Within my site I many times stressed the importance of upper bass region for sound reproduction. I always said that with the improperly sounding 200Hz -400Hz any further "fidelity" of Sound becomes imposable. Ironically the 200Hz-400Hz is the most compromised region in audio. The film and electrostats driver are run out of steam at 200Hz -400Hz and have no tension and dynamics in there. The standard 2”-4” compression drivers are already dead at those frequencies. Pretty much only direct radiators, directly or horn loaded, can handle the 200Hz -400Hz more or less appropriately.

Experimenting with prominence of 200Hz -400Hz I found that this is the most important octave and there is no other octaves in auditable range equally important. Interesting that if you audition any single octave with high order band-pass filter then the 200Hz -400Hz would give you the most information about the recorded music. Furthermore, with certain training it is possible to extrapolate the "whole music" out of that single octave....

The explanation why our senses are so developed at 200Hz -400Hz and why the evolution of musical development made the most fundamentals of our musical instruments to live at upperbass is not complicated. The human fetus begins to register and recognize sounds after 16 weeks and at 25 weeks it’s hearing is well developed. Being submerged into womb’ liquids and sitting behind many other mothers’ intestines the fetus not able to hear any other noises then the harmonics of the mother voice. However, the bowels of the mother’s body and the amniotic fluids act as a very high order band-pass filter that killes any other frequencies beside the upper bass. So, we pretty much before out birth are tuned to “get” just  arond 200Hz -400Hz and those frequencies are something the "defines" sound for us. Surly if we were rats or dolphins then our physiology were different and our “primary frequencies” would be different.

Meanwhile, learn to listen the “primary frequencies”. Learn to recognize them in sound and learn to discard any audio that does the 200Hz -400Hz improperly

Rgs,
Romy the Cat

clarkjohnsen wrote:

Middle C is 256 Hz, high C is twice that -- hence we have what musicians call "the melody range", roughly 200-500 Hz. That ain't bass!

BTW, I did not know that musicians call it "the melody range" – butt this perfectly makes sense….

Rgs,
Romy the Cat

dazzdax wrote:

Romy, are you sure the unborn fetus is exposed to sounds in the 200-400 Hz range? I think it's more of 30-200 Hz (conducted sounds of mother's heartbeat and footsteps). I think babies are also sensitive to these range of sound: they sometimes fall into sleep when hearing repetitive sounds in this range. There is a Japanese story about a baby who fell in sleep after hearing the sound of the O-daiko, or the big Japanese drum.