perceived loudness of noise vs. sine wave
You need to figure this out by taking into account the Fletch Munson equal loudness curves (or the later ISO revision). However the answer also depends also on the actual loudness of your signal after passing through power amp and speaker, which in turn depends on amp gain and speaker efficiency. This is because the difference between 1kHz and other frequencies varies according to SPL.

Of course, there is also some variation from person to person but for the general case, these curves are about the best guide you have.