Mixtures are described which comprise or consist of 3-(4-methylcyclohex-3-enyl)butyraldehyde (limonenal) and (4aR,5R,7aS,9R)-octahydro-2,2,5,8,8,9a-hexamethyl-4H-4a,9-methanoazuleno(- 5,6-d)-1,3-dioxole (Ambrocenide.RTM.), the weight ratio of limonenal to Ambrocenide.RTM. being in the range from 150:1 to 2500:1.