From: SFPhysics@aol.com
Date: Thu Jun 22 2000 - 01:41:52 PDT
From: SFPhysics@aol.com Message-ID: <15.57d2f77.26832b50@aol.com> Date: Thu, 22 Jun 2000 04:41:52 EDT Subject: Re: Loudness Button Function
> Hi pinholers, I hope you've been enjoying your vacations. My roommate and I
were discussing the use of the loudness button on his amplifier. I remember
being taught something about it creating false tones to imply loudness.
> Does anyone know exactly how the loudness button works?
> -David Barrios
> Galileo Academy
>>
Greetings David:
One of the oddities of the human ear is that at low volume levels the bass
frequency end of our hearing seems to drop off faster than the mid and high
end frequencies. The "loudness" button changes the frequency response curve
of the amplifier to boost the bass and lower mid frequencies so the music
won't sound strange to our ears when the volume control is way down. This
came from an era when soft music played low was good for background ambiance.
We ancients called it "romantic."
As to how it works is simple, on the older amplifiers with analog volume
controls a tap was placed on the potentiometer that tied into an RC
(resistor-capacitor) "T" filter that let more bass pass. When the volume
potentiometer was set lower than the filter tap and the switch for the filter
was turned on, the lower frequencies passed into the next stage of the
amplifier with a boost.
Digital amplifiers use Boolean algorithms to boost the bass when the volume
is low on them and the loudness is activated. Actually the logic circuits in
digital audio are very impressive.
Today with most music played loud the loudness function is rarely used or
heard. Try some nice soft music with the volume turned way down and activate
the switch. You should hear the bass boost cut in.
Regards to all Pinholers...........
Al Sefl
Who is looking for a science job in SF that hasn't already been filled by
someone with an out-of-state temporary emergency credential................
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