The Red-throated Barbet Megalaima mystacophanos is a common bird of the lowland forest. Its calls varies from a single tok to a series of 4 notes. The single note does sound like that uttered by the Gold-whiskered Barbet.
The female has been a source of confusion for some birders. I have seen trip reports which listed the Mountain Barbet as seen in lowland forest such as Poring Hotsprings. Both sexes of the Mountain Barbet resemble the female Red-throated which is differentiated by a small red spot at the base of the rictal bristles on each side. For habitat, the Red-throated is replaced by the Mountain from around 1,000m in most places.