Frequency response relative to volume (loudness)?

[Hybrid fourdoor]

Just wondering if the rated frequency response of a driver is relative to a certain volume. By this I mean if a driver is in a smaller volume of air can it have a broader freq response, such as headphones. Headphones have a very small diahgrams, with little excursion, yet are rate as 40-18K (or whatever), but at a very low volume, and it in a very small space. So my question is could a driver (say a tweeter which might be rated as 3k-20k) have a broader response (say 200-20K) if it were used a small conceiled area?

[454Casull]

Sure. The smaller the environment, the higher up in the response "room gain" (loosely speaking) occurs - that is, where the lower frequencies are increasing in volume by a certain level per octave downard.

[sreten]

Basically for tweeters no.

Excursion requirements come in with a vengeance at a phenomenal
rate once you start dropping the lower cut-off frequency point.

sreten.

[Hybrid fourdoor]

Ok so a 4" woofer in a very small displacement at a low volume, would have an amazing frequency response then? Say if you measured it inside a tupperware container?

How are headphone diaghrams different than a tweeter? They <headphone> don't have much excursion either do they?

[Svante]

Originally posted by sreten
Basically for tweeters no.

Excursion requirements come in with a vengeance at a phenomenal
rate once you start dropping the lower cut-off frequency point.

sreten.

I think that playing the tweeter into a closed cavity and listening into that cavity would add a -12dB/octave slope, that would compensate for the 12dB/oct slope of the tweeter under its fs. There would be no need to increase the dome amplitude. The trouble would be to make the knees of the responses to coincide.

[Mudge]

Headphone drivers are mounted in the ultimate close coupled horns, the human ear canal. You're also talking about the SPL at 0.05M unless you have a huge head. You can try the maths if you want and you can see what the excursion requirements are.