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 Subject: Home Theatre equipment Category: Science > Technology Asked by: rbeatse-ga List Price: \$5.00 Posted: 21 Mar 2004 10:26 PST Expires: 20 Apr 2004 11:26 PDT Question ID: 318935
 ```On my home theatre receiver, when the down volume button is pushed the numbers on the display (shown in Db, decibles)go up and when the up volume button is pushed the opposite happens. It is not just this brand (kenwood), I have seen this in all receivers that show the volume listed in Db. If the display just shows a number (no Db designation) then it works like you would expect. Why does it work this way?```
 ```Hi rbeatse! This is quite an interesting question! First, I assure you that there is a purpose behind displaying the volume this way. In fact, it is a more precise way to describe the volume of sound than the "conventional" method of displaying louder sound as a higher number. A good explanation (and why it is better than the "conventional" way) is as follows: "Why does the volume knob have 0 decibels at the top? Well, let's see what happens if we put 0 decibels at the bottom, and count up from there. The only thing 0 decibels could mean is "no sound": when the volume is turned all the way down, no sound comes out. If you went up 10 decibels, or 1 bel, then you'd expect 10 times as much sound to come out. Unfortunately, 10 times 0 is 0, so you'd still get no sound. Hopefully you didn't spend all that money on your fancy stereo just so you could get no sound out of it. Let's try it the other way, with 0 at the top. The only thing 0 could mean at the top of the dial is "maximum volume," where your amplifier is amplifying as much as it possibly can. If you went down 10 decibels, or 1 bel, then you'd get one tenth of your maximum volume. If you went down another 10 dB, you'd get one hundredth of your maximum volume. Another 10 dB down, and you'd have a thousandth of your maximum volume. This is sounding much more useful. If you went all the way down to 100 dB below maximum volume, then no matter how loud your fancy amplifier is, one ten billionth of its maximum volume would be sufficiently close to "no sound" that you wouldn't notice it. " [ http://mozart.fiction.org/2001-05-06.html ] So, when the stereo is putting out the maximum volume that it can produce, the display reads zero dB, and you need to think of the negative values on the display as relative to that absolute maximum value. The need for this system, if you want to be precise, stems from the fact that you CAN precisely describe the maximum volume (simply the wattage/power capacity of the unit) and delineate this as a value, but because the relative unit of bels or decibels are used, you cannot accurately describe a volume that is a magnitude greater relative to a very quiet volume. This makes more sense if you have a good understanding of the system used to describe relative vs. absolute sound volumes, the decibel scale. An explanation of this system can be found at: [ http://www.tpub.com/content/neets/14188/css/14188_50.htm ] Other stereo systems, those that do not display the figure in decibels nor as negative numbers, usually have a number range that goes from zero (quietest) to some arbitrary number generally between twenty and one hundred. These numbers are completely arbitrary, and are just used as a relative indicator of volume, but have the problems that are accounted for by the decibel display system. I trust this information has answered your question completely. If there is a need for clarification, please request one before rating this answer. Thanks for bringing your question to Google Answers! Regards, Andrewxmp search terms used: stereo "volume control" display decibels up down [ ://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=stereo+%22volume+control%22+display+decibels+up+down ]```
 rbeatse-ga rated this answer: ```A very complete and well written answer. The answer was given exceptionally quick. As a first time user of Google Answers, I am very impressed! The researcher's inclusion of the source links allowed an increased understanding while the basic answer was still highly sufficient.```