“Perceived “flat response” is distance related”

YES! Though educated, I could never explain to anyone why this is true. Though I believe the “volume” or size of the room also contributes for more obvious reasons.

I think the distance-related response is due to the directivity of higher frequency sounds. The inverse square law applies at all frequencies, but the apparent focal point of higher-frequencies emanating from a highly directional horn (unidirectional) is further behind the speaker than the apparent focal point of lower frequencies emanating from a large-diameter cone (omnidirectional). This means as you double the distance from the speaker, the amplitude of low frequencies appear be reduced to 1/4, but higher frequencies appear to be reduced to perhaps 1/2 (because the distance from the apparent focal point has not doubled). This makes the sound seem “brighter.”

In working at a plant, I found that a person playing a clock radio for the whole department to hear was an awful awful experience. Thankfully I was an electrician—there to get production going again—and I could leave the area when the machine was repaired.

Years later the boom box entered the shop and it could play much louder and except for their choice of music, it was a really good sound.

I always wondered why two, three and four inch radio speakers had the ability to wear you down so quickly. 

In just a few articles, Dave Rat has earned the term “pre-qualified”.  For me that means, anything he writes is a must read!

There are some interesting comments, but lack sufficeint detail to have a meaningful disscusion.

The comment about comb filtering, is off. Comb filtering only occurs with sources providing the same source signal.

I really respect Dave Rat’s experience and opinions, however some of these topics are non-starters or need qualification.