Methods and systems for mixing digital audio signals are described. In one embodiment, a result buffer is configured to hold resultant mixed digital audio signals that represent multiple combined input signals. A volume ramp function is calculated based, at least in part, on one or more previously-processed result buffers. A current digital audio signal is processed using the volume ramp function to provide a processed audio signal. In one embodiment, the volume ramp function is a linearly varying function and the current digital audio signal is divided by the volume ramp function. At least portions of the processed audio signal are then written into the result buffer. The process constitutes a one-pass method for autogain control for mixing audio signals.