Communications headset speech-based gain control

1. A communications headset comprising:

a first earpiece comprising:

a first casing; and

a first acoustic driver disposed therein;

a first talk-through microphone carried by structure of the communications headset and acoustically coupled to an environment external to the communications headset;

an audio circuit coupled to the first acoustic driver and the first talk-through microphone, the audio circuit comprising a first talk-through circuit receiving a signal representing sounds detected by the first talk-through microphone and providing its output to the first acoustic driver;

a communications microphone positioned relative to the first casing of the earpiece towards the vicinity of a mouth of a user of the communications headset, wherein the communications microphone is noise-canceling microphone,

wherein a gain of the signal representing sounds detected by the first talk-through microphone is reduced by a component of the first talk-through circuit in response to an instance of speech by a user of the communications headset being detected by the communications microphone, the first talk-through circuit comprising:

a first audio amplifier to drive the acoustic driver with the output of the first talk-through circuit;

a first envelope detector coupled to the output of the first audio amplifier to integrate peaks in a signal output by the first audio amplifier in driving the acoustic driver;

a first controllable attenuator interposed between the first talk-through microphone and an input of the first audio amplifier; and

the first envelope detector and the first controllable attenuator cooperate to form a first closed-loop compressor to limit an amplitude of the signal output by the first audio amplifier in response to the signal output by the first audio amplifier exceeding a predetermined threshold.

2. The communications headset of claim 1 , wherein:

the audio circuit further comprises a first ANR circuit receiving a signal representing noise sounds detected in the environment external to the communications headset, deriving anti-noise sounds, and providing the anti-noise sounds to the first acoustic driver; and

a gain of the signal representing noise sounds is reduced by a component of the first ANR circuit in response to an instance of speech by a user of the communications headset being detected by the communications microphone.

3. The communications headset of claim 2 , wherein the noise sounds are detected by the first talk-through microphone.

4. The communications headset of claim 2 , further comprising a first ANR microphone coupled to the audio circuit, and wherein the noise sounds are detected by the first ANR microphone.

5. The communications headset of claim 1 , further comprising:

a second earpiece comprising:

a second casing; and

a second acoustic driver disposed therein;

a second talk-through microphone carried by structure of the communications headset and acoustically coupled to an environment external to the communications headset; and

wherein:

the audio circuit is further coupled to the second acoustic driver and the second talk-through microphone;

the audio circuit further comprises a second talk-through circuit receiving a signal representing sounds detected by the second talk-through microphone and providing its output to the second acoustic driver; and

a gain of the signal representing sounds detected by the second talk-through microphone is reduced by a component of the second talk-through circuit in response to an instance of speech by a user of the communications headset being detected by the communications microphone.

6. The communications headset of claim 1 , wherein the first controllable attenuator comprises a voltage-controlled attenuator, and

the audio circuit further comprises:

an amplifier coupled to the communications microphone; and wherein the first envelope detector is coupled to an output of the amplifier and coupled to a gain control input of the first controllable attenuator; and

the first controllable attenuator is the component of the first talk-through circuit reducing the gain of the signal representing sounds detected by the first talk-through microphone.

7. A method of controlling sounds acoustically output by an acoustic driver of a communications headset to an ear of a user of the communications headset, comprising:

detecting speech sounds of a user of the communications headset using a noise-canceling communications microphone of the communications headset;

integrating peaks of a signal output by the communications microphone, wherein an envelope detector coupled to the communications microphone is employed to perform the integrating of the peaks;

reducing a gain of a signal representing sounds detected by a talk-through microphone of the communications headset in response to detecting the speech sounds of the user of the communications headset such that an amplitude of sounds detected by the talk-through microphone that are acoustically output by the acoustic driver is reduced; and

controlling the reducing of the gain with the results of the integrating of the peaks, wherein a component of a talk-through circuit to which the talk-through microphone and the acoustic driver are coupled is employed to reduce the gain of the signal representing sounds detected by the talk-through microphone in a manner in which the combination of the envelope detector and the component of the talk-through circuit form an open-loop compressor.

8. The method of claim 7 , wherein the component of the talk-through circuit is a voltage-controlled attenuator comprising a gain control input coupled to the envelope detector.

9. The method of claim 7 , wherein the component of the talk-through circuit is an audio amplifier comprising a gain control input coupled to the envelope detector.