IMPORTANT FACTS ABOUT OUR HEARING AND EQ

[♚Chello]

IMPORTANT FACTS ABOUT OUR HEARING AND EQ

You have probably heard (lol) that our hearing ranges from 20Hz to 20kHz.
Most people, however, have their hearing reduced early on; especially upwards in the frequency range, so that they only hear up to 8kHz from the age of about 37.
(There are people who hear far better, and I still have fantastically good hearing that extends from well below 20Hz to well above 20kHz).

This is not COMPLETELY true, because there is something called plus/minus dB in the frequency range.
What happens is that the sensitivity (dB) decreases with age, so if you increase the number of dB above 8kHz, you will still be able to hear these frequencies even in old age.

It's also more complicated than this:
Our hearing has a negative sensitivity to low frequencies between 20-30Hz as well as high frequencies between 15-20kHz of as much as -20dB.

Therefore, many amplifiers had what is called Loudness, which gives a plus of 20dB in these areas, but works logarithmically.
In short, a logarithm works so that the higher the volume, the lower the Loudness gain in dB.
Our hearing also works logarithmically.

Most speakers; even very expensive ones, also typically have minus 20dB at the extremes of the frequency range.

Then comes an important point:
When you compensate for the lack of sound pressure at the extremes of the frequency range, you must be aware that the louder you play, the more erroneously the compensation will affect the sound, and you will quickly end up with a boost that is far too powerful.

Therefore, I always carry out tests at relatively high sound pressures (80-90dB), to make sure that the boost is not too strong.

My speakers have the rare property that they play from <20Hz to 20kHz> with plus/minus a few dB.

By the way, be aware that power is mostly required in the sub-bass area, which means that if you increase the number of dB with EQ here, this will require much more power from the amplifier, and quickly affect the entire sound image negatively if it has problems delivering the required power.

[⚝Graham UK]

Chello. I fully agree. In my school days the only way for me to check if speakers were in phase was to face them together whilst swapping plus & minus leads.
EDIT. THE CORRECT CONNECTION PRODUCES BASS.

Later years experience I could walk into one of my accounts retail shop and say those speakers playing are not in phase.

At 86 I understand my hearing frequency wise has limitations yet I can still detect good from bad sound.

[♚Chello]

@Graham

Thank you for your experienced words.
I have the same experience with phase - today I hear immediately whether the loudspeakers are in phase or not.

And people must never underestimate the judgment of an experienced listener, even if his hearing is impaired, because sound is so much more than frequencies.

After all, the most important thing takes place in the midrange, and it takes a great deal for the hearing to be so impaired that this is significantly affected.

Incidentally, one of the world's best judges of perspective was deaf in one ear.
Yet he was always right.