Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Unaided long term average speech spectra assumed by the DSL Method in versions 4.1 (thin lines) and 5.0 (thick lines) when representing low-, moderate-, and high-level speech. See text for specific details regarding sources and overall levels.
