Hertz and cycles per second?

(1) Pure tone at 500, 1000, and 2000 cycles per second for each ear of not more than 30 decibels (dB) on the average, with no individual level greater than 35 dB at those frequencies.

(2) Pure tone level not more than 45 dB at 3000 cycles per second or 55 dB at 4000 cycles per second for each ear.

(3) There's no standard for 6000 cycles per second.

These are the hearing requirements for joining the us. Navy.

http://www.audiofriends.nl/archief/testsignalen/

If I can hear these on the lowest volume on my Iphone without headphones, do you think that it's under or over 30 db on the first and under 45 db on the second?

No way to tell. It depends, for example, how close your iphone is to your ear.