A method for processing multi-channel audio streams comprising: summing and then combining signal processing inputs from a plurality of far-end channels (350A-N) thereby to provide a combined signal-processing input; receiving at a first single-channel audio component located at a near-end channel of an audio signal transmission path, the combined signal-processing input, the first single-channel audio component being one of a group of first single-channel audio components (1 - M) each located at a different near-end channel (300A-300M) of the signal transmission path, each receiving the combined signal-processing input, and each of which is either a gain control component or an echo control component; processing an audio signal at the first single-channel audio component using the combined signal-processing input to produce a processed audio signal; sending the processed audio signal from the first single-channel audio component to a second single-channel audio component located at the near-end channel, the second single-channel audio component being one of a group of second single-channel audio components each located at a different near-end channel (300A-300M) of the signal transmission path, each receiving the combined signal-processing input, and each of which is either a gain control component or an echo control component; and using the combined signal-processing input to further process the audio signal at the second single-channel audio component; wherein the group of first single-channel audio components and the group of second single-channel audio components is each a group of echo control components or automatic gain control components, or the group of first single-channel audio components is a group of automatic gain control components and the group of second single-channel audio components is a group of echo control components. summing and then combining signal processing inputs from a plurality of far-end channels (350A-N) thereby to provide a combined signal-processing input; receiving at a first single-channel audio component located at a near-end channel of an audio signal transmission path, the combined signal-processing input, the first single-channel audio component being one of a group of first single-channel audio components (1 - M) each located at a different near-end channel (300A-300M) of the signal transmission path, each receiving the combined signal-processing input, and each of which is either a gain control component or an echo control component; processing an audio signal at the first single-channel audio component using the combined signal-processing input to produce a processed audio signal; sending the processed audio signal from the first single-channel audio component to a second single-channel audio component located at the near-end channel, the second single-channel audio component being one of a group of second single-channel audio components each located at a different near-end channel (300A-300M) of the signal transmission path, each receiving the combined signal-processing input, and each of which is either a gain control component or an echo control component; and using the combined signal-processing input to further process the audio signal at the second single-channel audio component; wherein the group of first single-channel audio components and the group of second single-channel audio components is each a group of echo control components or automatic gain control components, or the group of first single-channel audio components is a group of automatic gain control components and the group of second single-channel audio components is a group of echo control components.