IPhone has set the SMS ringtone, but it only lasts for one second. What if it doesn't work?

Download the favorite music to the designated folder of the computer, download the AISI Assistant from the computer, connect the data cable, install the AISI Assistant on the mobile phone, select "Trust" in the prompt box popped up in the application interface, and open the AISI Assistant of the computer-select ringtone editing, import the downloaded music, cut, save, import the mobile phone, and set it on the mobile phone. Telephone ringtones and SMS ringtones can be edited. You can edit the ringtone for about 26 seconds and the SMS ringtone for about 24 seconds. After editing the ringtone, you can uninstall the phone without AISI assistant, and the saved ringtone will not be affected. Aisi assistant can also back up photos, text messages, phone numbers and so on on the computer. It's easier than using iTunes.