Sound hiccups sometimes happen and I'm affraid I don't have one 100% solution. It not just sound but also video or in general game speed but most users will only notice sound. Just make sure that only syncrefresh option is mark under Advanced menu. Some people reports that disabling Intel Speed Step or automatic clock ratio may help as well.
Options for choosing frequency is available for many years but to use it You have to enable cheat in mame. After this run game, hit TAB and enter slider controls. It will available from now on. Note that game speed will be changed just like with syncrefresh option.
Edited by haynor666, 23 June 2018 - 01:29 PM.