To begin your exploration of spatial audio, open up the monitors using your computer keyboard (or mouse). Move the sliders around and listen for changes in balance and width. Drag the sound sources on the stage itself. The idea is to be able to audition and visualize what you are doing when stereo panning is heard as a mono or side channel view.
To turn monitors on/off just push Space bar. It will engage the audio engine and start updating the meters visually. If you don’t like moving the mouse around you can tap Enter on a button as well. To switch from one listen mode to another, we have keyboard shortcuts. They is all within reach of your hands while adjusting sound.
How to Use the Tool
Adjusting the Scene selector changes the underlying audio material. Try Wide chord pad which provides a full, sustained sound that exposes phase issues well. Double tracked pluck provide a rhythmic element with clear stereo separation. Split percussion presents a series of percussive hits spread out over the field. Coherent phase probe test cancellation behaviour using perfectly correlated signals.
To adjust the Pan position, drag either the Source A or Source B icon horizontally around the Stage area. To adjust the stereo width, pull on the stage width slider to change how far apart the two sources are. You can adjust the center balance to move both sources to the left or right channel with the slider. All of these settings work together and create the stereo image that is heard out of your headphones or speakers.
You can toggle between Restore L/R field, Sum, and Inspect modes to change how the signal is routed. The restore plays the standard stereo signal with equal power panning. The sum computes the average of both channels to display what would happen if you folded the mix down to mono. The inspect isolates the difference signal, and shows the info that only lives in the stereo width.
In the Readout section check out the audible span, routing correlation, mono fold delta. The audible span is the percentage width of the stereo image. The routing correlation lets you know how mathematically similar the left and right channels are. The mono fold delta tells you the level change in decibels that occurs by toggling between mono and stereo. Use these measures to judge if your mix is strong.
Use Vector trace to see how your current signal’s energy is being distributed with this view. As you play, watch the bars respond in realtime to indicate whether you have more side or center information. If you see a wide image, it has pushed the energy toward the edges. A centered image will display higher energy in the center of the trace. The visual feedback adds to what you’re hearing as an audio cue.
Pressing D will isolate the Side channel, which lets you inspect it in more detail. Pressing S puts you back in Stereo as normal. Pressing M puts you in Mono immediately. Pressing P will flip the polarity on source B (useful when checking for phase coherence). Pressing X swaps the positions of source A and source B while retaining width.
Flip the phase of the second source by clicking Invert B polarity. It’s especially useful on this scene using the Coherent phase probe. The side signal will be reinforced while the mono sum will cancel out a lot when inverted. You can see here that phase alignment not only matters for mono compatibility but also overall volume.
The Master monitor lets you adjust the output volume with its slider. Make it easy on your ears, and keep it at a comfortabley level so you can hear subtle changes in width and balance. To give yourself more space for metering and seeing the stage, click Fullscreen. Click Help for a quick refresher on the controls and how they work.
Drag source A and B around, listening for that stereo width when they are pulled apart. When you switch to mono, you’ll notice both sources drop in level along with what’s missing from the center. The correlation meter will help you locate the sweet spot of being wide but mono safe. Toggle polarity and learn how your out-of-phase signals sound in a mix.
The simulator also provides a way of developing a naturaly understanding of summing behavior and panning laws. It allows you to test out your mixes from side views, mono, and more. The visual and sound feedback work together to help you better understand concepts like spatial sound. Spend some time exploring the controls and scenes and notice how they interact with one another.
Open up the monitors and select a scene you find interesting. Then move the sources around until the stereo width sounds right to you. Check the meters to make sure the numbers match. Change back and forth using the keyboard shortcuts as needed when adjusting. Have fun with learning how stereo imaging can affect what you hear.