What is the song that goes Wah ah oh oh oh oh in a high voice?

The song you're referring to is likely "Wake Me Up" by Avicii. The catchy "wah ah oh oh oh oh" is part of the chorus, which is sung in a high-pitched voice. Released in 2013, it blends elements of folk and electronic dance music, making it a popular anthem. If this isn't the song you meant, let me know for further clarification!