diff --git a/js/demo/testing/model/AmplitudeModulatorDemo.ts b/js/demo/testing/model/AmplitudeModulatorDemo.ts
index 4af073b7..c217b655 100644
--- a/js/demo/testing/model/AmplitudeModulatorDemo.ts
+++ b/js/demo/testing/model/AmplitudeModulatorDemo.ts
@@ -1,5 +1,13 @@
 // Copyright 2020-2022, University of Colorado Boulder
 
+/**
+ * Demo and test harness for the AmplitudeModulator class.  This creates several sound loops and routes them through
+ * an amplitude modulator instance.  It also provides the properties that can be manipulated in the view to change the
+ * attributes of the modulation.
+ *
+ * @author John Blanco (PhET Interactive Simulations)
+ */
+
 import saturatedSineLoop220Hz_mp3 from '../../../../sounds/saturatedSineLoop220Hz_mp3.js';
 import windsLoopC3Oscilloscope_mp3 from '../../../../sounds/demo-and-test/windsLoopC3Oscilloscope_mp3.js';
 import windsLoopMiddleCOscilloscope_mp3 from '../../../../sounds/demo-and-test/windsLoopMiddleCOscilloscope_mp3.js';
@@ -9,18 +17,11 @@ import SoundGenerator, { SoundGeneratorOptions } from '../../../sound-generators
 import tambo from '../../../tambo.js';
 import NumberProperty from '../../../../../axon/js/NumberProperty.js';
 
-/**
- * Demo and test harness for the AmplitudeModulator class.  This creates several sound loops and routes them through
- * an amplitude modulator instance.  It also provides the properties that can be manipulated in the view to change the
- * attributes of the modulation.
- */
-
-
 class AmplitudeModulatorDemo extends SoundGenerator {
 
   public readonly amplitudeModulator: AmplitudeModulator;
 
-  constructor( sourceSoundIndexProperty: NumberProperty, options: SoundGeneratorOptions ) {
+  constructor( sourceSoundIndexProperty: NumberProperty, options?: SoundGeneratorOptions ) {
 
     super( options );
 
diff --git a/js/demo/testing/view/AmplitudeModulatorDemoNode.ts b/js/demo/testing/view/AmplitudeModulatorDemoNode.ts
index d6b161aa..89a2dc99 100644
--- a/js/demo/testing/view/AmplitudeModulatorDemoNode.ts
+++ b/js/demo/testing/view/AmplitudeModulatorDemoNode.ts
@@ -1,14 +1,17 @@
 // Copyright 2020-2021, University of Colorado Boulder
 
-// @ts-nocheck
+/**
+ * View portion of the demo and test harness for the AmplitudeModulator class.
+ *
+ * @author John Blanco (PhET Interactive Simulations)
+ */
 
+import BooleanProperty from '../../../../../axon/js/BooleanProperty.js';
 import NumberProperty from '../../../../../axon/js/NumberProperty.js';
 import Range from '../../../../../dot/js/Range.js';
-import merge from '../../../../../phet-core/js/merge.js';
+import optionize from '../../../../../phet-core/js/optionize.js';
 import PhetFont from '../../../../../scenery-phet/js/PhetFont.js';
-import { HBox } from '../../../../../scenery/js/imports.js';
-import { Text } from '../../../../../scenery/js/imports.js';
-import { VBox } from '../../../../../scenery/js/imports.js';
+import { HBox, Text, VBox, VBoxOptions } from '../../../../../scenery/js/imports.js';
 import AquaRadioButtonGroup from '../../../../../sun/js/AquaRadioButtonGroup.js';
 import Checkbox from '../../../../../sun/js/Checkbox.js';
 import HSlider from '../../../../../sun/js/HSlider.js';
@@ -16,15 +19,15 @@ import soundManager from '../../../soundManager.js';
 import tambo from '../../../tambo.js';
 import AmplitudeModulatorDemo from '../model/AmplitudeModulatorDemo.js';
 
+type SelfOptions = {};
+export type AmplitudeModulatorDemoNodeOptions = SelfOptions & VBoxOptions;
+
 // constants
 const LABEL_FONT = new PhetFont( 16 );
 
-/**
- * View portion of the demo and test harness for the AmplitudeModulator class.
- */
 class AmplitudeModulatorDemoNode extends VBox {
 
-  constructor( options ) {
+  constructor( providedOptions: AmplitudeModulatorDemoNodeOptions ) {
 
     const soundSourceRadioButtonItems = [
       {
@@ -62,7 +65,7 @@ class AmplitudeModulatorDemoNode extends VBox {
     // LFO enabled control
     const lfoEnabled = new Checkbox(
       new Text( 'LFO Enabled', { font: LABEL_FONT } ),
-      amplitudeModulatorDemo.amplitudeModulator.enabledProperty,
+      amplitudeModulatorDemo.amplitudeModulator.enabledProperty as BooleanProperty,
       { boxWidth: 16 }
     );
 
@@ -120,12 +123,11 @@ class AmplitudeModulatorDemoNode extends VBox {
       spacing: 5
     } );
 
-
-    super( merge( {
+    super( optionize<AmplitudeModulatorDemoNodeOptions, SelfOptions, VBoxOptions>( {
       children: [ soundIndexSelectorVBox, lfoEnabled, frequencyControlHBox, depthControlHBox, waveformSelectorVBox ],
       spacing: 15,
       align: 'left'
-    }, options ) );
+    }, providedOptions ) );
   }
 }
 
diff --git a/js/demo/testing/view/CompositeSoundClipTestNode.ts b/js/demo/testing/view/CompositeSoundClipTestNode.ts
index 9394c1fc..75fc9e9a 100644
--- a/js/demo/testing/view/CompositeSoundClipTestNode.ts
+++ b/js/demo/testing/view/CompositeSoundClipTestNode.ts
@@ -1,7 +1,5 @@
 // Copyright 2020-2022, University of Colorado Boulder
 
-// @ts-nocheck
-
 /**
  * Test and demo of the CompositeSoundClip.
  *
@@ -10,7 +8,7 @@
 
 import merge from '../../../../../phet-core/js/merge.js';
 import PhetFont from '../../../../../scenery-phet/js/PhetFont.js';
-import { VBox } from '../../../../../scenery/js/imports.js';
+import { VBox, VBoxOptions } from '../../../../../scenery/js/imports.js';
 import TextPushButton from '../../../../../sun/js/buttons/TextPushButton.js';
 import brightMarimba_mp3 from '../../../../sounds/brightMarimba_mp3.js';
 import loonCall_mp3 from '../../../../sounds/demo-and-test/loonCall_mp3.js';
@@ -21,10 +19,10 @@ import tambo from '../../../tambo.js';
 
 class CompositeSoundClipTestNode extends VBox {
 
-  /**
-   * @param {Object} [options]
-   */
-  constructor( options ) {
+  // dispose function
+  private readonly disposeCompositeSoundClipTestNode: () => void;
+
+  constructor( options: VBoxOptions ) {
 
     // sound clips to be played
     const compositeSoundClip = new CompositeSoundClip( [
diff --git a/js/demo/testing/view/ContinuousPropertySoundGeneratorTestNode.ts b/js/demo/testing/view/ContinuousPropertySoundGeneratorTestNode.ts
index 2b4d9e08..89f442a1 100644
--- a/js/demo/testing/view/ContinuousPropertySoundGeneratorTestNode.ts
+++ b/js/demo/testing/view/ContinuousPropertySoundGeneratorTestNode.ts
@@ -1,7 +1,5 @@
 // Copyright 2020-2022, University of Colorado Boulder
 
-// @ts-nocheck
-
 /**
  * Test and demo of the ContinuousPropertySoundGenerator.
  *
@@ -14,8 +12,7 @@ import NumberProperty from '../../../../../axon/js/NumberProperty.js';
 import Range from '../../../../../dot/js/Range.js';
 import merge from '../../../../../phet-core/js/merge.js';
 import NumberControl from '../../../../../scenery-phet/js/NumberControl.js';
-import { Text } from '../../../../../scenery/js/imports.js';
-import { VBox } from '../../../../../scenery/js/imports.js';
+import { Text, VBox, VBoxOptions } from '../../../../../scenery/js/imports.js';
 import Checkbox from '../../../../../sun/js/Checkbox.js';
 import Panel from '../../../../../sun/js/Panel.js';
 import saturatedSineLoop220Hz_mp3 from '../../../../sounds/saturatedSineLoop220Hz_mp3.js';
@@ -25,31 +22,36 @@ import windsLoopMiddleCOscilloscope_mp3 from '../../../../sounds/demo-and-test/w
 import ContinuousPropertySoundGenerator from '../../../sound-generators/ContinuousPropertySoundGenerator.js';
 import soundManager from '../../../soundManager.js';
 import tambo from '../../../tambo.js';
+import Emitter from '../../../../../axon/js/Emitter.js';
+import WrappedAudioBuffer from '../../../WrappedAudioBuffer.js';
+
+type SelfOptions = {};
+export type ContinuousPropertySoundGeneratorTestNodeOptions = SelfOptions & VBoxOptions;
 
 class ContinuousPropertySoundGeneratorTestNode extends VBox {
 
-  /**
-   * @param {Emitter} stepEmitter
-   * @param {Object} [options]
-   */
-  constructor( stepEmitter, options ) {
+  // dispose function
+  private readonly disposeContinuousPropertySoundGeneratorTestNode: () => void;
+
+  constructor( stepEmitter: Emitter<[ number ]>, providedOptions: ContinuousPropertySoundGeneratorTestNodeOptions ) {
 
     // keep track of listeners added to the step emitter so that they can be disposed
-    const stepListeners = [];
+    const stepListeners: ( ( dt: number ) => void )[] = [];
 
     // creates a panel that demonstrates a ContinuousPropertySoundGenerator
-    const createTester = ( sound, max ) => {
+    const createTester = ( sound: WrappedAudioBuffer, max: number ) => {
       const numberProperty = new NumberProperty( 5 );
       const range = new Range( 1, 10 );
       const continuousPropertySoundGenerator = new ContinuousPropertySoundGenerator(
         numberProperty,
         sound,
+        // @ts-ignore
         range
       );
       soundManager.addSoundGenerator( continuousPropertySoundGenerator );
       const isOscillatingProperty = new BooleanProperty( false );
       let phase = 0;
-      const stepListener = dt => {
+      const stepListener = ( dt: number ) => {
         if ( isOscillatingProperty.value ) {
           numberProperty.value = ( max * Math.sin( Date.now() / 1000 - phase ) + 1 ) * ( range.max - range.min ) / 2 + range.min;
         }
@@ -81,9 +83,9 @@ class ContinuousPropertySoundGeneratorTestNode extends VBox {
       ],
       spacing: 15,
       align: 'left'
-    }, options ) );
+    }, providedOptions ) );
 
-    // @private - for memory cleanup
+    // define dispose function for memory cleanup
     this.disposeContinuousPropertySoundGeneratorTestNode = () => {
       stepListeners.forEach( listener => {
         stepEmitter.removeListener( listener );
diff --git a/js/demo/testing/view/RemoveAndDisposeSoundGeneratorsTestPanel.ts b/js/demo/testing/view/RemoveAndDisposeSoundGeneratorsTestPanel.ts
index f0b8a2c9..c02af826 100644
--- a/js/demo/testing/view/RemoveAndDisposeSoundGeneratorsTestPanel.ts
+++ b/js/demo/testing/view/RemoveAndDisposeSoundGeneratorsTestPanel.ts
@@ -1,7 +1,5 @@
 // Copyright 2018-2022, University of Colorado Boulder
 
-// @ts-nocheck
-
 /**
  * a panel that contains controls used to exercise the addition, removal, and disposal of sound generators
  *
@@ -12,23 +10,28 @@ import createObservableArray from '../../../../../axon/js/createObservableArray.
 import Property from '../../../../../axon/js/Property.js';
 import stepTimer from '../../../../../axon/js/stepTimer.js';
 import dotRandom from '../../../../../dot/js/dotRandom.js';
-import merge from '../../../../../phet-core/js/merge.js';
+import optionize from '../../../../../phet-core/js/optionize.js';
 import StringUtils from '../../../../../phetcommon/js/util/StringUtils.js';
 import PhetFont from '../../../../../scenery-phet/js/PhetFont.js';
-import { HBox } from '../../../../../scenery/js/imports.js';
-import { Node } from '../../../../../scenery/js/imports.js';
-import { Text } from '../../../../../scenery/js/imports.js';
-import { VBox } from '../../../../../scenery/js/imports.js';
+import { HBox, Node, Text, VBox } from '../../../../../scenery/js/imports.js';
 import TextPushButton from '../../../../../sun/js/buttons/TextPushButton.js';
 import ComboBox from '../../../../../sun/js/ComboBox.js';
 import ComboBoxItem from '../../../../../sun/js/ComboBoxItem.js';
-import Panel from '../../../../../sun/js/Panel.js';
+import Panel, { PanelOptions } from '../../../../../sun/js/Panel.js';
 import birdCall_mp3 from '../../../../sounds/demo-and-test/birdCall_mp3.js';
 import cricketsLoop_mp3 from '../../../../sounds/demo-and-test/cricketsLoop_mp3.js';
 import PitchedPopGenerator from '../../../sound-generators/PitchedPopGenerator.js';
 import SoundClip from '../../../sound-generators/SoundClip.js';
 import soundManager from '../../../soundManager.js';
 import tambo from '../../../tambo.js';
+import SoundGenerator from '../../../sound-generators/SoundGenerator.js';
+
+type SelfOptions = {};
+export type RemoveAndDisposeSoundGeneratorsTestPanelOptions = SelfOptions & PanelOptions;
+type SoundGeneratorComboBoxItemInfo = {
+  comboBoxItemName: string;
+  createSoundGenerator: () => SoundGenerator;
+}
 
 // constants
 const BUTTON_FONT = new PhetFont( 18 );
@@ -37,37 +40,42 @@ const TOTAL_ADDED_TEMPLATE = 'Total Added: {{numSoundGenerators}}';
 const ADD_BUTTON_COLOR = '#C0D890';
 
 // info needed for selecting and using different sound generators from the combo box
-const SOUND_GENERATOR_INFO = {
-  recordedOneShot: {
-    comboBoxName: 'Recorded one shot',
-    createSoundGenerator: () => new SoundClip( birdCall_mp3 )
-  },
-  recordedLoop: {
-    comboBoxName: 'Recorded loop',
-    createSoundGenerator: () => new SoundClip( cricketsLoop_mp3, { loop: true } )
-  },
-  synthesizedSound: {
-    comboBoxName: 'Synthesized sound',
-    createSoundGenerator: () => new PitchedPopGenerator( { numPopGenerators: 2 } )
-  }
-};
+const SOUND_GENERATOR_INFO = new Map<string, SoundGeneratorComboBoxItemInfo>( [
+  [
+    'recordedOneShot',
+    {
+      comboBoxItemName: 'Recorded one shot',
+      createSoundGenerator: () => new SoundClip( birdCall_mp3 )
+    }
+  ],
+  [
+    'recordedLoop',
+    {
+      comboBoxItemName: 'Recorded loop',
+      createSoundGenerator: () => new SoundClip( cricketsLoop_mp3, { loop: true } )
+    }
+  ],
+  [
+    'synthesizedSound',
+    {
+      comboBoxItemName: 'Synthesized sound',
+      createSoundGenerator: () => new PitchedPopGenerator( { numPopGenerators: 2 } )
+    }
+  ]
+] );
 
 class RemoveAndDisposeSoundGeneratorsTestPanel extends Panel {
 
-  /**
-   * @param {Object} [options]
-   * @constructor
-   */
-  constructor( options ) {
+  constructor( providedOptions: RemoveAndDisposeSoundGeneratorsTestPanelOptions ) {
 
-    options = merge( {
+    const options = optionize<RemoveAndDisposeSoundGeneratorsTestPanelOptions, SelfOptions, PanelOptions>( {
       fill: '#f5d3b3',
       xMargin: 14,
       yMargin: 14
-    }, options );
+    }, providedOptions );
 
     // array of sound generators that have been added and not yet removed and disposed
-    const soundGenerators = createObservableArray();
+    const soundGenerators = createObservableArray<SoundGenerator>();
 
     // node where the content goes, needed so that ComboBox will have a good place to put its list
     const panelContentNode = new Node();
@@ -77,11 +85,11 @@ class RemoveAndDisposeSoundGeneratorsTestPanel extends Panel {
       font: new PhetFont( { size: 18, weight: 'bold' } )
     } );
 
-    // create the combo box for selecting the type of sound generator to add
-    const comboBoxItems = [];
-    _.keys( SOUND_GENERATOR_INFO ).forEach( soundGeneratorKey => {
+    // Create the combo box for selecting the type of sound generator to add.
+    const comboBoxItems: ComboBoxItem<string>[] = [];
+    SOUND_GENERATOR_INFO.forEach( ( soundGenerator, soundGeneratorKey ) => {
       comboBoxItems.push( new ComboBoxItem(
-        new Text( SOUND_GENERATOR_INFO[ soundGeneratorKey ].comboBoxName, { font: COMBO_BOX_FONT } ),
+        new Text( soundGenerator.comboBoxItemName, { font: COMBO_BOX_FONT } ),
         soundGeneratorKey
       ) );
     } );
@@ -97,9 +105,9 @@ class RemoveAndDisposeSoundGeneratorsTestPanel extends Panel {
       spacing: 7
     } );
 
-    function addSoundGenerators( numToAdd ) {
-      _.times( numToAdd, () => {
-        const soundGenerator = SOUND_GENERATOR_INFO[ selectedSoundGeneratorTypeProperty.value ].createSoundGenerator();
+    function addSoundGenerators( numberToAdd: number ) {
+      _.times( numberToAdd, () => {
+        const soundGenerator = SOUND_GENERATOR_INFO.get( selectedSoundGeneratorTypeProperty.value )!.createSoundGenerator();
         soundManager.addSoundGenerator( soundGenerator );
         soundGenerators.push( soundGenerator );
       } );
diff --git a/js/demo/testing/view/SoundClipChordTestNode.ts b/js/demo/testing/view/SoundClipChordTestNode.ts
index 5872ae9d..afa23ed1 100644
--- a/js/demo/testing/view/SoundClipChordTestNode.ts
+++ b/js/demo/testing/view/SoundClipChordTestNode.ts
@@ -1,28 +1,29 @@
 // Copyright 2020-2022, University of Colorado Boulder
 
-// @ts-nocheck
+/**
+ * Test and demo of the SoundClipChord.
+ *
+ * @author Michael Kauzamann (PhET Interactive Simulations)
+ */
 
-import merge from '../../../../../phet-core/js/merge.js';
 import PhetFont from '../../../../../scenery-phet/js/PhetFont.js';
-import { VBox } from '../../../../../scenery/js/imports.js';
+import { VBox, VBoxOptions } from '../../../../../scenery/js/imports.js';
 import TextPushButton from '../../../../../sun/js/buttons/TextPushButton.js';
 import brightMarimba_mp3 from '../../../../sounds/brightMarimba_mp3.js';
 import SoundPlayer from '../../../SoundPlayer.js';
 import SoundClipChord from '../../../sound-generators/SoundClipChord.js';
 import soundManager from '../../../soundManager.js';
 import tambo from '../../../tambo.js';
+import optionize from '../../../../../phet-core/js/optionize.js';
+
+type SelfOptions = {};
+export type SoundClipChordTestNodeOptions = SelfOptions & VBoxOptions;
 
-/**
- * Test and demo of the SoundClipChord.
- *
- * @author Michael Kauzamann (PhET Interactive Simulations)
- */
 class SoundClipChordTestNode extends VBox {
 
-  /**
-   * @param {Object} [options]
-   */
-  constructor( options ) {
+  private readonly disposeSoundClipChordTestNode: () => void;
+
+  constructor( providedOptions: SoundClipChordTestNodeOptions ) {
 
     // sound clips to be played
     const chordSoundClipChord = new SoundClipChord( brightMarimba_mp3 );
@@ -46,10 +47,10 @@ class SoundClipChordTestNode extends VBox {
       listener: () => { arpeggioSoundClipChord.play(); }
     } );
 
-    super( merge( {
+    super( optionize<SoundClipChordTestNodeOptions, SelfOptions, VBoxOptions>( {
       children: [ playBasicSoundButton, playEnhancedSoundButton ],
       spacing: 20
-    }, options ) );
+    }, providedOptions ) );
 
     // @private - dispose function
     this.disposeSoundClipChordTestNode = () => {
@@ -70,4 +71,5 @@ class SoundClipChordTestNode extends VBox {
 }
 
 tambo.register( 'SoundClipChordTestNode', SoundClipChordTestNode );
+
 export default SoundClipChordTestNode;
\ No newline at end of file
diff --git a/js/demo/testing/view/TestingScreenView.ts b/js/demo/testing/view/TestingScreenView.ts
index 8895080a..62466d0e 100644
--- a/js/demo/testing/view/TestingScreenView.ts
+++ b/js/demo/testing/view/TestingScreenView.ts
@@ -1,7 +1,5 @@
 // Copyright 2018-2022, University of Colorado Boulder
 
-// @ts-nocheck
-
 /**
  * view for a screen that allows testing and demonstration of various sound components and behaviors
  *
@@ -15,10 +13,10 @@ import stepTimer from '../../../../../axon/js/stepTimer.js';
 import merge from '../../../../../phet-core/js/merge.js';
 import ResetAllButton from '../../../../../scenery-phet/js/buttons/ResetAllButton.js';
 import PhetFont from '../../../../../scenery-phet/js/PhetFont.js';
-import { HBox, Image, Node, Text, VBox } from '../../../../../scenery/js/imports.js';
+import { HBox, Image, Node, NodeOptions, Text, VBox, VBoxOptions } from '../../../../../scenery/js/imports.js';
 import TextPushButton from '../../../../../sun/js/buttons/TextPushButton.js';
 import Checkbox from '../../../../../sun/js/Checkbox.js';
-import DemosScreenView from '../../../../../sun/js/demo/DemosScreenView.js';
+import DemosScreenView, { SunDemo } from '../../../../../sun/js/demo/DemosScreenView.js';
 import Panel from '../../../../../sun/js/Panel.js';
 import lightning_png from '../../../../images/lightning_png.js';
 import checkboxChecked_mp3 from '../../../../sounds/checkboxChecked_mp3.js';
@@ -37,6 +35,8 @@ import CompositeSoundClipTestNode from './CompositeSoundClipTestNode.js';
 import ContinuousPropertySoundGeneratorTestNode from './ContinuousPropertySoundGeneratorTestNode.js';
 import RemoveAndDisposeSoundGeneratorsTestPanel from './RemoveAndDisposeSoundGeneratorsTestPanel.js';
 import SoundClipChordTestNode from './SoundClipChordTestNode.js';
+import Bounds2 from '../../../../../dot/js/Bounds2.js';
+import { TimerListener } from '../../../../../axon/js/Timer.js';
 
 // constants
 const CHECKBOX_SIZE = 16;
@@ -45,6 +45,8 @@ const LIGHTNING_SHOWN_TIME = 0.750; // in seconds
 
 class TestingScreenView extends DemosScreenView {
 
+  private readonly stepEmitter: Emitter<[ number ]>;
+
   /**
    * @constructor
    */
@@ -53,52 +55,52 @@ class TestingScreenView extends DemosScreenView {
     const resetInProgressProperty = new BooleanProperty( false );
 
     // demo items, selected via the combo box in the parent class
-    const demos = [
+    const demos: SunDemo[] = [
       {
         label: 'AmplitudeModulatorTest',
-        createNode: layoutBounds => new AmplitudeModulatorDemoNode( {
+        createNode: ( layoutBounds: Bounds2 ) => new AmplitudeModulatorDemoNode( {
           center: layoutBounds.center
         } )
       },
       {
         label: 'AdditionalAudioNodesTestNode',
-        createNode: layoutBounds => new AdditionalAudioNodesTestNode( {
+        createNode: ( layoutBounds: Bounds2 ) => new AdditionalAudioNodesTestNode( {
           center: layoutBounds.center
         } )
       },
       {
         label: 'BasicAndEnhancedSounds',
-        createNode: layoutBounds => new BasicAndEnhancedSoundTestNode( {
+        createNode: ( layoutBounds: Bounds2 ) => new BasicAndEnhancedSoundTestNode( {
           center: layoutBounds.center
         } )
       },
       {
         label: 'ContinuousPropertySoundGeneratorTest',
-        createNode: layoutBounds => new ContinuousPropertySoundGeneratorTestNode( this.stepEmitter, {
+        createNode: ( layoutBounds: Bounds2 ) => new ContinuousPropertySoundGeneratorTestNode( this.stepEmitter, {
           center: layoutBounds.center
         } )
       },
       {
         label: 'CompositeSoundClipTestNode',
-        createNode: layoutBounds => new CompositeSoundClipTestNode( {
+        createNode: ( layoutBounds: Bounds2 ) => new CompositeSoundClipTestNode( {
           center: layoutBounds.center
         } )
       },
       {
         label: 'RemoveAndDisposeSoundGenerators',
-        createNode: layoutBounds => new RemoveAndDisposeSoundGeneratorsTestPanel( {
+        createNode: ( layoutBounds: Bounds2 ) => new RemoveAndDisposeSoundGeneratorsTestPanel( {
           center: layoutBounds.center
         } )
       },
       {
         label: 'LongSoundTest',
-        createNode: layoutBounds => new LongSoundTestPanel( resetInProgressProperty, {
+        createNode: ( layoutBounds: Bounds2 ) => new LongSoundTestPanel( resetInProgressProperty, {
           center: layoutBounds.center
         } )
       },
       {
         label: 'SoundClipChordTestNode',
-        createNode: layoutBounds => new SoundClipChordTestNode( {
+        createNode: ( layoutBounds: Bounds2 ) => new SoundClipChordTestNode( {
           center: layoutBounds.center
         } )
       }
@@ -123,12 +125,7 @@ class TestingScreenView extends DemosScreenView {
     this.addChild( resetAllButton );
   }
 
-  /**
-   * @override
-   * @param {number} dt
-   * @public
-   */
-  step( dt ) {
+  public step( dt: number ) {
     this.stepEmitter.emit( dt );
   }
 }
@@ -138,7 +135,9 @@ class TestingScreenView extends DemosScreenView {
  */
 class BasicAndEnhancedSoundTestNode extends VBox {
 
-  constructor( options ) {
+  private readonly disposeBasicAndEnhancedSoundTestNode: () => void;
+
+  constructor( options: VBoxOptions ) {
 
     // sound clips to be played
     const loonCallSoundClip = new SoundClip( loonCall_mp3 );
@@ -191,7 +190,9 @@ class BasicAndEnhancedSoundTestNode extends VBox {
  */
 class AdditionalAudioNodesTestNode extends VBox {
 
-  constructor( options ) {
+  private readonly disposeBasicAndEnhancedSoundTestNode: () => void;
+
+  constructor( options: VBoxOptions ) {
 
     // convolver node, which will be used to create the reverb effect
     const convolver = phetAudioContext.createConvolver();
@@ -265,11 +266,13 @@ class AdditionalAudioNodesTestNode extends VBox {
  */
 class LongSoundTestPanel extends Node {
 
-  constructor( resetInProgressProperty, options ) {
+  private readonly disposeLongSoundTestPanel: () => void;
+
+  constructor( resetInProgressProperty: BooleanProperty, options: NodeOptions ) {
 
     // internal state variables
     const lightningBoltVisibleProperty = new BooleanProperty( false );
-    let lightningBoltVisibleTimeout = null;
+    let lightningBoltVisibleTimeout: null | TimerListener = null;
 
     // timeout function
     const timeoutFiredListener = () => {
@@ -378,4 +381,5 @@ class LongSoundTestPanel extends Node {
 }
 
 tambo.register( 'TestingScreenView', TestingScreenView );
+
 export default TestingScreenView;
\ No newline at end of file