Have a resistor on for 400 ms then change path to a lower resistance
If this 'resistor' is in a feedback pathway, the ADG1611 should do the trick. With leakage in the nA range and cross capacitance between channels at ~100pF, it should affect your audio signal very little. It also has very little charge injection when switching (which would reduce 'pop' noises).
It does vary resistance (because it contains a PMOS and NMOS transistor in parallel that are matched), but it's less than 1Ω in most cases.

Source: https://www.analog.com/media/en/technical-documentation/data-sheets/ADG1611_1612_1613.pdf
Or an NMOS transistor could work also



simulate this circuit &ndash; Schematic created using CircuitLab