A smoking article filter includes a valved flow restrictor and a cavity downstream of the flow restrictor. The flow restrictor includes an orifice or flow channel for directing smoke into the cavity. The filter is attached to the tobacco rod with tipping paper and includes an air-admissible ventilating zone at a location downstream of the restrictor. The valved restrictor can be used to isolate a sorbent bearing component of the filter from a flavor bearing component.