Specify getFloatTimeDomainData() encoding range (#40544)

Author: Josh-Cena

files/en-us/web/api/analysernode/getfloattimedomaindata/index.md

@@ -10,6 +10,8 @@ browser-compat: api.AnalyserNode.getFloatTimeDomainData
 
 The **`getFloatTimeDomainData()`** method of the {{ domxref("AnalyserNode") }} Interface copies the current waveform, or time-domain, data into a {{jsxref("Float32Array")}} array passed into it. Each array value is a _sample_, the magnitude of the signal at a particular time.
 
+The waveform is represented as PCM data, which has a nominal range of -1.0 to 1.0, but values can exceed the range such as when down-mixing stereo to mono.
+
 ## Syntax
 
 ```js-nolint