It was claimed in this thread that fixing the frequency response with EQ would also fix the time behavior (modal decay, ringing). This is NOT generally true. It is only true if the response is minimum phase (or very close to MP). Here's a great article by John Mulcahy (author of REW) explaining the details:
I provided the same answer to you a year ago (http://www.avsforum.com/t/1425262/are-audio-companies-all-involved-in-a-huge-conspiracy/1110#post_22546868) with references and such. Here is some of that back up again:
"For now, it is sufficient to say that low-frequency resonances in rooms behave as minimum-phase phenomena, meaning that if there is a prominent “bump” in the frequency response, it is probable that this will be heard as excessive loudness at that frequency and that for transient sounds, there will be bass “boom” at that frequency. Using equalization to reduce the bump also attenuates the ringing so both problems are solved simultaneously.
At subwoofer frequencies the behavior of room resonances is essentially minimum phase (e.g., Craven and Gerzon, 1992; Genereux, 1992; Rubak and Johansen, 2000), especially for those with amplitude rising above the average spectrum level. This suggests that what we hear can substantially be predicted by steady-state frequency-response measurements if the measurements have adequate frequency resolution to reveal the true nature of the resonances. In minimum-phase systems, the magnitude versus frequency response (henceforth simply “frequency response”) contains enough information to enable the phase response to be computed, and from those two data sets, the transient response can be computed."
Here is the Craven and Gerzon reference:
And Rubak and Lars Johansen reference:
”As pointed out by Craven & Gerzon , room equalizers based on Digital Signal Processors are able to reduce the reverberation time considerably, even if we only use minimum-phase equalizers. Our preliminary test results are in agreement with this important potential for DSP based equalizers. Therefore we have put focus on objective test methods concerning the improvement of the room acoustics using equalizers.”
And from Dirac paper:
”It is clear that even in a good listening room with good speakers a substantial improvement is possible using a careful mixed-phase design. The minimum-phase filter is clearly doing a good job as well; not nearly as good as the mixed-phase design it nevertheless improves the time-domain behavior. In a large well-designed listening room the impulse response would preferably be nearly minimum-phase and that is also the case in this room. Therefore we can cause improvements by just using plain minimum-phase filters. This unfortunately does not carry over to trickier environments such as car cabins”
Your answer to me summarizing in that post, "I will be blunt: there is no way you can build an accurate sound reproduction system in your room without EQ. It is a critical link in the chain. At least the well implemented versions are." was:
Seems like you are having second thoughts on that point
Systems #1 and #2 are the same. #1 however was optimized for one seat while #2 was optimized for multiple. We see that *both* achieve superlative results, outperforming doing no EQ (#4).
As with "RT60 is not good in small rooms" this argument around room response not being minimum phase can be shown to be strictly true but if we understand the science properly and rely on significant knowledge of people who spend decades doing this properly for a living, then we find that the practical answer is not that. Please, please let that guide us in optimizing the sound in our rooms. The constant objections with one liner posts and use of terms without personally explaining what they mean and why, is not helpful. It creates extra noise and chatter with no good results.