Ideas for generating tones at specific dB levels.

Does anybody have any ideas for generating tones at specific dB levels on a per computer/headphone basis and be accurate within +/- 5dB. What I really need is generate a tone a 25dB @4k and one at 40dB @4k from the computer through a pair of headphones and have the tone be accurate within 5dB. I’m not sure on the best way to make sure the tones are really within the range I need them. I’ve tried making a small rig with a calibrated mic inserted between the headphones but I get a lot of background noise (between 45-55dB) showing up when I try to test it, even when they are put in a sound sealed box. Any ideas? I’m still fairly new to the audio world so this I may be missing something simple here.

It would be good to separate the two halves of your task. Generating specific level tones isn’t that hard. The 0dBFS reference tends to carry well all over the world assuming you’re all working from the same audio specifications.

You are after dBSPL. Sound Pressure Level. That’s a very different thing. You are after the CostCo Hearing Test. Very quiet room with large, well padded headphones. I don’t think theirs is absolute, either. I think theirs is relative. Press this button until the tone goes away. Plot the button presses along a frequency graph.

Is that the job? Are you building a hearing tester?