What does 0db on a Recevier Mean?

[poneal]

This question was asked a while back. Well, I was bored the other night and for some odd reason this question popped into my mind. I then emailed HK support and asked them and got this response:

Paul,
Good evening and thank you for your inquiry. You are correct in your
assumption. At the 0dB reference point, the HK receivers are at their
maximum rated power output. In this case, it would be 65W into 2 channels
(55W into 5 channels). We actually provide a little bit of headroom (up to
+10dB), for components that have really low signal outputs (i.e. older
cassette decks, or, turntables).


Thanks again for your e-mail, and please let us know if you have any other
questions.

I hope this helps.


Sincerely,

Mark Tirotta

Internet Support Specialist

*ps: If replying to this e-mail, please include all previous correspondence.


It is the only way that I can keep up with your situation.

Thank you.

-----Original Message-----
Sent: Tue 2/3/2004 6:12 PM
To: Web Support
Cc:
Subject: Harmankardon.com: Questions regarding Harman Kardon North/South
American Products



A message from:
Paul
Model Number: AVR 320

Hi guys/gals, I have a question concerning the 0db reference on the volume
attenuator. Does 0db indicate that the receiver is playing at the rated
output of say 55wpc? If not, what does the 0db indicate? Thanks, Paul.
Tech Note:
216.60.25.6,,Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)

[spacedeckman]

although he did sort of back into it again.

0dB "reference" level would be maximum volume with a fixed 2 volt input (assumption but probably a good one) into a fixed 8 ohm lab grade resistor. Rarely do these things co-incide with reality. Fortunately for you, 65 watts usually isn't part of most people's audio reality either.

Many manufacturers have gone to the THX style readout (as inferred by the h/k help guy) that goes a few dB over reference, referred to as +XdB on the display. Before, 0dB would tend to be full rated output given the parameters above. What does this mean...nothing to most people. But, hey, knowledge is power, and 1 watt is pretty loud.

Later.

[skeptic]

I gave you the right answer the last time this question was asked and I have no idea why I am wasting more time on it but for the benefit of anyone else who didn't see it, here it is. The VU meters are volt meters on the amplifier output even though the markings on the meter face say watts. They have nothing to do with the input voltage level. When the meters read 0db, that means that the amplifier will deliver voltage exactly sufficient to deliver the rated wattage into an 8 ohm load. For example, if the amplifier is rated at 64 watts, it will read 0db when the output is 8 volts. You can satisfy yourself that this is true by disconnecting the speakers and watch the meters swing with no load at all. The amplifier under these conditions is delivering zero watts even though the meters tell you otherwise.

[gonefishin]

dang...I agree with skeptic again


0db on a volume knob is usually making reference to 0db of attenuation. Meaning that the volume is set to maximum output. As you lower the volume...the db numbers should increase.


ex) 99db - lowest volume setting - full attenuation (or possibly mute)
0db - highest volume setting (no attenuation)