Your iPhone's voice memo app records audio in compressed format by default, saving storage space on your iPhone but reducing recording quality. You can switch to a lossless mode for maximum credibility.
By default, your iPhone plays voice notes in compressed format. But if it does not cut late mustard for you, there is an alternative to switching to a lossless recording instead. It is not clear which file format your iPhone uses here, but it suffices to say that it will take up more space than a compressed AAC file. Think about it, but considering most of the voice memos is probably quite short, we don't think it will have a big impact.
How to choose Lossless Recordings
As always with iOS, the setting we see for is in the setup app. Open it and press "Voice Memo" to get started.
Then touch "Sound Quality" at the bottom of the screen.
The next screen has two options. Press "Lossless" for the best sound quality from your recordings. If the room is your biggest concern, but we suggest you stick with "Compressed" and leave everything as it is.