diff --git a/src/room/CallEventAudioRenderer.test.tsx b/src/room/CallEventAudioRenderer.test.tsx
index 9014e60b..78d08f60 100644
--- a/src/room/CallEventAudioRenderer.test.tsx
+++ b/src/room/CallEventAudioRenderer.test.tsx
@@ -8,10 +8,14 @@ Please see LICENSE in the repository root for full details.
 import { render } from "@testing-library/react";
 import { beforeEach, expect, test } from "vitest";
 import { MatrixClient } from "matrix-js-sdk/src/client";
-import { ConnectionState, RemoteParticipant, Room } from "livekit-client";
-import { of } from "rxjs";
+import { ConnectionState, Room } from "livekit-client";
+import { BehaviorSubject, of } from "rxjs";
 import { afterEach } from "node:test";
 import { act } from "react";
+import {
+  CallMembership,
+  type MatrixRTCSession,
+} from "matrix-js-sdk/src/matrixrtc";
 
 import { soundEffectVolumeSetting } from "../settings/settings";
 import {
@@ -22,6 +26,8 @@ import {
   mockMatrixRoomMember,
   mockMediaPlay,
   mockRemoteParticipant,
+  mockRtcMembership,
+  MockRTCSession,
 } from "../utils/test";
 import { E2eeType } from "../e2ee/e2eeType";
 import { CallViewModel } from "../state/CallViewModel";
@@ -30,11 +36,15 @@ import {
   MAX_PARTICIPANT_COUNT_FOR_SOUND,
 } from "./CallEventAudioRenderer";
 
-const alice = mockMatrixRoomMember({ userId: "@alice:example.org" });
-const bob = mockMatrixRoomMember({ userId: "@bob:example.org" });
-const aliceId = `${alice.userId}:AAAA`;
-const bobId = `${bob.userId}:BBBB`;
+const localRtcMember = mockRtcMembership("@carol:example.org", "CCCC");
+const local = mockMatrixRoomMember(localRtcMember);
+const aliceRtcMember = mockRtcMembership("@alice:example.org", "AAAA");
+const alice = mockMatrixRoomMember(aliceRtcMember);
+const bobRtcMember = mockRtcMembership("@bob:example.org", "BBBB");
+const bob = mockMatrixRoomMember(bobRtcMember);
 const localParticipant = mockLocalParticipant({ identity: "" });
+const aliceId = `${alice.userId}:${aliceRtcMember.deviceId}`;
+const bobId = `${bob.userId}:${bobRtcMember.deviceId}`;
 const aliceParticipant = mockRemoteParticipant({ identity: aliceId });
 const bobParticipant = mockRemoteParticipant({ identity: bobId });
 
@@ -53,20 +63,28 @@ afterEach(() => {
 
 test("plays a sound when entering a call", () => {
   const audioIsPlaying: string[] = mockMediaPlay();
-  const members = new Map([alice, bob].map((p) => [p.userId, p]));
+  const matrixRoomMembers = new Map(
+    [local, alice, bob].map((p) => [p.userId, p]),
+  );
   const remoteParticipants = of([aliceParticipant]);
   const liveKitRoom = mockLivekitRoom(
     { localParticipant },
     { remoteParticipants },
   );
+  const matrixRoom = mockMatrixRoom({
+    client: {
+      getUserId: () => localRtcMember.sender,
+      getDeviceId: () => localRtcMember.deviceId,
+    } as Partial<MatrixClient> as MatrixClient,
+    getMember: (userId) => matrixRoomMembers.get(userId) ?? null,
+  });
+
+  const session = new MockRTCSession(matrixRoom, localRtcMember, [
+    aliceRtcMember,
+  ]) as unknown as MatrixRTCSession;
 
   const vm = new CallViewModel(
-    mockMatrixRoom({
-      client: {
-        getUserId: () => "@carol:example.org",
-      } as Partial<MatrixClient> as MatrixClient,
-      getMember: (userId) => members.get(userId) ?? null,
-    }),
+    session,
     liveKitRoom,
     {
       kind: E2eeType.PER_PARTICIPANT,
@@ -84,20 +102,29 @@ test("plays a sound when entering a call", () => {
 test("plays no sound when muted", () => {
   soundEffectVolumeSetting.setValue(0);
   const audioIsPlaying: string[] = mockMediaPlay();
-  const members = new Map([alice, bob].map((p) => [p.userId, p]));
+  const matrixRoomMembers = new Map(
+    [local, alice, bob].map((p) => [p.userId, p]),
+  );
   const remoteParticipants = of([aliceParticipant, bobParticipant]);
   const liveKitRoom = mockLivekitRoom(
     { localParticipant },
     { remoteParticipants },
   );
 
+  const matrixRoom = mockMatrixRoom({
+    client: {
+      getUserId: () => localRtcMember.sender,
+      getDeviceId: () => localRtcMember.deviceId,
+    } as Partial<MatrixClient> as MatrixClient,
+    getMember: (userId) => matrixRoomMembers.get(userId) ?? null,
+  });
+
+  const session = new MockRTCSession(matrixRoom, localRtcMember, [
+    aliceRtcMember,
+  ]) as unknown as MatrixRTCSession;
+
   const vm = new CallViewModel(
-    mockMatrixRoom({
-      client: {
-        getUserId: () => "@carol:example.org",
-      } as Partial<MatrixClient> as MatrixClient,
-      getMember: (userId) => members.get(userId) ?? null,
-    }),
+    session,
     liveKitRoom,
     {
       kind: E2eeType.PER_PARTICIPANT,
@@ -112,7 +139,7 @@ test("plays no sound when muted", () => {
 
 test("plays a sound when a user joins", () => {
   const audioIsPlaying: string[] = mockMediaPlay();
-  const members = new Map([alice].map((p) => [p.userId, p]));
+  const matrixRoomMembers = new Map([local, alice].map((p) => [p.userId, p]));
   const remoteParticipants = new Map(
     [aliceParticipant].map((p) => [p.identity, p]),
   );
@@ -121,13 +148,27 @@ test("plays a sound when a user joins", () => {
     remoteParticipants,
   });
 
+  const matrixRoom = mockMatrixRoom({
+    client: {
+      getUserId: () => localRtcMember.sender,
+      getDeviceId: () => localRtcMember.deviceId,
+    } as Partial<MatrixClient> as MatrixClient,
+    getMember: (userId) => matrixRoomMembers.get(userId) ?? null,
+  });
+
+  const remoteRtcMemberships = new BehaviorSubject<CallMembership[]>([
+    aliceRtcMember,
+  ]);
+  // we give Bob an RTC session now, but no participant yet
+  const session = new MockRTCSession(
+    matrixRoom,
+    localRtcMember,
+  ).withMemberships(
+    remoteRtcMemberships.asObservable(),
+  ) as unknown as MatrixRTCSession;
+
   const vm = new CallViewModel(
-    mockMatrixRoom({
-      client: {
-        getUserId: () => "@carol:example.org",
-      } as Partial<MatrixClient> as MatrixClient,
-      getMember: (userId) => members.get(userId) ?? null,
-    }),
+    session,
     liveKitRoom as unknown as Room,
     {
       kind: E2eeType.PER_PARTICIPANT,
@@ -137,20 +178,20 @@ test("plays a sound when a user joins", () => {
   render(<CallEventAudioRenderer vm={vm} />);
 
   act(() => {
-    liveKitRoom.addParticipant(bobParticipant);
+    remoteRtcMemberships.next([aliceRtcMember, bobRtcMember]);
   });
   // Play a sound when joining a call.
   expect(audioIsPlaying).toEqual([
     // Joining the call
     enterSound,
-    // Bob leaves
+    // Bob joins
     enterSound,
   ]);
 });
 
 test("plays a sound when a user leaves", () => {
   const audioIsPlaying: string[] = mockMediaPlay();
-  const members = new Map([alice].map((p) => [p.userId, p]));
+  const matrixRoomMembers = new Map([local, alice].map((p) => [p.userId, p]));
   const remoteParticipants = new Map(
     [aliceParticipant].map((p) => [p.identity, p]),
   );
@@ -159,13 +200,25 @@ test("plays a sound when a user leaves", () => {
     remoteParticipants,
   });
 
+  const matrixRoom = mockMatrixRoom({
+    client: {
+      getUserId: () => localRtcMember.sender,
+      getDeviceId: () => localRtcMember.deviceId,
+    } as Partial<MatrixClient> as MatrixClient,
+    getMember: (userId) => matrixRoomMembers.get(userId) ?? null,
+  });
+
+  const remoteRtcMemberships = new BehaviorSubject<CallMembership[]>([
+    aliceRtcMember,
+  ]);
+
+  const session = new MockRTCSession(
+    matrixRoom,
+    localRtcMember,
+  ).withMemberships(remoteRtcMemberships) as unknown as MatrixRTCSession;
+
   const vm = new CallViewModel(
-    mockMatrixRoom({
-      client: {
-        getUserId: () => "@carol:example.org",
-      } as Partial<MatrixClient> as MatrixClient,
-      getMember: (userId) => members.get(userId) ?? null,
-    }),
+    session,
     liveKitRoom as unknown as Room,
     {
       kind: E2eeType.PER_PARTICIPANT,
@@ -175,7 +228,7 @@ test("plays a sound when a user leaves", () => {
   render(<CallEventAudioRenderer vm={vm} />);
 
   act(() => {
-    liveKitRoom.removeParticipant(aliceParticipant);
+    remoteRtcMemberships.next([]);
   });
   expect(audioIsPlaying).toEqual([
     // Joining the call
@@ -185,30 +238,45 @@ test("plays a sound when a user leaves", () => {
   ]);
 });
 
-test("plays no sound when the participant list", () => {
+test("plays no sound when the session member count is larger than the max, until decreased", () => {
   const audioIsPlaying: string[] = mockMediaPlay();
-  const members = new Map([alice].map((p) => [p.userId, p]));
-  const remoteParticipants = new Map<string, RemoteParticipant>([
-    [aliceParticipant.identity, aliceParticipant],
-    ...Array.from({ length: MAX_PARTICIPANT_COUNT_FOR_SOUND - 1 }).map<
-      [string, RemoteParticipant]
-    >((_, index) => {
-      const p = mockRemoteParticipant({ identity: `user${index}` });
-      return [p.identity, p];
-    }),
-  ]);
+  const matrixRoomMembers = new Map([local, alice].map((p) => [p.userId, p]));
+  const remoteParticipants = new Map(
+    [aliceParticipant].map((p) => [p.identity, p]),
+  );
+
+  const mockRtcMemberships: CallMembership[] = [];
+
+  for (let i = 0; i < MAX_PARTICIPANT_COUNT_FOR_SOUND; i++) {
+    mockRtcMemberships.push(
+      mockRtcMembership(`@user${i}:example.org`, `DEVICE${i}`),
+    );
+  }
+
+  const remoteRtcMemberships = new BehaviorSubject<CallMembership[]>(
+    mockRtcMemberships,
+  );
+
   const liveKitRoom = new EmittableMockLivekitRoom({
     localParticipant,
     remoteParticipants,
   });
 
+  const matrixRoom = mockMatrixRoom({
+    client: {
+      getUserId: () => localRtcMember.sender,
+      getDeviceId: () => localRtcMember.deviceId,
+    } as Partial<MatrixClient> as MatrixClient,
+    getMember: (userId) => matrixRoomMembers.get(userId) ?? null,
+  });
+
+  const session = new MockRTCSession(
+    matrixRoom,
+    localRtcMember,
+  ).withMemberships(remoteRtcMemberships) as unknown as MatrixRTCSession;
+
   const vm = new CallViewModel(
-    mockMatrixRoom({
-      client: {
-        getUserId: () => "@carol:example.org",
-      } as Partial<MatrixClient> as MatrixClient,
-      getMember: (userId) => members.get(userId) ?? null,
-    }),
+    session,
     liveKitRoom as unknown as Room,
     {
       kind: E2eeType.PER_PARTICIPANT,
@@ -217,9 +285,11 @@ test("plays no sound when the participant list", () => {
   );
   render(<CallEventAudioRenderer vm={vm} />);
   expect(audioIsPlaying).toEqual([]);
-  // When the count drops
+  // When the count drops to the max we should play the leave sound
   act(() => {
-    liveKitRoom.removeParticipant(aliceParticipant);
+    remoteRtcMemberships.next(
+      mockRtcMemberships.slice(0, MAX_PARTICIPANT_COUNT_FOR_SOUND - 1),
+    );
   });
   expect(audioIsPlaying).toEqual([leaveSound]);
 });