Again with having to justify something based on one set of "ideal" circumstances.
Have you listened to Harman speakers? A lot of them sound different from one another. Why is that again?
Do these "other things" include humans and their predisposition for liking all sorts of different stuff, no matter how "illogical" it may be to someone else?
It is crucial to note that several speakers having good measurements with a flattish frequency response does
not at all mean these speakers will sound the same same. As has been discussed many times in this forum (I don't blame you for not seeing all the discussions!), speakers can have a similar looking Spinorama and still sound very different.
Long story short is that it's generally a good idea for most speakers to aim for a flattish frequency response free from resonances, but there's some wiggle room within 'flattish.' Perhaps more importantly, there are many ways directivity can modify the sound of a speaker and its perceived spatial presentation.
Having good measurements is important, but sometimes people take that to mean a homogenization of speakers, which needn't be true. There are many ways to achieve 'good.'
I currently have the KEF LS50 Meta, Focal Chora 806, and JBL-HDI-1600 in my apartment. All three have good, flattish measurements, but all three sound quite different due to their varying directivity. But again, they all sound
good.
I don't think most people here want every speaker to sound exactly the same; we just want some basic standards and more honesty in how products are promoted with regards to their performance per price. Measurements provide much needed transparency.
Personally, I don't care if a manufacturer makes a speaker with a wacky frequency response, so long as it is clear on its intent and doesn't promote the speaker as the pinnacle of neutrality. But that rarely happens.
Unpopular opinion inc:
I kind of agree with the man on the front, that OBSESSING about specs as an end-user is the wrong way to go about it.
It is really unrealistic to look at a FR in isolation and expect the speaker to sound like that in your room.
The room will basically nuke the carefully crafted anechonic FR of any given speaker and if you employ room correction DSP, you will most likely move even further away from the manufacturers target curve.
Naturally, designers should measure. Absolutely. They need to find all the little flaws and correct them as best they can. No argument there.
As an end user, measurements are somewhat helpful in the selection process, especially the ones that go beyond the simple frequency response.
In general, I do prefer a flat response, because then, DSP only has to work against the room and not work against an arbitrary house curve in addition to that.
Edit: clarification that I distinguish between the designers and the end-users.
It really depends on what you mean by "frequency response." Just an on-axis graph? Sure that's not very useful. But a full on spin most definitely tells you what to expect in your room - certainly if you know how to do some basic measurements of your own and know how a speakers response (mostly the low end) will be modified by it.
More importantly, there's evidence to support the idea that while a speaker may sound somewhat different in different rooms, the better speakers are
still preferred in direct comparisons among speakers within a given room.
As such, we musn't give the room
too much credit either. It has a profound effect on the low frequency response, but above 400-500Hz or so, speakers tend to behave as expected. This is both in accordance with research and my own experience, having measured and listened to dozens of speakers in a several locations in a couple of apartments. Yes, some speakers may be slightly better in some rooms than others, but for the most part, the better speakers are just
better.
Per Toole, people "have a remarkable ability to 'listen through' rooms." See Olive etc al 1995, or Toole's book Chapter 7.6.2:
"It appears, therefore, that we can acclimatize to our listening environment to such an extent that we are able to listen through it to appreciate qualities intrinsic to the sound sources themselves. It is as if we can separate the sound of a spectrum that is changing (the sounds from the different loudspeakers) from that which is fixed (the colorations added by the room itself for the specific listener and loudspeaker locations within it). This appears to be related to the spectral compensation effect noted by Watkins (1991, 1999, 2005) and Watkins and Makin (1996)."
It's not so dissimilar from the fact that you can clearly recognize a familiar voice or instrument in a variety of different rooms. Our brains can to a significant degree tell apart the room and the speakers. Which is why it's so crucial to get good anechoic or quasi-anechoic data.