will i lose my photos, voice recordings, videos and notes if i reset my samsung galaxy s1
Yes. Surely you will lost your personal data, contacts and everything. To avoid this, you should Backup your files and everything to your SD Card. You can Restore it again to your mobile. 

This following site will help you how to take backup and reset your mobile and then restore it back. 

http://www.wikihow.com/Reset-a-Galaxy-S

Thats all.. :-)