Want to compress the whole dir with good compression? Try xz compression:
tar -cf - dir1 | xz -9ze -T0 >archive.tar.xz

The latest tar version under #FreeBSD/#macOS/#Linux support the following syntax:
tar -cJf archive.tar.xz dir1

See https://www.cyberciti.biz/faq/compress-the-whole-directory-using-xz-and-tar/ more info.