for general recording I use recforge...i bought pro, you can swap formats, decrease gain It can successfully record vocals during band practice with a loud guitar, so i can find harmonies after if I'm struggling or if a new soong. I highly recommend this app for recording. There are also convert tools and other options
as for lectures, I use lecture notes pro version with lecture note recordings. The recording is not as nice, but good enough and when listening to a play back, i can search, then press a place on my handwritten notes and it will automatically synch the play back to the time when i wrote the notes. I use it with a stylus and it take what i wrote in the window at the bottom and places it on a line in the "paper", it does multi pages, has so many options for tweaking size, font, and way more than I can list here. There is a trial version however the recording add on is purchase only. the lecture notes printed out really nice from phone and tablet or i can share them to google drive, evernote etc. I tried 7 notes and like lecture notes much better with regard to fluency when in a lecture.
and if just a recorder I would go with recforge...HTH!
Kathi
