If your new DB already has a decent set of strings, I would start using those before changing, to assess your 'unamplified' volume needs. Low tension nylon type strings will generally be quieter than higher tension or steel type strings. Obviously, higher tension strings will require more effort. The volume will also vary significantly depending on technique and how much you 'dig in'. When I first started playing DB, the volume was generally poor, mainly due to lack of technique and stamina. Over the years that has improved and the volume improved as a result.
Good luck.