Bright High End Speakers = Bad Room?

" Do you have a link to the study that mentions this? Thanks "

He describes it in his book, don’t remember whether or not he included a reference. I’ll try to remember look for it this evening.

" what was the explanation? "

I don’t recall offhand what Toole said about it.

I have read that it may have to do with the absorption of high frequencies as sound travels significant distances through the air. At a live performance the distances involved would reduce the amount of high frequency energy reaching the audience, whereas the relatively short path lengths from instrument to microphone and later from speaker to listener do not attenuate the high frequencies significantly.

Duke

Kenjit wrote: "a ruler flat response... is too bright for most folk." 

Floyd Toole, Bruel & Kjaer, and I all agree with Kenjit on that point.

Atdavid wrote: "I do not think overall that most people consider a ruler flat response too bright."

Toole conducted extensive double-blind listening tests and found that most listeners prefer a gently downward-sloping response trend, both for the first-arrival sound and for the early reflections. Most people perceive a "flat" response to be "bright", and a gently-downward-sloping response to be "flat".

But there was one group who consistently preferred a flat response: Recording engineers. To them, speakers are a tool, and in general the more revealing the better. 

Toole did find that, when listening strictly for pleasure, many recording engineers prefer the gently-downward-sloping trend. 

Microphone manufacturer Bruel and Kjaer identified this gently downward-sloping response as being desirable long before Toole confirmed it.

Duke

Kenjit quoted me: "But there was one group who consistently preferred a flat response: Recording engineers. To them, speakers are a tool, and in general the more revealing the better. "

And then he asked: "Do you have a link to the study that mentions this? Thanks" 

I thought it was in the third edition of his book but I just skimmed all of the chapters that seemed promising and couldn’t find it. Nor is the index helpful. If I can find my copy of the first edition I’ll look there. My recollection is that Toole was the source, if/when I come across it I’ll let you know. 

When I have been asked to design custom studio monitors by the acoustician who designed the studio, he has specified "flat on-axis response" as the target. 

Duke

Teo_audio wrote: " I find that the most natural and comfortable to listen to speakers are the ones that employ some subtle version of "The BBC Dip"."

Agreed - a bit of dippage centered somewhere between 3 and 4 kHz does seem to correlate with long-term fatigue-free listening.

One way of seeing the BBC Dip is "inverting the Fletcher-Munson peak", as atdavid so eloquently described it.

But here’s another way of seeing it: The BBC dip is right smack where the bottom end of most tweeters is, where most tweeters have an off-axis pattern flare. The result is a net excess of energy in this region (the off-axis energy perceptually adds to the on-axis energy), and the BBC dip is one way of addressing that.

One day I was curious about whether the BBC dip would be subjectively desirable if there were no off-axis energy flare to compensate for. My designs are constant-directivity over much of the spectrum including that region, so I dialed in some gentle dippage centered between 3 and 4 kHz. What I heard was educational to me.

Yes the speaker became more forgiving, but the harmonic richness was degraded. There was something obviously missing relative to having smooth response through that region. The loss of something quite desirable - timbre and texture and a natural-sounding richness - caught me by surprise.

So while the BBC dip does invert the Fletcher-Munson peak, I have come to believe that its primary raisin d’etre is to compensate for that off-axis energy flare at the bottom end of the tweeter’s range. And if that flare isn’t there, ime the BBC dip would be a step in the wrong direction.

One thing that peak in the Fletcher-Munson curve DOES tell us, in my opinion, is where the stakes are the highest.

Duke