioSource(NamedTuple):
+    """Result of resolving an audio source to its physical device + band info."""
+
+    device_index: int
+    is_loopback: bool
+    channel: str
+    audio_template_id: Optional[str]
+    freq_low: Optional[float] = None   # None = full range (no band filtering)
+    freq_high: Optional[float] = None
+
+
 class AudioSourceStore(BaseJsonStore[AudioSource]):
     """Persistent storage for audio sources."""
 
@@ -44,10 +57,13 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
         description: Optional[str] = None,
         audio_template_id: Optional[str] = None,
         tags: Optional[List[str]] = None,
+        band: Optional[str] = None,
+        freq_low: Optional[float] = None,
+        freq_high: Optional[float] = None,
     ) -> AudioSource:
         self._check_name_unique(name)
 
-        if source_type not in ("multichannel", "mono"):
+        if source_type not in ("multichannel", "mono", "band_extract"):
             raise ValueError(f"Invalid source type: {source_type}")
 
         sid = f"as_{uuid.uuid4().hex[:8]}"
@@ -63,12 +79,28 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
             if not isinstance(parent, MultichannelAudioSource):
                 raise ValueError("Mono sources must reference a multichannel source")
 
-            source = MonoAudioSource(
+            source: AudioSource = MonoAudioSource(
                 id=sid, name=name, source_type="mono",
                 created_at=now, updated_at=now, description=description, tags=tags or [],
                 audio_source_id=audio_source_id,
                 channel=channel or "mono",
             )
+        elif source_type == "band_extract":
+            if not audio_source_id:
+                raise ValueError("Band extract sources require audio_source_id")
+            parent = self._items.get(audio_source_id)
+            if not parent:
+                raise ValueError(f"Parent audio source not found: {audio_source_id}")
+
+            band_val = band or "bass"
+            fl, fh = _resolve_band_freqs(band_val, freq_low, freq_high)
+
+            source = BandExtractAudioSource(
+                id=sid, name=name, source_type="band_extract",
+                created_at=now, updated_at=now, description=description, tags=tags or [],
+                audio_source_id=audio_source_id,
+                band=band_val, freq_low=fl, freq_high=fh,
+            )
         else:
             source = MultichannelAudioSource(
                 id=sid, name=name, source_type="multichannel",
@@ -95,6 +127,9 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
         description: Optional[str] = None,
         audio_template_id: Optional[str] = None,
         tags: Optional[List[str]] = None,
+        band: Optional[str] = None,
+        freq_low: Optional[float] = None,
+        freq_high: Optional[float] = None,
     ) -> AudioSource:
         source = self.get(source_id)
 
@@ -127,6 +162,27 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
                 source.audio_source_id = resolved
             if channel is not None:
                 source.channel = channel
+        elif isinstance(source, BandExtractAudioSource):
+            if audio_source_id is not None:
+                resolved = resolve_ref(audio_source_id, source.audio_source_id)
+                if resolved is not None:
+                    parent = self._items.get(resolved)
+                    if not parent:
+                        raise ValueError(f"Parent audio source not found: {resolved}")
+                    # Check for cycles
+                    self._check_no_cycle(source_id, resolved)
+                source.audio_source_id = resolved
+            if band is not None:
+                fl, fh = _resolve_band_freqs(band, freq_low, freq_high)
+                source.band = band
+                source.freq_low = fl
+                source.freq_high = fh
+            elif freq_low is not None or freq_high is not None:
+                # Update custom freq range without changing band preset
+                if freq_low is not None:
+                    source.freq_low = freq_low
+                if freq_high is not None:
+                    source.freq_high = freq_high
 
         source.updated_at = datetime.now(timezone.utc)
         self._save()
@@ -140,12 +196,14 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
 
         source = self._items[source_id]
 
-        # Prevent deleting multichannel sources referenced by mono sources
-        if isinstance(source, MultichannelAudioSource):
+        # Prevent deleting sources referenced by children (mono or band_extract)
         for other in self._items.values():
-                if isinstance(other, MonoAudioSource) and other.audio_source_id == source_id:
+            if other.id == source_id:
+                continue
+            parent_ref = getattr(other, "audio_source_id", None)
+            if parent_ref == source_id:
                 raise ValueError(
-                        f"Cannot delete '{source.name}': referenced by mono source '{other.name}'"
+                    f"Cannot delete '{source.name}': referenced by {other.source_type} source '{other.name}'"
                 )
 
         del self._items[source_id]
@@ -155,19 +213,28 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
 
     # ── Resolution ───────────────────────────────────────────────────
 
-    def resolve_audio_source(self, source_id: str) -> Tuple[int, bool, str, Optional[str]]:
-        """Resolve any audio source to (device_index, is_loopback, channel, audio_template_id).
+    def resolve_audio_source(self, source_id: str) -> ResolvedAudioSource:
+        """Resolve any audio source to its physical device, channel, and band info.
 
-        Accepts both MultichannelAudioSource (defaults to "mono" channel)
-        and MonoAudioSource (follows reference chain to parent multichannel).
+        Follows the reference chain: band_extract → mono/multichannel → device.
+        For band_extract sources, intersects frequency ranges when chained.
 
         Raises:
-            ValueError: If source not found or chain is broken
+            ValueError: If source not found, chain is broken, or cycle detected
         """
+        return self._resolve(source_id, visited=set())
+
+    def _resolve(self, source_id: str, visited: Set[str]) -> ResolvedAudioSource:
+        if source_id in visited:
+            raise ValueError(f"Cycle detected in audio source chain: {source_id}")
+        visited.add(source_id)
+
         source = self.get_source(source_id)
 
         if isinstance(source, MultichannelAudioSource):
-            return source.device_index, source.is_loopback, "mono", source.audio_template_id
+            return ResolvedAudioSource(
+                source.device_index, source.is_loopback, "mono", source.audio_template_id,
+            )
 
         if isinstance(source, MonoAudioSource):
             parent = self.get_source(source.audio_source_id)
@@ -175,6 +242,59 @@ class AudioSourceStore(BaseJsonStore[AudioSource]):
                 raise ValueError(
                     f"Mono source {source_id} references non-multichannel source {source.audio_source_id}"
                 )
-            return parent.device_index, parent.is_loopback, source.channel, parent.audio_template_id
+            return ResolvedAudioSource(
+                parent.device_index, parent.is_loopback, source.channel, parent.audio_template_id,
+            )
+
+        if isinstance(source, BandExtractAudioSource):
+            parent_resolved = self._resolve(source.audio_source_id, visited)
+            # Intersect frequency ranges if parent also has band filtering
+            fl = source.freq_low
+            fh = source.freq_high
+            if parent_resolved.freq_low is not None:
+                fl = max(fl, parent_resolved.freq_low)
+            if parent_resolved.freq_high is not None:
+                fh = min(fh, parent_resolved.freq_high)
+            if fl >= fh:
+                raise ValueError(
+                    f"Band extract '{source.name}' has empty frequency intersection: {fl}-{fh} Hz"
+                )
+            return ResolvedAudioSource(
+                parent_resolved.device_index,
+                parent_resolved.is_loopback,
+                parent_resolved.channel,
+                parent_resolved.audio_template_id,
+                fl, fh,
+            )
 
         raise ValueError(f"Audio source {source_id} is not a valid audio source")
+
+    def _check_no_cycle(self, source_id: str, new_parent_id: str) -> None:
+        """Ensure setting new_parent_id as parent of source_id won't create a cycle."""
+        visited: Set[str] = {source_id}
+        current = new_parent_id
+        while current:
+            if current in visited:
+                raise ValueError("Cannot set parent: would create a circular reference")
+            visited.add(current)
+            item = self._items.get(current)
+            if item is None:
+                break
+            current = getattr(item, "audio_source_id", None)
+
+
+def _resolve_band_freqs(
+    band: str,
+    freq_low: Optional[float],
+    freq_high: Optional[float],
+) -> tuple[float, float]:
+    """Resolve band preset or custom range to (freq_low, freq_high)."""
+    if band in BAND_PRESETS:
+        return BAND_PRESETS[band]
+    if band != "custom":
+        raise ValueError(f"Invalid band: {band}. Must be one of: bass, mid, treble, custom")
+    fl = float(freq_low) if freq_low is not None else 20.0
+    fh = float(freq_high) if freq_high is not None else 20000.0
+    if not (20.0 <= fl < fh <= 20000.0):
+        raise ValueError(f"Invalid frequency range: {fl}-{fh} Hz (must be 20-20000, low < high)")
+    return fl, fh

server/src/wled_controller/templates/modals/audio-source-editor.html

@@ -80,6 +80,45 @@
                     </div>
                 </div>
 
+                <!-- Band Extract fields -->
+                <div id="audio-source-band-extract-section" style="display:none">
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="audio-source-band-parent" data-i18n="audio_source.band_parent">Parent Audio Source:</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?" data-i18n-aria-label="aria.hint">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="audio_source.band_parent.hint">Audio source to extract the frequency band from</small>
+                        <select id="audio-source-band-parent">
+                            <!-- populated dynamically with all audio sources -->
+                        </select>
+                    </div>
+
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="audio-source-band" data-i18n="audio_source.band">Frequency Band:</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?" data-i18n-aria-label="aria.hint">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="audio_source.band.hint">Select a frequency band preset or custom range</small>
+                        <select id="audio-source-band" onchange="onBandPresetChange()">
+                            <option value="bass" data-i18n="audio_source.band.bass">Bass (20–250 Hz)</option>
+                            <option value="mid" data-i18n="audio_source.band.mid">Mid (250–4000 Hz)</option>
+                            <option value="treble" data-i18n="audio_source.band.treble">Treble (4000–20000 Hz)</option>
+                            <option value="custom" data-i18n="audio_source.band.custom">Custom Range</option>
+                        </select>
+                    </div>
+
+                    <div id="audio-source-custom-freq" style="display:none">
+                        <div class="form-group">
+                            <label for="audio-source-freq-low" data-i18n="audio_source.freq_low">Low Frequency (Hz):</label>
+                            <input type="number" id="audio-source-freq-low" min="20" max="20000" value="20" step="1">
+                        </div>
+                        <div class="form-group">
+                            <label for="audio-source-freq-high" data-i18n="audio_source.freq_high">High Frequency (Hz):</label>
+                            <input type="number" id="audio-source-freq-high" min="20" max="20000" value="20000" step="1">
+                        </div>
+                    </div>
+                </div>
+
                 <!-- Description -->
                 <div class="form-group">
                     <div class="label-row">