test tones on a perfect setup

[uncoolgray]

What am I supposed to be hearing when I listen to test tones on a perfect monitor+room setup?
Should each frequency have the same subjective loudness? ie should 25Hz sound as loud as 85Hz
Or should there be a smooth increase in subjective loudness as frequency increases?
so that 25Hz is not as subjectively loud as 85Hz

My test tones are pure sine waves from G# -1 25.956 Hz to E1 82.407 Hz, going up in semitones, all at 0dBFS.
(to position a subwoofer)
Why all the decimals, I know, but at least I can get that right.

I listen to the tones on Sony MDR 7506 headphones. There is a gradual crescendo. Subjective volume starts quiet at 25Hz and gets pretty loud by 85Hz (all tones are 0dBFS). Is this what would happen under ideal monitoring conditions, should I aim for this with my monitor/room setup?

[Jerry Tubb]

Refer to the Equal Loudness Curves at 80-90dB:

http://hyperphysics.phy-astr.gsu.edu...nd/eqloud.html

and the frequency response of your monitoring system.

They're far from flat or perfect.

JT

[Ethan Winer]

Originally Posted by uncoolgray

What am I supposed to be hearing when I listen to test tones on a perfect monitor+room setup? Should each frequency have the same subjective loudness?

The whole point of test tones for checking loudspeakers in a room is to measure the response, not listen to them. Most rooms have numerous peaks and nulls of 30 dB or even more, and you'll never assess that accurately by ear. You'll be able to hear that the response is off, but not by how much or where.

Also, test tones and frequency response are only half the story. Time-based problems like early reflections, flutter echo, and ringing are just as important, and test tones will never show that. Below is a waterfall graph that shows both the response and ringing for a typical untreated room. In this type of graph the "mountains" come forward over time.

--Ethan