Hey there tapps2,
Thanks for reaching out to the Apple Support Communities.
If you're able to hear the same issue when playing back a voice memo recording, this may indicate a possible issue with the bottom microphone on your iPhone.
Check out this link for more details: If the microphones on your iPhone aren't working - Apple Support
If people can't hear you on phone or FaceTime calls
1. Open the Voice Memos app.
2. Tap the Record button
, speak at the bottom of your phone, then stop the recording.
3. When you play back the memo, you should hear your voice clearly.
From here the best option would be to have your iPhone inspected further for possible service. You can reach out to Apple Support to discuss service options in your region at this link here: Get Support
Take care!