Simple technical question

Discussion in 'AV Receivers' started by Dave-Z, Dec 30, 2003.

  1. Dave-Z

    Dave-Z Agent

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    how exactly does the volume level translate into real life numbers? (nagative numbers, etc...) I know this question might sound absurd, but it is something that has been bugging me for a long time.

    Growing up in the days of 1-10(20) volume ranges, I have never truly understood exactly how the current distinctions work.

    My best guess, and what I am working off of, is that when I reach the '0 db level' I am at reference level, or what the makers of said musical(movie) soundtrack determined to be ideal listening level for theatres. (Exactly how do they determine it, and do they differ, or is their an industry standard?)

    Where my question gets a bit deeper, is what exactly is the ratio as one departs from 'zero' level? Is each number simply just 1db above or below this level? (as I think of it currently)

    Another question that comes to mind is the distortion factor. Are receivers generally designed to output to 'zero' or reference level, and above that distortion increases drastically? Makes sense, just trying to confirm my own suspicions.

    Lastly, and I think also very important.... Are all reference levels the same? For example: I'm currently running a denon avr-1700, 70w rated, more like 80w per channel real life... Now, if I upgrade to an NAD receiver that drives each channel at 110w, will the 'volume' still be the same when I have my receiver set at 0db, or reference level, only cleaner?

    I have many other questions along these lines, many just small irritating ones, but I'd love to get them figured out once and for all.

    If you might be able to throw some links my way going into great detail about this subject, I'd be grateful. Even simple explanations would be great. I don't need to be able to write technical manuals on the subject, just have a good understanding. Then again, physics and electronics are interesting to me, so highly detailed info isn't a detractor.

    Thanks for your help!
     
  2. Topher

    Topher Stunt Coordinator

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    Can't go into great detail, but I can throw some generalization your way...

    Some receivers do it differently, like my old receiver goes from 0-50. My new one uses the 0db approach. I don't think 0db on the two different models will yeild the same volume levels, because with the power difference it should take less on the NAD to push to the same volume level as the Denon. It really isn't an exact science (I don't "think") more just a way for companies to use their own terminology. Of course, I could be way off here... anyone else have a better way to explain this? I seem to be running circles around myself.
     
  3. Rick_Brown

    Rick_Brown Second Unit

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    I think you are concentrating on the volume control too much, and not thinking about your whole system.

    For example, different speakers have different efficiency ratings, meaning that some speakers sound louder than others at exactly the same volume setting. The receiver manufacturer has no idea what speakers you will be using so it is impossible to say that any particular setting gives reference levels.

    You must use a sound level meter to find out where your volume control needs to be set at in order to achieve reference levels. One speaker may put out 75db when the volume control is at 0db, and another might need the volume control set to +3db to achieve 75db. It's all relative.
     
  4. Topher

    Topher Stunt Coordinator

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    Thanks, that is what I was trying to say. I just started tripping over myself! [​IMG]
     
  5. Dave-Z

    Dave-Z Agent

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    That certainly helps. Thanks for the replies.

    The speaker efficiency really seems to hit the nail on the head for me. Unless a receiver can auto-detect the load and adjust power across all channels accordingly, there would be no way for there to be any set level in terms of over-all db level output.

    I guess another question would then be: is it safe to assume that receivers in general are pushing their limits above the 0db level if the volume of the system still hasn't reached a satisfactory to the listener? (assuming the listener has normal hearing [​IMG] )

    I don't know if I'll be able to get an across the board satisfactory answer, just trying to create a better knowledge base for my own reference. This seems especially important to me because of the speakers I'm driving, and a currently underpowered receiver.(PSB 4 ohm stratus series(center will be 8 ohm))

    Thanks again for your help.
     
  6. John S

    John S Producer

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    No you can't assume that at all...

    It is arbitrary at the volume control per model of reciever, the output at any given point on the volume knob.

    Remember "Spinal Tap"??? "Our amps go to 11" lol


    As a matter of fact you can totally change the output curve so to speak, by simply changing the potentiometer. (The actual volume controler part the knob is attached to, for any device)
     
  7. Wayne A. Pflughaupt

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    It doesn’t.

    You’re talking about volume (SPL) levels. The receiver’s volume control has no relation to SPL levels.

    You have to remember that the dB is a logarithmic scale is used in many disciplines. Perhaps you’ve seen references to dBv or dBU in the specs of various hi-fi components.

    The numbers on a receiver (or pre-pro) have to do with its output or gain, which is measured in volts. So simply put, the negative numbering refers to “dB before maximum gain.”

    P.S. I don’t have access to my reference materials right now, so perhaps someone can correct me if the particulars here aren’t quite right.
     

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