Expert: Cleggsan - 5/21/2009

Question
If our ear are less senstive to bass why is it I can hear them louder outside of my room or outside of my house for that matter more than the mid or high frenceies.

Answer
Where did you learn this?  It is not a proper conclusion strictly speaking.  According to the Fletcher Munson audible frequency versus loudness studies it is true that at low frequencies the threshold of hearing is lower at low frequencies.  But, not at loud levels.  So, when we hear loud sounds that are over, say 75 or 80 db the bass is very strong.  Further, the music now days is loaded with lots of roaring bass and the audio systems, especially those in crank up cars, is over exaggerated to the end that the bass seems overpowering to nearby listeners.

Further to this mystery is that low frequencies, those under 100 Hz, are very non directional;  that is to say that a speaker system pointed away from you will fire its upper frequencies in the direction opposite the listener and will not be heard so well while the bass is non-directional and will sound almost the same level any which way the speaker is facing.  To prove the point, when you hear a car go by that has big subwoofers in the trunk you can hear the subs pumping away like crazy half way down the bock but you don't here the high frequency sounds that the passengers are hearing inside the car.

And so on.  Enough for you?  Let me know if you have further thoughts.

C

PS:  Harvey Fletcher, the father of stereo sound and the author of the first tests made on threshold of hearing while he was a researcher at Bell Labs is (was, he is far gone now) a personal friend of mine . I worked with him after he retired from Bell Labs in his acoustics laboratory at the university.  I helped him design a 5 channel audio system that was used on a large mountain to provide high fidelity sound to crowds of 20,000 people who gathered for outdoor pageantry.