This is so basic, I oughtta be embarassed to post it, however...

[cwall99]

So I just don't get the way volume controls are marked anymore.

I have no idea how low mine goes, but as I turn it down, my receiver's displays indicates an increasing negative level of dB (e.g. -20dB is louder than -30dB).

I've only had the volume up at 0dB a couple of times because it's soooo flippin' loud (though it sounds great - my wife always yells at me for being so loud - I love the rare occasions when I can play it this loud).

Once, I did go louder than 0dB, just to see what the display did, and, yes, it went to +1dB. So I presume that it continues to increase to some level, but I have no idea how high it goes.

My questions:

- So, if 0dB is that loud, what does the 0dB level represent?
- If dB is short-hand for decibel, and decibels are a unit of volume or loudness, how does my receiver know, without using some sort of active feedback loop that would require a microphone, that the actual number of decibels I've decreased the volume by is an accurate reflection of the negative number of decibels shown in my receiver's display?

Thanks.

 

[cwall99]

Whoops... never mind. It just goes to show you what google and a well-constructed search query can do. I found a great answer, but it was in another forum (that shall remain nameless).... Unless I get asked to post it here.

Sorry for sending anyone off on a wild goose chase.

 

[MDS]

Whoops... never mind. It just goes to show you what google and a well-constructed search query can do. I found a great answer, but it was in another forum (that shall remain nameless).... Unless I get asked to post it here.

Sorry for sending anyone off on a wild goose chase.

Glad you found a suitable answer. I've answered this question no less than one million times since I joined the forum (and was about to do it again).

 

[chris357]

not that i dont know the answer to this very simple question but could you still post the link incase there is anyone else who wants to know

ok, I've been wondering the same thing forever.

 

[Alex2507]

Glad you found a suitable answer. I've answered this question no less than one million times since I joined the forum (and was about to do it again).

I've read that answer about 1/2 a million times and I was going to read it again.

cwall99,

Go ahe3ad and copy and paste the link for us. It's okay ... info is info. They're okay about that. Good info is good info.

 

[Alex2507]

BTW, I wasn't drunk when I posted the above.

 

[mtrycrafts]

... I've answered this question no less than one million times since I joined the forum (and was about to do it again).

With 6+K posts?
Got to have some fun, from time to time

 

[Adam]

With 6+K posts?

I think that it's all of the PMs that are getting to him...

 

[cwall99]

Of course, you gotta figure I lay low for a few days after posting that...

But this is the answer I found: http://forum.ecoustics.com/bbs/messages/34579/498440.html

But, as long as we're talking about simple things, I have another question: as far as I know, heat is a sworn enemy of hi-fi and ht gear. I've always taken care to put my receiver or my amp on top of my stack of components whenever I've set up my rig. Obviously, I want the heat to dissipate as effectively as possible, so I've always felt that the top of the receiver (or amp) should be free to radiate things up and out.

Why, then, when I see stacks of gear in pictures, particularly in pictures in electronics marketing, do you see so many pictures of amps and receivers with stuff stacked on top of them?

Okay, that's more of a rant....

 

[markw]

The same reason new cars always have pretty girls draped all over them.

Why, then, when I see stacks of gear in pictures, particularly in pictures in electronics marketing, do you see so many pictures of amps and receivers with stuff stacked on top of them?

Okay, that's more of a rant....

They look better that way.

Keep the heat generating amp on the top.

 

[MDS]

But this is the answer I found: http://forum.ecoustics.com/bbs/messages/34579/498440.html

Think of "0 dB" on your AV receiver's volume display as a kind of "maximum loudness" setting beyond which you may drive the amplifier into audible distortion or "clipping."

A receiver that does not use the relative volume display but instead uses the absolute display (eg., 0 - 100) also has a point beyond which you may drive the amplifier into audible clipping so that does not explain the purpose of using the relative display. The best point to take away from the article is the volume scale is dB accurate, after you calibrate to a known level and only then can you compare two receivers for relative loudness.

'0 dB' is a convenient reference point. The concept behind '0 VU' in the article explains the idea of a reference - everything else is relative to that reference. In the case of calibrating a HT receiver, the reference is a defined output Sound Pressure Level (SPL).

Here's how it relates to digital audio:

- Digital audio PEAKS at 0 dB, which means the sample value is all 1's. Lower levels are below 0 dB and represented by negative numbers.

- The 'reference' level most people calibrate to is Dolby Reference Level which is 105 dB. So in relation to digital audio, when the sample value on the recording is 0 dB, you want the SPL at your seat to be 105 dB.

- When you calibrate, you use pink noise at a defined level below 0 dB. The receiver test tones are at -30 dB. When you play the test tones and adjust the channel trims (with the master volume set to 0 dB), you want a reading of 75 dB (75 + 30 = 105).

So...with the master volume at zero, you get 75 dB when the input level is -30 dB. When the input level of the digital audio peaks at 0 dB, you get 105 dB. 0 dB audio sample level and 0 dB volume display == the reference level you were looking for.

Now, when the volume display is in the negative numbers, the SPL is less than the reference level. It is convenient because it directly reads how many dB below the reference level is the output SPL. If you calibrated to Dolby Reference Level and are listening with the volume display reading -10 dB, the peaks will now be 95 dB and not 105 dB.

If you are playing something that has an average level greater than the -30 dB test tones you used to do the calibration, it will be MUCH louder at the same numbers on the receiver's volume display.

 

[Phil Taylor]

Sorry .... the topic brought this to mind and I just couldn't resist ....

 

[MDS]

What's funny is that a year or two ago someone else posted this same kind of question and titled the thread 'This one goes to eleven'.