negative dB?

Discussion in 'Playback Devices' started by PeterK, Jul 18, 2004.

  1. PeterK

    PeterK Supporting Actor

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    why on my dvdplayer/receiver are the decibels negative I think the lowest volume is -88 and it goes up to 0? It hurts the ears if I go higher than -10 so I rarely do.

    Thanks
     
  2. John Kotches

    John Kotches Cinematographer

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    dB (Decibel) is in and of itself a unitless measure which is a convenient way of referring to logarithmic relationships.

    In the case of your receiver, the values are relative to the maximum output (0dB) available. A - value just indicates that the output is less by the ration defined. FYI, a drop of 10dB is 1/10th the power of the full output.

    Cheers,
     
  3. Andrew Pratt

    Andrew Pratt Producer

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    To put it another way think of your volume control as a the way to reduce full volume only (ie not boost it). If you connect your CD player directly to the power amplifers it would be playing at full blast as there wouldn't be anthing to reduce the voltage. This wide open condition would mean that its playing at its maximum volume and that all you can do from that point forward is reduce the volume by turning the volume knob. So since full volume means there's nothing being applied to reduce the volume we say that's 0 dB...everything other value will imply that you've reduced the systems potential so you see a negative dB value to show you how much you're reducing it from its wide open state.
     
  4. Wayne A. Pflughaupt

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    Peter,

    John and Andrew are correct. It’s more accurate to think of the volume knob as an attenuator.

    Regards,
    Wayne A. Pflughaupt
     

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