There are studies that sounds from certain sport cars can arouse women so I dont think its weird. Certain sounds just cause some people to get different reactions by effecting different stimuli in the brain. It could also be that maybe you associate those instruments with things that would arouse you? Like do you have a fetish for tribal girls?
That, and for belly dancers or Middle Eastern/North African girls. The gong was prominently used in Ancient Egypt, Turkey and Persia, right?
I believe so, of course also China and other Asian countries used Gongs. So yeah nothing to worry about, you are just a normal healthy horny human being. You should be proud if anything!