I think this thread shows clearly what has happened in these forums, which were supposed to avoid pseudo science and hearsay - it has gone so "scientific" that everyone is just yelling at each other. A lot of people are just here to bash at something they have never heard
May I suggest not to generalize on the >37000 members based on a few unpleasant interactions / threads? There are a lot of both very knowledgeable and kind people here, and IME a lot of opportunities to learn from them. I personally hope you and others stay and engage / contribute - even if you disagree!
Let me start by saying that I hope you don't see this post as combative - I will just try to clarify a few concepts that I feel might be misunderstood; I hope you may find it useful!
As you say, most people here simply do not really know how to deduct useful information from measurements, as they have grown accustomed to just looking at Klippel "anechoic" measurements, directivity hysteria and completely ridiculous "estimated in-room responses".
I wonder why you put the word
anechoic under quotation marks?
Anechoic stands to mean "without reflections", but doesn't really specify how this is achieved:
- Klippel NFS achieves this by measuring loudspeaker output in the relative nearfield and then applying clever mathematics to remove reflections.
- Another way to do it is to measure the loudspeaker in a calibrated anechoic chamber (which are never truly anechoic in the low bass, BTW - this is why they are calibrated) out of its acoustic nearfield.
- A third way is to use the quasi-anechoic methods (appropriately time-gating the HF measurement and splicing with ground-plane or baffle-step-compensated nearfield LF measurements to get the full-range anechoic response).
All three approaches result in
anechoic measurements (since in all cases the effect of reflections is removed) which, if done correctly, give the same qualitative response and are very comparable. The difference is usually just resolution - NFS having the highest resolution, quasi-anechoic usually the lowest.
If you are interested,
this amazing web resource by
@pierre contains measurements made by various methods, and you can even compare them directly.
Regarding the estimated in-room response / PIR, may I ask why do you think it is 'ridiculous'? I ask because I notice people sometimes mistakenly assume the PIR is supposed to show what we
hear at the listening position. If you read the research it will be clear that PIR is instead meant to represent what would be
measured at the listening position (but only above the room's transition frequency, as it doesn't account for SBIR, room size/treatment and placement). Below the transition frequency room modes and loudspeaker / listener positioning take control and PIR isn't meant to model that - which is also clear from the research.
In my experience doing loudspeaker measurements PIR has proven really successful in predicting how the actual
in-room measured response looks like, see e.g.
here for some examples.
Research also implies that what we hear is definitely not the same as what we measure in-room - we hear more of the loudspeaker direct sound (i.e. its anechoic response) in the mid and high frequencies than what is suggested by the in-room steady-state response.
Related to this, unfortunately there is a common misconception among hobbyist that good sound can be achieved by EQ-ing any loudspeaker's in-room measured response to a specific target (e.g. the Harman target). If you read dr. Toole's book you will see this is never claimed (see also
this post for a reference) - it is actually the other way around - in-room measurements of various good loudspeakers result in a curve resembling what is commonly called the "Harman target". So it is not really a
target for EQ - it is the expected
result when using good loudspeakers.
EQ still has its place in achieving good reproduced sound - it helps to fix certain issues in the bass (mainly reducing peaks / resonances) and it can also be used to improve tonality of loudspeakers that otherwise have even / good directivity.
Blindly EQ-ing towards a tidy-looking full-range in-room response
can definitely make things sound worse, and this is IME actually well understood by many people on this forum!
The penny dropped for me when linked to a suite of measurements of JBL M2 with various carefully placed subwoofers, with the sole purpose of chasing a rulerflat FR measurement at LP in a clearly unlinear room with lots of room mode issues - simply ridiculous
It is so scientific it doesn't even need the real world anymore. Have fun listening to all those perfect FR measurements
I don't know which specific M2 system you are referring to (I must admit I didn't follow all posts), but please note that in the low frequencies humans hear the combination of the room and loudspeaker response, and the in-room steady-state response is indeed instructive to what is heard in that frequency range. Given that the loudspeaker-room system is largely linear and time invariant (LTI), Fourier transform allows us to go from time to the frequency domain (and vice-versa). A resonance in the frequency domain means ringing in the time domain - so addressing the resonance (by room treatment/layout, multiple subwoofers arrays and/or EQ) also addresses the ringing / reduces decay-time at the problematic frequency. I.e. achieving a close to ideal FR in the bass means also no ringing in the time domain. What multiple subwoofers bring to the table is a chance to fill dips in the bass response and make the response more similar across multiple seats - but not necessarily flat response (at least not without EQ).
In short: there may be more than one road to Rome.
Lastly, in case you haven't done so already, I'd really recommend to give a chance to dr. Toole's "
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Room, 3rd edition" book. IMHO it is a really good overview of the field, even if you disagree with some conclusions. There's much more insights, structured clarifications, arguments and references there than one can find in a few forum posts.