Examination of various issues related to the generation and application of optical frequency combs (OFCs) is an important branch of modern optoelectronics. Some of the proposed OFC generation methods apply acousto-optic (AO) devices. The AO devices are used either as the element devoted to the OFC phase stabilization or they play the role of an optical radiation frequency shifting element in the frequency-shifting loop (FSL) scheme. The results of two experiments related to the application of AO cells in the FSI, scheme are represented in this paper. The first experiment confirms the previously proposed effect of AO mismatch influence on all the OFC characteristics. The second experiment shows the possibility of tunable AO dual comb downconversion with a single AO device. (C) 2022 Optica Publishing Group