As others have noted, all gear sounds better when played louder, within their performance envelope. Many will scorn their use, but if your Marantz has a loudness button, give it a try. If you're satisfied with the result, then don't worry for now. You can revisit this choice when your children are older.
Also, if you have heard gear played at your desired volume range and with the sound you seek, please let us know the details.
My personal take - if I could only play my stereo quietly, I'd probably own Magneplanars. If you've only heard boxes, you should definitely check out Maggies or electrostats.