I wonder how this gels with the science that the same speakers are preferred regardless of room. It would seem to be somewhat at odds. If different curves are preferred in different rooms, then wouldn't that also mean that different speakers(that produce different curves) also be preferred?
I think there is also the smoothness of the curve that matters. It may be that speakers are preferred in different rooms are also ones that have superior smoothness than what is being compared.
Greg Timbers used to have a quote where he tried to capture the difference between the JBL and Revel house sound.
The 4367 is a good system for those who like the large Monitor format. It measures well, sounds detailed and musical but is lean in the bottom octave as are all of the post 1985 or so "Japan" product. The speed and excess excursion capacity of these systems makes them good candidates for EQ, or for the proper use of a subwoofer, say below 40 Hz. They do have a "live music" sound that is most difficult to achieve purely with direct radiators. If you are looking for an Audiophile loudspeaker with 3-dimensional imaging, a warm mellow midrange and no dynamics at all, look elsewhere. Without using the words Distilled Water you might look at another Harman brand if you are seeking elegant, luscious elevator music.
The live sound component I don’t have a quote for but has been summarized as follows:
Pretend you are walking through a pre-Covid shopping mall around Christmas Time. It’s loud, there is a lot of random background noise. In the distance, you hear music playing.
The SNR is poor and imaging is non existent.
BUT, you know instantly whether that music is a live band or a recording.
Greg Timbers attributed this to “dynamics.” The ability to reproduce these contrasts was a priority of his speaker designs. Develop speakers that sound more like live music, even at the expense of holographic imaging or smoothness was the classic JBL sound.
Greg Timbers goes further to explain:
As I mentioned, I believe that solid Dynamic behavior is most important to get lifelike sound. Dynamics require high efficiency since transducers are pitiful in energy conversion. I also believe that sound staging is extremely important. I think natural midrange and bass presentation precedes the treble range. Of course all things have to be balanced!
And
Parts are everything. The solidity and materials used in the enclosure, transducers are supremely important. So is the quality of the electronic components and circuit boards used in the crossover networks. That is one of the areas that measurements don't adequately represent. It is easy to hear the difference between two capacitors of different construction and materials, for example.
It is worth noting that Greg Timbers uses electronic crossovers for his personal systems. But this is where JBL invested a lot in custom transducers.
Finally,
Speakers have generally become smoother, more 3-dimensional and much smaller. This means that they are less dynamic on the whole and rather toy like compared to good stuff from the 60s and 70s. Unlike electronics, miniaturization is not a good thing with loudspeakers. There is no substitute for size and horsepower. Nothing much has changed with the laws of physics in the last 100 years so what it takes to make dynamic life-like sound is unchanged. There have been some advances in magnet materials and a bunch of progress in adhesives but not much else. The cost of a 70s system in today's economy would be considered unaffordable and the system would be deemed unnecessarily huge. The large highly efficient systems of old came at a time when 15 – 30 watts of power was the norm. Today's stuff would choke on those amplifiers. Now that power is cheap, size and efficiency has been thrown out the window because you can always apply more power. Unfortunately, more power does not make up for lack of efficiency. Today's speakers range between 0.1% to maybe 0.5% in efficiency. (On a good day) 60s and 70s stuff was more like 1% to 10%. With most of the losses gong to heat, turning up the power on a small system with small voice coils and poor heat management is definitely not equivalent to a large high efficient speaker.
It is true that the response of many of the old systems was a bit ragged and generally less attention was put in the crossover networks because simplicity generally means higher through-put. However, the big Altec's, JBL's, Klipsch's and Tannoys of the day would still fair well today with a little modernization of the enclosures and crossovers.
Today's multi-channel home theater setups let a bunch of small toy loudspeakers and a sub or two sound pretty big and impressive to the average Joe. I think speakers have mostly become a commodity and small size and price are what counts the most now. The few high-end brands left are struggling for market share in this age of ear buds.
So to summarize, JBLs didn’t care about directivity errors if it improves efficiency. That’s why they have a lot of big 15” woofer designs with vanishingly low distortion.
Importantly, Greg Timbers was let go from JBL and at least in the US, Revel speakers outsell JBL Synthesis speakers wildly. The market did NOT support the classic JBL sound. However market preferences and individual preferences can be different and both be scientifically based.
