The problem we have regarding measurements is NOT our ability to measure. The problem is knowing WHAT to measure. And there is rightly considerable debate on this matter.
- We use sine waves because they are simple to use and can be easily calibrated. Music is clearly not a sine wave.
- We test into purely resistive loads because they allow simple comparison. Speakers are not purely resistive.
- We test anechoically because room reflections are unpredictable. We never listen anechoically.
We could produce testing that is more representative of real-world conditions but the debate has been over how to do so in a controlled and repeatable fashion so it can be used as a basis for comparison. For instance, we could test amps into a reactive load but which real-world speaker should that load represent? We could add reflections into a speaker test but whose room should that represent? Any "real world" test scenario is going to be a far cry from actual real world usage. We are still left pondering the relationship between the test and what we experience.
I don't think the testing methodology relevance problem will ever sufficiently satisfy the majority. Nevertheless, I do think there needs to be more transient test signals and more reactive load testing. In my years of selling test equipment, I regularly encountered companies that had devised their own tests to test their products. They felt their tests gave them unique insight and were a competitive advantage. They were reluctant to share their methodologies with any standards efforts.
I have sat on several audio standards working groups where new tests were being pondered. These efforts would frequently get off into pie-in-the-sky methodologies. My contribution was often a commentary of the practicality of the suggested test methodologies using the test equipment that currently existed in the marketplace. Some ideas were scuttled because there was no practical means for the average company to implement the test being considered. However, ideas that we may not have been practical 5 years ago may be practical today. The situation is never static.