* Vocal strain: If you were pushing your voice too hard or using improper vocal technique while singing the rock song, it's possible that your vocal cords became strained or tired, affecting the quality and range of your voice.
* Lack of practice: If you're not used to singing in a rock style, your voice may not be as conditioned for it. Rock singing often requires different techniques and vocal placements compared to other genres, and it may take time and practice to develop the necessary skills.
* Different vocal techniques: Rock singing often utilizes more belting, distortion, and growling techniques compared to genres that emphasize a light and airy falsetto. If you shifted to these different techniques without proper vocal training, it might have caused a temporary loss of your falsetto.
To get your powerful falsetto back, it's important to ensure that your vocal health is good. If you experienced vocal strain, allow your voice to rest for a few days to recover. Engage in gentle vocal warm-ups and hydration to support vocal health.
Try incorporating vocal exercises that focus on strengthening your falsetto range. For example, practice sliding up and down the scale using a "head voice" technique, ensuring you maintain a relaxed throat and jaw.
You might also benefit from consulting a vocal coach or voice teacher who can assess your technique, identify problem areas, and provide targeted exercises to help you regain your falsetto and develop your rock singing skills.
Remember that every person's voice is unique, and it may take time to develop the abilities you desire. Focus on practicing with healthy vocal techniques and seeking guidance from experienced vocal professionals to safely achieve your vocal goals.