diff --git a/client/public/help.json b/client/public/help.json
index d4735f5..e8d72c9 100644
--- a/client/public/help.json
+++ b/client/public/help.json
@@ -87,7 +87,7 @@
         },
         {
           "keys": "Piano mode",
-          "description": "When using a piano: 1-9 changes instrument, ASDFGHJKL;' plays C major notes, WETYUOP] plays sharps, Enter/Escape exits"
+          "description": "When using a piano: 1-9 (and 0 for the 10th slot) changes instrument, ASDFGHJKL;' plays C major notes, WETYUOP] plays sharps, Enter/Escape exits"
         }
       ]
     },
diff --git a/client/public/version.js b/client/public/version.js
index 21fda7e..a3a5674 100644
--- a/client/public/version.js
+++ b/client/public/version.js
@@ -1,5 +1,5 @@
 // Maintainer-controlled web client version.
 // Format: YYYY.MM.DD Rn (example: 2026.02.20 R2)
-window.CHGRID_WEB_VERSION = "2026.02.22 R202";
+window.CHGRID_WEB_VERSION = "2026.02.22 R203";
 // Optional display timezone for timestamps. Falls back to America/Detroit if unset/invalid.
 window.CHGRID_TIME_ZONE = "America/Detroit";
diff --git a/client/src/audio/pianoSynth.ts b/client/src/audio/pianoSynth.ts
index 43ce39b..d703f70 100644
--- a/client/src/audio/pianoSynth.ts
+++ b/client/src/audio/pianoSynth.ts
@@ -8,6 +8,7 @@ export const PIANO_INSTRUMENT_OPTIONS = [
   'bass',
   'violin',
   'synth_lead',
+  'brass',
   'nintendo',
   'drum_kit',
 ] as const;
@@ -20,6 +21,7 @@ type VoiceRuntime = {
   oscillators: OscillatorNode[];
   modulators: OscillatorNode[];
   releaseSeconds: number;
+  sourceGroupId: string;
 };
 
 type PianoContext = {
@@ -116,10 +118,21 @@ const PRESETS: Record<Exclude<PianoInstrumentId, 'drum_kit'>, InstrumentPreset>
     releaseScale: 1,
     vibrato: { rateHz: 6.8, depthCents: 9 },
   },
+  brass: {
+    oscillators: [
+      { type: 'sawtooth', gain: 0.72 },
+      { type: 'square', ratio: 2, gain: 0.2 },
+    ],
+    filter: { type: 'lowpass', frequency: 3300, q: 1.05 },
+    gain: 0.22,
+    sustainRatio: 0.62,
+    releaseScale: 0.92,
+    vibrato: { rateHz: 5.1, depthCents: 5 },
+  },
   nintendo: {
     oscillators: [
       { type: 'square', gain: 1 },
-      { type: 'square', detune: 8, gain: 0.16 },
+      { type: 'square', detune: 2, gain: 0.08 },
     ],
     filter: { type: 'lowpass', frequency: 5200, q: 1.2 },
     gain: 0.22,
@@ -136,10 +149,11 @@ export const DEFAULT_PIANO_SETTINGS_BY_INSTRUMENT: Record<
   electric_piano: { attack: 12, decay: 40, release: 30, brightness: 62 },
   guitar: { attack: 8, decay: 35, release: 25, brightness: 50 },
   organ: { attack: 25, decay: 70, release: 45, brightness: 48 },
-  bass: { attack: 10, decay: 35, release: 28, brightness: 38 },
+  bass: { attack: 2, decay: 24, release: 18, brightness: 34 },
   violin: { attack: 22, decay: 75, release: 55, brightness: 58 },
   synth_lead: { attack: 6, decay: 30, release: 22, brightness: 72 },
-  nintendo: { attack: 2, decay: 28, release: 18, brightness: 85 },
+  brass: { attack: 10, decay: 45, release: 30, brightness: 60 },
+  nintendo: { attack: 1, decay: 24, release: 15, brightness: 85 },
   drum_kit: { attack: 1, decay: 22, release: 12, brightness: 68 },
 };
 
@@ -167,6 +181,28 @@ function brightnessPercentToMultiplier(value: number): number {
   return 0.45 + (clamped / 100) * 1.55;
 }
 
+/** Maps midi note number to one deterministic drum voice variant. */
+function drumVariantForMidi(midi: number): DrumVariant {
+  const palette: DrumVariant[] = [
+    'kick_sub',
+    'kick_punch',
+    'snare_tight',
+    'snare_body',
+    'hat_closed',
+    'hat_open',
+    'tom_low',
+    'tom_mid',
+    'tom_high',
+    'clap',
+    'pow_mid',
+    'pow_high',
+    'snare_noise',
+    'noise_8bit',
+  ];
+  const index = ((Math.round(midi) % palette.length) + palette.length) % palette.length;
+  return palette[index];
+}
+
 /** Converts midi note number to frequency in hertz. */
 function midiToFrequency(midi: number): number {
   return 440 * Math.pow(2, (midi - 69) / 12);
@@ -181,11 +217,25 @@ function safeStop(oscillator: OscillatorNode, when: number): void {
   }
 }
 
-type DrumVariant = 'kick_808' | 'snare' | 'clap' | 'hat_closed' | 'hat_open' | 'tom_low' | 'tom_high' | 'noise_8bit';
-const DRUM_VARIANTS: DrumVariant[] = ['kick_808', 'snare', 'clap', 'hat_closed', 'hat_open', 'tom_low', 'tom_high', 'noise_8bit'];
+type DrumVariant =
+  | 'kick_sub'
+  | 'kick_punch'
+  | 'snare_tight'
+  | 'snare_body'
+  | 'snare_noise'
+  | 'clap'
+  | 'hat_closed'
+  | 'hat_open'
+  | 'tom_low'
+  | 'tom_mid'
+  | 'tom_high'
+  | 'pow_mid'
+  | 'pow_high'
+  | 'noise_8bit';
 
 export class PianoSynth {
   private readonly voices = new Map<string, VoiceRuntime>();
+  private readonly activeVoiceKeysByGroup = new Map<string, Set<string>>();
   private readonly drumNoiseBuffers = new WeakMap<AudioContext, AudioBuffer>();
   private readonly bitNoiseBuffers = new WeakMap<AudioContext, AudioBuffer>();
 
@@ -199,8 +249,10 @@ export class PianoSynth {
   /** Starts one note for a specific keyboard key id. */
   noteOn(
     keyId: string,
+    sourceGroupId: string,
     midi: number,
     instrument: PianoInstrumentId,
+    voiceMode: 'mono' | 'poly',
     attackPercent: number,
     decayPercent: number,
     releasePercent: number,
@@ -209,8 +261,16 @@ export class PianoSynth {
     spatial: PianoSpatialSource,
   ): void {
     if (this.voices.has(keyId)) return;
+    if (voiceMode === 'mono') {
+      const previousKeys = this.activeVoiceKeysByGroup.get(sourceGroupId);
+      if (previousKeys) {
+        for (const previousKey of Array.from(previousKeys)) {
+          this.noteOff(previousKey);
+        }
+      }
+    }
     if (instrument === 'drum_kit') {
-      this.playDrumHit(keyId, midi, context, spatial, attackPercent, decayPercent, releasePercent, brightnessPercent);
+      this.playDrumHit(midi, context, spatial, attackPercent, decayPercent, releasePercent, brightnessPercent);
       return;
     }
 
@@ -284,7 +344,11 @@ export class PianoSynth {
       oscillators,
       modulators,
       releaseSeconds,
+      sourceGroupId,
     });
+    const groupKeys = this.activeVoiceKeysByGroup.get(sourceGroupId) ?? new Set<string>();
+    groupKeys.add(keyId);
+    this.activeVoiceKeysByGroup.set(sourceGroupId, groupKeys);
   }
 
   /** Releases one active note tied to a keyboard key id. */
@@ -292,6 +356,15 @@ export class PianoSynth {
     const voice = this.voices.get(keyId);
     if (!voice) return;
     this.voices.delete(keyId);
+    const groupKeys = this.activeVoiceKeysByGroup.get(voice.sourceGroupId);
+    if (groupKeys) {
+      groupKeys.delete(keyId);
+      if (groupKeys.size === 0) {
+        this.activeVoiceKeysByGroup.delete(voice.sourceGroupId);
+      } else {
+        this.activeVoiceKeysByGroup.set(voice.sourceGroupId, groupKeys);
+      }
+    }
     const now = voice.gain.context.currentTime;
     const currentGain = Math.max(0.0001, voice.gain.gain.value);
     voice.gain.gain.cancelScheduledValues(now);
@@ -321,7 +394,6 @@ export class PianoSynth {
 
   /** Plays one synthesized drum hit for drum-kit instrument mode. */
   private playDrumHit(
-    keyId: string,
     midi: number,
     context: PianoContext,
     spatial: PianoSpatialSource,
@@ -338,8 +410,8 @@ export class PianoSynth {
       baseGain: 1,
     });
     if (!spatialMix || spatialMix.gain <= 0) return;
-    const typeIndex = Math.abs((midi % DRUM_VARIANTS.length) + this.hashKey(keyId)) % DRUM_VARIANTS.length;
-    const variant = DRUM_VARIANTS[typeIndex];
+    const variant = drumVariantForMidi(midi);
+    const midiOffset = (Math.round(midi) - 60) / 24;
     const decaySeconds = 0.03 + decayPercentToSeconds(decayPercent) * 0.5;
     const releaseSeconds = 0.02 + releasePercentToSeconds(releasePercent) * 0.35;
     const attackSeconds = Math.max(0.001, attackPercentToSeconds(attackPercent) * 0.18);
@@ -350,26 +422,45 @@ export class PianoSynth {
     gain.gain.exponentialRampToValueAtTime(0.22 * spatialMix.gain, now + attackSeconds);
     gain.gain.exponentialRampToValueAtTime(0.0001, now + decaySeconds);
 
-    let tailNode: AudioNode = gain;
     if (typeof context.audioCtx.createStereoPanner === 'function') {
       const panner = context.audioCtx.createStereoPanner();
       panner.pan.setValueAtTime(spatialMix.pan, now);
-      tailNode.connect(panner).connect(context.destination);
-      tailNode = panner;
+      gain.connect(panner).connect(context.destination);
     } else {
-      tailNode.connect(context.destination);
+      gain.connect(context.destination);
     }
 
-    if (variant === 'kick_808') {
-      this.playKick808(context, gain, now, decaySeconds + releaseSeconds * 0.35);
+    if (variant === 'kick_sub') {
+      this.playKick808(context, gain, now, (decaySeconds + releaseSeconds * 0.35) * 1.15, 145, 36);
+      return;
+    }
+    if (variant === 'kick_punch') {
+      this.playKick808(context, gain, now, decaySeconds + releaseSeconds * 0.2, 185, 52);
+      return;
+    }
+    if (variant === 'snare_tight') {
+      this.playSnare(context, gain, now, decaySeconds * 0.55 + releaseSeconds * 0.08, 0.75);
+      return;
+    }
+    if (variant === 'snare_body') {
+      this.playSnare(context, gain, now, decaySeconds * 0.92 + releaseSeconds * 0.18, 1);
+      return;
+    }
+    if (variant === 'snare_noise') {
+      this.playSnare(context, gain, now, decaySeconds * 0.8 + releaseSeconds * 0.15, 0.45);
+      this.playNoiseDrum(context, gain, now, decaySeconds * 0.75, 'highpass', 1900 * brightnessMultiplier, true);
       return;
     }
     if (variant === 'tom_low') {
-      this.playTom(context, gain, now, 120, 68, decaySeconds * 0.95 + releaseSeconds * 0.2);
+      this.playTom(context, gain, now, 120, 70, decaySeconds * 0.95 + releaseSeconds * 0.2);
+      return;
+    }
+    if (variant === 'tom_mid') {
+      this.playTom(context, gain, now, 175, 100, decaySeconds * 0.86 + releaseSeconds * 0.16);
       return;
     }
     if (variant === 'tom_high') {
-      this.playTom(context, gain, now, 220, 125, decaySeconds * 0.8 + releaseSeconds * 0.16);
+      this.playTom(context, gain, now, 250, 138, decaySeconds * 0.78 + releaseSeconds * 0.14);
       return;
     }
     if (variant === 'hat_closed') {
@@ -380,23 +471,38 @@ export class PianoSynth {
       this.playNoiseDrum(context, gain, now, decaySeconds * 0.8 + releaseSeconds * 0.2, 'highpass', 5200 * brightnessMultiplier, false);
       return;
     }
-    if (variant === 'noise_8bit') {
-      this.playNoiseDrum(context, gain, now, decaySeconds * 0.45, 'bandpass', 2700 * brightnessMultiplier, true);
-      return;
-    }
     if (variant === 'clap') {
       this.playClap(context, gain, now, decaySeconds + releaseSeconds * 0.1);
       return;
     }
-    this.playSnare(context, gain, now, decaySeconds + releaseSeconds * 0.12);
+    if (variant === 'pow_mid') {
+      this.playPowDown(context, gain, now, 310 + midiOffset * 30, 150 + midiOffset * 15, decaySeconds * 0.95 + releaseSeconds * 0.15);
+      return;
+    }
+    if (variant === 'pow_high') {
+      this.playPowDown(context, gain, now, 420 + midiOffset * 40, 210 + midiOffset * 22, decaySeconds * 0.88 + releaseSeconds * 0.12);
+      return;
+    }
+    if (variant === 'noise_8bit') {
+      this.playNoiseDrum(context, gain, now, decaySeconds * 0.45, 'bandpass', 2700 * brightnessMultiplier, true);
+      return;
+    }
+    this.playSnare(context, gain, now, decaySeconds + releaseSeconds * 0.12, 1);
   }
 
   /** 808-like kick: deep sine sweep with long-ish tail. */
-  private playKick808(context: PianoContext, gain: GainNode, now: number, decaySeconds: number): void {
+  private playKick808(
+    context: PianoContext,
+    gain: GainNode,
+    now: number,
+    decaySeconds: number,
+    startHz: number,
+    endHz: number,
+  ): void {
     const kick = context.audioCtx.createOscillator();
     kick.type = 'sine';
-    kick.frequency.setValueAtTime(160, now);
-    kick.frequency.exponentialRampToValueAtTime(42, now + Math.max(0.07, decaySeconds * 0.95));
+    kick.frequency.setValueAtTime(startHz, now);
+    kick.frequency.exponentialRampToValueAtTime(endHz, now + Math.max(0.07, decaySeconds * 0.95));
     const body = context.audioCtx.createGain();
     body.gain.setValueAtTime(1, now);
     body.gain.exponentialRampToValueAtTime(0.0001, now + Math.max(0.08, decaySeconds));
@@ -440,13 +546,13 @@ export class PianoSynth {
   }
 
   /** Snare: short tone + filtered noise burst. */
-  private playSnare(context: PianoContext, gain: GainNode, now: number, decaySeconds: number): void {
+  private playSnare(context: PianoContext, gain: GainNode, now: number, decaySeconds: number, toneLevel: number): void {
     const tone = context.audioCtx.createOscillator();
     tone.type = 'triangle';
     tone.frequency.setValueAtTime(220, now);
     tone.frequency.exponentialRampToValueAtTime(130, now + Math.max(0.03, decaySeconds * 0.45));
     const toneGain = context.audioCtx.createGain();
-    toneGain.gain.setValueAtTime(0.45, now);
+    toneGain.gain.setValueAtTime(0.45 * Math.max(0, toneLevel), now);
     toneGain.gain.exponentialRampToValueAtTime(0.0001, now + Math.max(0.04, decaySeconds * 0.55));
     tone.connect(toneGain).connect(gain);
     tone.start(now);
@@ -473,13 +579,22 @@ export class PianoSynth {
     }
   }
 
-  /** Returns deterministic hash for key ids to map drum voice variants. */
-  private hashKey(value: string): number {
-    let out = 0;
-    for (let index = 0; index < value.length; index += 1) {
-      out = ((out << 5) - out + value.charCodeAt(index)) | 0;
-    }
-    return out;
+  /** Retro game-like downward-bending midrange hit for drum fills. */
+  private playPowDown(context: PianoContext, gain: GainNode, now: number, startHz: number, endHz: number, decaySeconds: number): void {
+    const osc = context.audioCtx.createOscillator();
+    osc.type = 'square';
+    osc.frequency.setValueAtTime(startHz, now);
+    osc.frequency.exponentialRampToValueAtTime(Math.max(35, endHz), now + Math.max(0.04, decaySeconds * 0.9));
+    const amp = context.audioCtx.createGain();
+    amp.gain.setValueAtTime(0.75, now);
+    amp.gain.exponentialRampToValueAtTime(0.0001, now + Math.max(0.06, decaySeconds));
+    const filter = context.audioCtx.createBiquadFilter();
+    filter.type = 'bandpass';
+    filter.frequency.setValueAtTime(1700, now);
+    filter.Q.setValueAtTime(1.2, now);
+    osc.connect(filter).connect(amp).connect(gain);
+    osc.start(now);
+    safeStop(osc, now + Math.max(0.08, decaySeconds) + 0.03);
   }
 
   /** Returns or lazily builds short white-noise buffer for percussion synthesis. */
diff --git a/client/src/items/itemPropertyEditor.ts b/client/src/items/itemPropertyEditor.ts
index a32e3f9..cf060aa 100644
--- a/client/src/items/itemPropertyEditor.ts
+++ b/client/src/items/itemPropertyEditor.ts
@@ -317,6 +317,7 @@ export function createItemPropertyEditor(deps: EditorDeps): {
         propertyKey === 'mediaVolume' ||
         propertyKey === 'emitVolume' ||
         propertyKey === 'emitRange' ||
+        propertyKey === 'octave' ||
         propertyKey === 'attack' ||
         propertyKey === 'decay' ||
         propertyKey === 'release' ||
diff --git a/client/src/items/itemRegistry.ts b/client/src/items/itemRegistry.ts
index c917226..8a96183 100644
--- a/client/src/items/itemRegistry.ts
+++ b/client/src/items/itemRegistry.ts
@@ -54,14 +54,16 @@ const DEFAULT_PIANO_INSTRUMENT_OPTIONS = [
   'bass',
   'violin',
   'synth_lead',
+  'brass',
   'nintendo',
   'drum_kit',
 ] as const;
+const DEFAULT_PIANO_VOICE_MODE_OPTIONS = ['poly', 'mono'] as const;
 
 const DEFAULT_ITEM_TYPE_EDITABLE_PROPERTIES: Record<ItemType, string[]> = {
   radio_station: ['title', 'streamUrl', 'enabled', 'mediaVolume', 'mediaChannel', 'mediaEffect', 'mediaEffectValue', 'facing', 'emitRange'],
   dice: ['title', 'sides', 'number'],
-  piano: ['title', 'instrument', 'attack', 'decay', 'release', 'brightness', 'emitRange'],
+  piano: ['title', 'instrument', 'voiceMode', 'octave', 'attack', 'decay', 'release', 'brightness', 'emitRange'],
   wheel: ['title', 'spaces'],
   clock: ['title', 'timeZone', 'use24Hour'],
   widget: ['title', 'enabled', 'directional', 'facing', 'emitRange', 'emitVolume', 'emitSoundSpeed', 'emitSoundTempo', 'emitEffect', 'emitEffectValue', 'useSound', 'emitSound'],
@@ -133,6 +135,7 @@ let optionItemPropertyValues: Partial<Record<string, string[]>> = {
   emitEffect: EFFECT_SEQUENCE.map((effect) => effect.id),
   mediaChannel: [...RADIO_CHANNEL_OPTIONS],
   instrument: [...DEFAULT_PIANO_INSTRUMENT_OPTIONS],
+  voiceMode: [...DEFAULT_PIANO_VOICE_MODE_OPTIONS],
   timeZone: [...DEFAULT_CLOCK_TIME_ZONE_OPTIONS],
 };
 let itemTypePropertyMetadata: Partial<Record<ItemType, Record<string, ItemPropertyMetadata>>> = {};
@@ -239,6 +242,8 @@ export function itemPropertyLabel(key: string): string {
   if (key === 'emitEffect') return 'emit effect';
   if (key === 'emitEffectValue') return 'emit effect value';
   if (key === 'instrument') return 'instrument';
+  if (key === 'voiceMode') return 'voice mode';
+  if (key === 'octave') return 'octave';
   if (key === 'attack') return 'attack';
   if (key === 'decay') return 'decay';
   if (key === 'release') return 'release';
diff --git a/client/src/main.ts b/client/src/main.ts
index 3459499..3d6f94c 100644
--- a/client/src/main.ts
+++ b/client/src/main.ts
@@ -255,6 +255,7 @@ let activeTeleportLoopStop: (() => void) | null = null;
 let activeTeleportLoopToken = 0;
 let activePianoItemId: string | null = null;
 const activePianoKeys = new Set<string>();
+const activePianoKeyMidi = new Map<string, number>();
 const activeRemotePianoKeys = new Set<string>();
 let pianoPreviewTimeoutId: number | null = null;
 let activeTeleport:
@@ -796,6 +797,8 @@ function getItemSpatialConfig(item: WorldItem): { range: number; directional: bo
 /** Resolves piano params with safe defaults for local play mode. */
 function getPianoParams(item: WorldItem): {
   instrument: PianoInstrumentId;
+  voiceMode: 'mono' | 'poly';
+  octave: number;
   attack: number;
   decay: number;
   release: number;
@@ -816,12 +819,16 @@ function getPianoParams(item: WorldItem): {
       : 'piano';
   const rawAttack = Number(item.params.attack);
   const rawDecay = Number(item.params.decay);
+  const rawOctave = Number(item.params.octave);
+  const rawVoiceMode = String(item.params.voiceMode ?? defaultsVoiceModeForInstrument(instrument)).trim().toLowerCase();
   const rawRelease = Number(item.params.release);
   const rawBrightness = Number(item.params.brightness);
   const rawEmitRange = Number(item.params.emitRange ?? getItemTypeGlobalProperties(item.type).emitRange ?? 15);
   const defaults = DEFAULT_PIANO_SETTINGS_BY_INSTRUMENT[instrument];
   return {
     instrument,
+    voiceMode: rawVoiceMode === 'mono' ? 'mono' : 'poly',
+    octave: Math.max(-2, Math.min(2, Number.isFinite(rawOctave) ? Math.round(rawOctave) : defaultsOctaveForInstrument(instrument))),
     attack: Math.max(0, Math.min(100, Number.isFinite(rawAttack) ? Math.round(rawAttack) : defaults.attack)),
     decay: Math.max(0, Math.min(100, Number.isFinite(rawDecay) ? Math.round(rawDecay) : defaults.decay)),
     release: Math.max(0, Math.min(100, Number.isFinite(rawRelease) ? Math.round(rawRelease) : defaults.release)),
@@ -830,6 +837,17 @@ function getPianoParams(item: WorldItem): {
   };
 }
 
+/** Returns default voice mode for a given piano instrument. */
+function defaultsVoiceModeForInstrument(instrument: PianoInstrumentId): 'mono' | 'poly' {
+  if (instrument === 'bass' || instrument === 'violin' || instrument === 'brass') return 'mono';
+  return 'poly';
+}
+
+/** Returns default octave offset for a given piano instrument. */
+function defaultsOctaveForInstrument(instrument: PianoInstrumentId): number {
+  return instrument === 'bass' ? -1 : 0;
+}
+
 /** Normalizes arbitrary instrument strings into supported piano synth ids. */
 function normalizePianoInstrument(value: unknown): PianoInstrumentId {
   const raw = String(value ?? 'piano').trim().toLowerCase();
@@ -839,6 +857,7 @@ function normalizePianoInstrument(value: unknown): PianoInstrumentId {
   if (raw === 'bass') return 'bass';
   if (raw === 'violin') return 'violin';
   if (raw === 'synth_lead') return 'synth_lead';
+  if (raw === 'brass') return 'brass';
   if (raw === 'nintendo') return 'nintendo';
   if (raw === 'drum_kit') return 'drum_kit';
   return 'piano';
@@ -872,13 +891,14 @@ function stopPianoUseMode(announce = true): void {
   if (!activePianoItemId) return;
   const itemId = activePianoItemId;
   for (const code of Array.from(activePianoKeys)) {
-    const midi = getPianoMidiForCode(code);
-    if (midi === null) continue;
+    const midi = activePianoKeyMidi.get(code);
+    if (!Number.isFinite(midi)) continue;
     signaling.send({ type: 'item_piano_note', itemId, keyId: code, midi, on: false });
     pianoSynth.noteOff(code);
   }
   activePianoItemId = null;
   activePianoKeys.clear();
+  activePianoKeyMidi.clear();
   state.mode = 'normal';
   if (announce) {
     updateStatus('Stopped piano.');
@@ -908,8 +928,10 @@ async function previewPianoSettingChange(
   pianoSynth.noteOff(previewKeyId);
   pianoSynth.noteOn(
     previewKeyId,
+    'preview',
     60,
     instrument,
+    'poly',
     attack,
     decay,
     release,
@@ -933,6 +955,8 @@ function playRemotePianoNote(note: {
   keyId: string;
   midi: number;
   instrument: string;
+  voiceMode: 'mono' | 'poly';
+  octave: number;
   attack: number;
   decay: number;
   release: number;
@@ -944,13 +968,18 @@ function playRemotePianoNote(note: {
   const ctx = audio.context;
   const destination = audio.getOutputDestinationNode();
   if (!ctx || !destination) return;
-  const runtimeKey = `${note.senderId}:${note.keyId}`;
+  const runtimeKey = `${note.senderId}:${note.itemId}:${note.keyId}`;
   if (activeRemotePianoKeys.has(runtimeKey)) return;
+  if (note.voiceMode === 'mono') {
+    stopRemotePianoNotesForSource(note.senderId, note.itemId);
+  }
   activeRemotePianoKeys.add(runtimeKey);
   pianoSynth.noteOn(
     runtimeKey,
+    `remote:${note.senderId}:${note.itemId}`,
     Math.max(0, Math.min(127, Math.round(note.midi))),
     normalizePianoInstrument(note.instrument),
+    note.voiceMode,
     Math.max(0, Math.min(100, Math.round(note.attack))),
     Math.max(0, Math.min(100, Math.round(note.decay))),
     Math.max(0, Math.min(100, Math.round(note.release))),
@@ -966,9 +995,13 @@ function playRemotePianoNote(note: {
 
 /** Stops one inbound piano note previously started for another user. */
 function stopRemotePianoNote(senderId: string, keyId: string): void {
-  const runtimeKey = `${senderId}:${keyId}`;
-  if (!activeRemotePianoKeys.delete(runtimeKey)) return;
-  pianoSynth.noteOff(runtimeKey);
+  const suffix = `:${keyId}`;
+  for (const runtimeKey of Array.from(activeRemotePianoKeys)) {
+    if (!runtimeKey.startsWith(`${senderId}:`)) continue;
+    if (!runtimeKey.endsWith(suffix)) continue;
+    activeRemotePianoKeys.delete(runtimeKey);
+    pianoSynth.noteOff(runtimeKey);
+  }
 }
 
 /** Stops all currently active remote piano notes for a sender id. */
@@ -981,6 +1014,16 @@ function stopAllRemotePianoNotesForSender(senderId: string): void {
   }
 }
 
+/** Stops all remote piano notes for one sender+item source group. */
+function stopRemotePianoNotesForSource(senderId: string, itemId: string): void {
+  const prefix = `${senderId}:${itemId}:`;
+  for (const runtimeKey of Array.from(activeRemotePianoKeys)) {
+    if (!runtimeKey.startsWith(prefix)) continue;
+    activeRemotePianoKeys.delete(runtimeKey);
+    pianoSynth.noteOff(runtimeKey);
+  }
+}
+
 /** Enters help-view mode and announces the first help line. */
 function openHelpViewer(): void {
   if (helpViewerLines.length === 0) {
@@ -1195,7 +1238,7 @@ function getItemPropertyValue(item: WorldItem, key: string): string {
 function inferItemPropertyValueType(item: WorldItem, key: string): string | undefined {
   if (key === 'useSound' || key === 'emitSound') return 'sound';
   if (key === 'enabled' || key === 'use24Hour' || key === 'directional') return 'boolean';
-  if (key === 'mediaChannel' || key === 'mediaEffect' || key === 'emitEffect' || key === 'timeZone' || key === 'instrument') return 'list';
+  if (key === 'mediaChannel' || key === 'mediaEffect' || key === 'emitEffect' || key === 'timeZone' || key === 'instrument' || key === 'voiceMode') return 'list';
   if (
     key === 'x' ||
     key === 'y' ||
@@ -1208,6 +1251,7 @@ function inferItemPropertyValueType(item: WorldItem, key: string): string | unde
     key === 'emitEffectValue' ||
     key === 'facing' ||
     key === 'emitRange' ||
+    key === 'octave' ||
     key === 'attack' ||
     key === 'decay' ||
     key === 'release' ||
@@ -2285,11 +2329,16 @@ function handlePianoUseModeInput(code: string): void {
   }
   if (code.startsWith('Digit')) {
     const digit = Number(code.slice(5));
-    if (Number.isInteger(digit) && digit >= 1 && digit <= 9) {
-      const instrument = PIANO_INSTRUMENT_OPTIONS[digit - 1];
+    const instrumentIndex = digit === 0 ? 9 : digit - 1;
+    if (Number.isInteger(instrumentIndex) && instrumentIndex >= 0 && instrumentIndex < PIANO_INSTRUMENT_OPTIONS.length) {
+      const instrument = PIANO_INSTRUMENT_OPTIONS[instrumentIndex];
       if (instrument) {
         const defaults = DEFAULT_PIANO_SETTINGS_BY_INSTRUMENT[instrument];
+        const voiceMode = defaultsVoiceModeForInstrument(instrument);
+        const octave = defaultsOctaveForInstrument(instrument);
         item.params.instrument = instrument;
+        item.params.voiceMode = voiceMode;
+        item.params.octave = octave;
         item.params.attack = defaults.attack;
         item.params.decay = defaults.decay;
         item.params.release = defaults.release;
@@ -2317,17 +2366,21 @@ function handlePianoUseModeInput(code: string): void {
   const midi = getPianoMidiForCode(code);
   if (midi === null) return;
   if (activePianoKeys.has(code)) return;
+  const config = getPianoParams(item);
+  const playedMidi = Math.max(0, Math.min(127, midi + config.octave * 12));
   activePianoKeys.add(code);
+  activePianoKeyMidi.set(code, playedMidi);
   const ctx = audio.context;
   const destination = audio.getOutputDestinationNode();
   if (!ctx || !destination) return;
-  const config = getPianoParams(item);
   const sourceX = item.carrierId === state.player.id ? state.player.x : item.x;
   const sourceY = item.carrierId === state.player.id ? state.player.y : item.y;
   pianoSynth.noteOn(
     code,
-    midi,
+    `local:${itemId}`,
+    playedMidi,
     config.instrument,
+    config.voiceMode,
     config.attack,
     config.decay,
     config.release,
@@ -2335,7 +2388,7 @@ function handlePianoUseModeInput(code: string): void {
     { audioCtx: ctx, destination },
     { x: sourceX - state.player.x, y: sourceY - state.player.y, range: config.emitRange },
   );
-  signaling.send({ type: 'item_piano_note', itemId, keyId: code, midi, on: true });
+  signaling.send({ type: 'item_piano_note', itemId, keyId: code, midi: playedMidi, on: true });
 }
 
 /** Handles effect menu list navigation and selection. */
@@ -2623,6 +2676,10 @@ const itemPropertyEditor = createItemPropertyEditor({
       const brightness = Number(value);
       if (!Number.isFinite(brightness)) return;
       void previewPianoSettingChange(item, { brightness });
+      return;
+    }
+    if (key === 'octave') {
+      void previewPianoSettingChange(item, {});
     }
   },
   updateStatus,
@@ -2802,8 +2859,9 @@ function setupInputHandlers(): void {
       if (activePianoKeys.delete(code)) {
         pianoSynth.noteOff(code);
         const itemId = activePianoItemId;
-        const midi = getPianoMidiForCode(code);
-        if (itemId && midi !== null) {
+        const midi = activePianoKeyMidi.get(code);
+        activePianoKeyMidi.delete(code);
+        if (itemId && Number.isFinite(midi)) {
           signaling.send({ type: 'item_piano_note', itemId, keyId: code, midi, on: false });
         }
       }
diff --git a/client/src/network/messageHandlers.ts b/client/src/network/messageHandlers.ts
index b064dfd..c23307c 100644
--- a/client/src/network/messageHandlers.ts
+++ b/client/src/network/messageHandlers.ts
@@ -52,6 +52,8 @@ type MessageHandlerDeps = {
     keyId: string;
     midi: number;
     instrument: string;
+    voiceMode: 'mono' | 'poly';
+    octave: number;
     attack: number;
     decay: number;
     release: number;
@@ -275,6 +277,8 @@ export function createOnMessageHandler(deps: MessageHandlerDeps): (message: Inco
             keyId: message.keyId,
             midi: message.midi,
             instrument: message.instrument,
+            voiceMode: message.voiceMode,
+            octave: message.octave,
             attack: message.attack,
             decay: message.decay,
             release: message.release,
diff --git a/client/src/network/protocol.ts b/client/src/network/protocol.ts
index aab9a4a..a78303f 100644
--- a/client/src/network/protocol.ts
+++ b/client/src/network/protocol.ts
@@ -158,6 +158,8 @@ export const itemPianoNoteSchema = z.object({
   midi: z.number().int().min(0).max(127),
   on: z.boolean(),
   instrument: z.string(),
+  voiceMode: z.enum(['mono', 'poly']),
+  octave: z.number().int().min(-2).max(2),
   attack: z.number().int().min(0).max(100),
   decay: z.number().int().min(0).max(100),
   release: z.number().int().min(0).max(100),
diff --git a/docs/controls.md b/docs/controls.md
index 7311f2c..4f9c948 100644
--- a/docs/controls.md
+++ b/docs/controls.md
@@ -76,7 +76,7 @@ Applies to effect select, user/item list modes, item selection, item property li
 
 ## Piano Use Mode
 
-- `1-9`: Switch instrument preset quickly
+- `1-9` (and `0` for the 10th slot): Switch instrument preset quickly
 - `A S D F G H J K L ; '`: Play white keys (C major from C4 upward)
 - `W E T Y U O P ]`: Play sharps
 - Multiple keys can be held/played at once
diff --git a/docs/item-schema.md b/docs/item-schema.md
index 0be6c33..babddf9 100644
--- a/docs/item-schema.md
+++ b/docs/item-schema.md
@@ -163,6 +163,8 @@
 ```json
 {
   "instrument": "piano",
+  "voiceMode": "poly",
+  "octave": 0,
   "attack": 15,
   "decay": 45,
   "release": 35,
@@ -172,8 +174,10 @@
 ```
 
 - `instrument`: one of
-  `piano | electric_piano | guitar | organ | bass | violin | synth_lead | nintendo | drum_kit`.
-- Selecting a new instrument resets `attack`/`decay` to that instrument's defaults.
+  `piano | electric_piano | guitar | organ | bass | violin | synth_lead | brass | nintendo | drum_kit`.
+- `voiceMode`: one of `poly | mono`.
+- `octave`: integer, range `-2..2` (default `0`; bass defaults to `-1`).
+- Selecting a new instrument resets `voiceMode`/`octave`/`attack`/`decay`/`release`/`brightness` to that instrument's defaults.
 - `attack`: integer, range `0-100`, default `15`.
 - `decay`: integer, range `0-100`, default `45`.
 - `release`: integer, range `0-100`, default `35`.
@@ -235,8 +239,12 @@
   "midi": 60,
   "on": true,
   "instrument": "piano",
+  "voiceMode": "poly",
+  "octave": 0,
   "attack": 15,
   "decay": 45,
+  "release": 35,
+  "brightness": 55,
   "x": 12,
   "y": 8,
   "emitRange": 15
diff --git a/docs/item-types.md b/docs/item-types.md
index a357e11..bc72030 100644
--- a/docs/item-types.md
+++ b/docs/item-types.md
@@ -157,6 +157,8 @@ This is behavior-focused documentation for item types and their defaults.
 - Title: `piano`
 - Params:
   - `instrument="piano"`
+  - `voiceMode="poly"`
+  - `octave=0`
   - `attack=15`
   - `decay=45`
   - `release=35`
@@ -173,13 +175,15 @@ This is behavior-focused documentation for item types and their defaults.
 - Announces that the user begins playing the piano (client enters piano key mode).
 
 ### Validation
-- `instrument`: `piano | electric_piano | guitar | organ | bass | violin | synth_lead | nintendo | drum_kit`
+- `instrument`: `piano | electric_piano | guitar | organ | bass | violin | synth_lead | brass | nintendo | drum_kit`
+- `voiceMode`: `poly | mono`
+- `octave`: integer `-2..2`
 - `attack`: integer `0..100`
 - `decay`: integer `0..100`
 - `release`: integer `0..100`
 - `brightness`: integer `0..100`
 - `emitRange`: integer `5..20`
-- Instrument changes reset `attack`/`decay`/`release`/`brightness` to instrument defaults.
+- Instrument changes reset `voiceMode`/`octave`/`attack`/`decay`/`release`/`brightness` to instrument defaults.
 
 ## Adding A New Item Type (Registry V1)
 
diff --git a/docs/protocol-notes.md b/docs/protocol-notes.md
index ba32bea..39e01aa 100644
--- a/docs/protocol-notes.md
+++ b/docs/protocol-notes.md
@@ -38,7 +38,7 @@ This is a behavior guide for packet semantics beyond raw schemas.
 - `item_use_sound` contains absolute item world coordinates (`x`, `y`) and sound path.
 - `item_piano_note` contains:
   - `itemId`, `senderId`, `keyId`, `midi`, `on`
-  - resolved `instrument`, `attack`, `decay`, `emitRange`
+  - resolved `instrument`, `voiceMode`, `octave`, `attack`, `decay`, `release`, `brightness`, `emitRange`
   - absolute source coordinates `x`, `y`
 
 ## Welcome Metadata
diff --git a/server/app/item_catalog.py b/server/app/item_catalog.py
index 68e4a7d..bb3213f 100644
--- a/server/app/item_catalog.py
+++ b/server/app/item_catalog.py
@@ -20,6 +20,7 @@ CLOCK_TIME_ZONE_OPTIONS = clock.TIME_ZONE_OPTIONS
 RADIO_EFFECT_OPTIONS = radio.EFFECT_OPTIONS
 RADIO_CHANNEL_OPTIONS = radio.CHANNEL_OPTIONS
 PIANO_INSTRUMENT_OPTIONS = piano.INSTRUMENT_OPTIONS
+PIANO_VOICE_MODE_OPTIONS = piano.VOICE_MODE_OPTIONS
 
 
 @dataclass(frozen=True)
@@ -81,6 +82,7 @@ ITEM_PROPERTY_OPTIONS: dict[str, tuple[str, ...]] = {
     "mediaChannel": RADIO_CHANNEL_OPTIONS,
     "timeZone": CLOCK_TIME_ZONE_OPTIONS,
     "instrument": PIANO_INSTRUMENT_OPTIONS,
+    "voiceMode": PIANO_VOICE_MODE_OPTIONS,
 }
 
 ITEM_TYPE_TOOLTIPS: dict[ItemType, str] = {
diff --git a/server/app/items/piano.py b/server/app/items/piano.py
index 33204a0..30d38cd 100644
--- a/server/app/items/piano.py
+++ b/server/app/items/piano.py
@@ -9,7 +9,17 @@ from ..models import WorldItem
 
 LABEL = "piano"
 TOOLTIP = "Playable keyboard instrument with multiple synth voices."
-EDITABLE_PROPERTIES: tuple[str, ...] = ("title", "instrument", "attack", "decay", "release", "brightness", "emitRange")
+EDITABLE_PROPERTIES: tuple[str, ...] = (
+    "title",
+    "instrument",
+    "voiceMode",
+    "octave",
+    "attack",
+    "decay",
+    "release",
+    "brightness",
+    "emitRange",
+)
 CAPABILITIES: tuple[str, ...] = ("editable", "carryable", "deletable", "usable")
 USE_SOUND: str | None = None
 EMIT_SOUND: str | None = None
@@ -19,6 +29,8 @@ DIRECTIONAL = False
 DEFAULT_TITLE = "piano"
 DEFAULT_PARAMS: dict = {
     "instrument": "piano",
+    "voiceMode": "poly",
+    "octave": 0,
     "attack": 15,
     "decay": 45,
     "release": 35,
@@ -34,25 +46,34 @@ INSTRUMENT_OPTIONS: tuple[str, ...] = (
     "bass",
     "violin",
     "synth_lead",
+    "brass",
     "nintendo",
     "drum_kit",
 )
+VOICE_MODE_OPTIONS: tuple[str, ...] = ("poly", "mono")
 
-DEFAULT_ENVELOPE_BY_INSTRUMENT: dict[str, tuple[int, int, int, int]] = {
-    "piano": (15, 45, 35, 55),
-    "electric_piano": (12, 40, 30, 62),
-    "guitar": (8, 35, 25, 50),
-    "organ": (25, 70, 45, 48),
-    "bass": (10, 35, 28, 38),
-    "violin": (22, 75, 55, 58),
-    "synth_lead": (6, 30, 22, 72),
-    "nintendo": (2, 28, 18, 85),
-    "drum_kit": (1, 22, 12, 68),
+DEFAULT_ENVELOPE_BY_INSTRUMENT: dict[str, tuple[int, int, int, int, str, int]] = {
+    "piano": (15, 45, 35, 55, "poly", 0),
+    "electric_piano": (12, 40, 30, 62, "poly", 0),
+    "guitar": (8, 35, 25, 50, "poly", 0),
+    "organ": (25, 70, 45, 48, "poly", 0),
+    "bass": (2, 24, 18, 34, "mono", -1),
+    "violin": (22, 75, 55, 58, "mono", 0),
+    "synth_lead": (6, 30, 22, 72, "poly", 0),
+    "brass": (10, 45, 30, 60, "mono", 0),
+    "nintendo": (1, 24, 15, 85, "poly", 0),
+    "drum_kit": (1, 22, 12, 68, "poly", 0),
 }
 
 PROPERTY_METADATA: dict[str, dict[str, object]] = {
     "title": {"valueType": "text", "tooltip": "Display name spoken and shown for this item.", "maxLength": 80},
     "instrument": {"valueType": "list", "tooltip": "Instrument voice used when playing this piano."},
+    "voiceMode": {"valueType": "list", "tooltip": "Mono plays one note at a time; poly allows chords."},
+    "octave": {
+        "valueType": "number",
+        "tooltip": "Shifts played notes in octaves. -1 is one octave down.",
+        "range": {"min": -2, "max": 2, "step": 1},
+    },
     "attack": {
         "valueType": "number",
         "tooltip": "How quickly notes ramp in. Lower is sharper; higher is softer.",
@@ -90,6 +111,19 @@ def validate_update(_item: WorldItem, next_params: dict) -> dict:
     previous_instrument = str(_item.params.get("instrument", "piano")).strip().lower()
     next_params["instrument"] = instrument
 
+    voice_mode = str(next_params.get("voiceMode", _item.params.get("voiceMode", "poly"))).strip().lower()
+    if voice_mode not in VOICE_MODE_OPTIONS:
+        raise ValueError("voiceMode must be one of: poly, mono.")
+    next_params["voiceMode"] = voice_mode
+
+    try:
+        octave = int(next_params.get("octave", _item.params.get("octave", 0)))
+    except (TypeError, ValueError) as exc:
+        raise ValueError("octave must be an integer between -2 and 2.") from exc
+    if not (-2 <= octave <= 2):
+        raise ValueError("octave must be between -2 and 2.")
+    next_params["octave"] = octave
+
     try:
         attack = int(next_params.get("attack", 15))
     except (TypeError, ValueError) as exc:
@@ -119,7 +153,11 @@ def validate_update(_item: WorldItem, next_params: dict) -> dict:
 
     # When instrument changes, reset envelope to instrument-appropriate defaults.
     if instrument != previous_instrument:
-        attack, decay, release, brightness = DEFAULT_ENVELOPE_BY_INSTRUMENT.get(instrument, (15, 45, 35, 55))
+        attack, decay, release, brightness, voice_mode, octave = DEFAULT_ENVELOPE_BY_INSTRUMENT.get(
+            instrument, (15, 45, 35, 55, "poly", 0)
+        )
+        next_params["voiceMode"] = voice_mode
+        next_params["octave"] = octave
     next_params["attack"] = attack
     next_params["decay"] = decay
     next_params["release"] = release
diff --git a/server/app/models.py b/server/app/models.py
index 5c95940..ac8c55d 100644
--- a/server/app/models.py
+++ b/server/app/models.py
@@ -230,6 +230,8 @@ class ItemPianoNoteBroadcastPacket(BasePacket):
     midi: int
     on: bool
     instrument: str
+    voiceMode: str
+    octave: int
     attack: int
     decay: int
     release: int
diff --git a/server/app/server.py b/server/app/server.py
index b26efe7..b7eb4d4 100644
--- a/server/app/server.py
+++ b/server/app/server.py
@@ -677,6 +677,10 @@ class SignalingServer:
             else:
                 active_keys.discard(packet.keyId)
             instrument = str(item.params.get("instrument", "piano")).strip().lower()
+            voice_mode = str(item.params.get("voiceMode", "poly")).strip().lower()
+            if voice_mode not in {"poly", "mono"}:
+                voice_mode = "poly"
+            octave = int(item.params.get("octave", 0)) if isinstance(item.params.get("octave", 0), (int, float)) else 0
             attack = int(item.params.get("attack", 15)) if isinstance(item.params.get("attack", 15), (int, float)) else 15
             decay = int(item.params.get("decay", 45)) if isinstance(item.params.get("decay", 45), (int, float)) else 45
             release = int(item.params.get("release", 35)) if isinstance(item.params.get("release", 35), (int, float)) else 35
@@ -693,6 +697,8 @@ class SignalingServer:
                     midi=packet.midi,
                     on=packet.on,
                     instrument=instrument,
+                    voiceMode=voice_mode,
+                    octave=max(-2, min(2, octave)),
                     attack=max(0, min(100, attack)),
                     decay=max(0, min(100, decay)),
                     release=max(0, min(100, release)),
diff --git a/server/tests/test_item_use_cooldown.py b/server/tests/test_item_use_cooldown.py
index 71a020f..7b3cb9d 100644
--- a/server/tests/test_item_use_cooldown.py
+++ b/server/tests/test_item_use_cooldown.py
@@ -377,6 +377,8 @@ async def test_piano_update_and_use(monkeypatch: pytest.MonkeyPatch) -> None:
     )
     assert send_payloads[-1].ok is True
     assert item.params.get("instrument") == "drum_kit"
+    assert item.params.get("voiceMode") == "poly"
+    assert item.params.get("octave") == 0
     assert item.params.get("attack") == 1
     assert item.params.get("decay") == 22
     assert item.params.get("release") == 12
@@ -389,9 +391,11 @@ async def test_piano_update_and_use(monkeypatch: pytest.MonkeyPatch) -> None:
     )
     assert send_payloads[-1].ok is True
     assert item.params.get("instrument") == "nintendo"
-    assert item.params.get("attack") == 2
-    assert item.params.get("decay") == 28
-    assert item.params.get("release") == 18
+    assert item.params.get("voiceMode") == "poly"
+    assert item.params.get("octave") == 0
+    assert item.params.get("attack") == 1
+    assert item.params.get("decay") == 24
+    assert item.params.get("release") == 15
     assert item.params.get("brightness") == 85
 
     await server._handle_message(client, json.dumps({"type": "item_use", "itemId": item.id}))
@@ -406,6 +410,21 @@ async def test_piano_update_and_use(monkeypatch: pytest.MonkeyPatch) -> None:
     assert send_payloads[-1].ok is False
     assert "instrument must be one of" in send_payloads[-1].message.lower()
 
+    await server._handle_message(
+        client,
+        json.dumps({"type": "item_update", "itemId": item.id, "params": {"voiceMode": "mono", "octave": -2}}),
+    )
+    assert send_payloads[-1].ok is True
+    assert item.params.get("voiceMode") == "mono"
+    assert item.params.get("octave") == -2
+
+    await server._handle_message(
+        client,
+        json.dumps({"type": "item_update", "itemId": item.id, "params": {"octave": 3}}),
+    )
+    assert send_payloads[-1].ok is False
+    assert "octave must be between -2 and 2" in send_payloads[-1].message.lower()
+
 
 @pytest.mark.asyncio
 async def test_piano_note_packet_broadcasts(monkeypatch: pytest.MonkeyPatch) -> None:
@@ -446,6 +465,8 @@ async def test_piano_note_packet_broadcasts(monkeypatch: pytest.MonkeyPatch) ->
     assert getattr(packet, "type", "") == "item_piano_note"
     assert getattr(packet, "itemId", "") == item.id
     assert getattr(packet, "instrument", "") == "organ"
+    assert getattr(packet, "voiceMode", "") == "poly"
+    assert getattr(packet, "octave", 999) == 0
     assert getattr(packet, "attack", -1) == 20
     assert getattr(packet, "decay", -1) == 60
     assert getattr(packet, "release", -1) == 35