Please explain a receiver's volume level indicator

Discussion in 'Archived Threads 2001-2004' started by Susana Anderton, Nov 20, 2001.

  1. Susana Anderton

    Joined:
    Jul 29, 2001
    Messages:
    49
    Likes Received:
    0
    Trophy Points:
    0
    Can someone please explain to me why my receiver indicates the volume level with the negative/positive numbers? How does this work?

    Thanks
     
  2. Brian Corr

    Brian Corr Supporting Actor

    Joined:
    May 10, 1999
    Messages:
    535
    Likes Received:
    0
    Trophy Points:
    0
    I think the idea is to calibrate dobly reference level (which is 105db) to the "00" setting. It doesn't quite work that way on all receivers but if you do calibrate that way and then are listening to a movie with the dial set at -15, then you would be listening at -15 db from reference or 105-15 = 90db. It's a way for you to reference the volume level to an actual decibel level.

    If you have an SPL meter and Video Essentials, then you would play the test tones from video essentials with the volume at "00". Then use the receiver's individual channel level adjustments to set them at 75 db using the SPL. Keep in mind that the tones on video essentials are recorded 30 db under dolby reference, hence the 75 db setting.
     
  3. Andrew Pratt

    Andrew Pratt Producer

    Joined:
    Dec 8, 1998
    Messages:
    3,806
    Likes Received:
    0
    Trophy Points:
    0
    Brian is correct. Think of it this way. An amplifier is simply a device that amplifies the signal its sent. The amp always runs full throttle so we need someway of turning down the signal that it is sent otherwise we'd blow our ears and speakers[​IMG] This is were the pre amp comes in. Now the reason the numbers are in negative is that your source (CD player etc) sends a signal thats also full throttle so if you plugged the outputs from your CD player into the amp they would both be using a full strength signal which obviously would be very loud. So the pre amp starts out receiving a full strenght signal that as you turn the volume knob it slowly starts scalling back the volume that it passes on to the amps. Since it starts out at full strengh it makes sense to have the numbers decrease as volume decreases and since we use 0 as the reference volume going down from zero gives us a negative value.
    Make sense?
     
  4. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
     
  5. John Kotches

    John Kotches Cinematographer

    Joined:
    Mar 14, 2000
    Messages:
    2,635
    Likes Received:
    0
    Trophy Points:
    0
    Wayne,
    Actually the statement that 0.0dB corresponds to dolby reference level is correct.
    Calibration tones are provided at a typical -30dB to reference from most receivers/processors so 75dB on the meters is required.
    Whether the receiver or processor/amp combo can deliver that during playback of materials is another issue altogether.
    Regardless that is exactly what 0.0dB means -- if your setup has the power, and the speakers can deliver the SPLs, you will get 105dB from regular speakers, and 115dB from the subwoofer at 0.0dB on the dial. If not, you'll get distortion big time [​IMG]
    Regards,
     
  6. John Kotches

    John Kotches Cinematographer

    Joined:
    Mar 14, 2000
    Messages:
    2,635
    Likes Received:
    0
    Trophy Points:
    0
    To further clarify my earlier post, you have trim controls to get as close to 75dB on all speakers as you can uniformly produce.

    So 0.0dB is a preset value.

    If you have to trim way + to hit 75dB, then you likely will run out of gain on playback before you hit 0.0dB.

    The nice thing is, when calibrated to reference you can goto -10.0dB and realize that you'll peak at 95dB and 105dB respectively for mains and subwoofer.

    Regards,
     
  7. John Morris

    John Morris Guest

    And, keep in mind that the internal calibration tones of the pre/pro or receiver usually don't match up to the Avia tones when played back through your DVD player. So, in the end, those -10 etc... numbers may be irrelevant except to you who know that -13 = reference level when you play back DVDs.
     
  8. jeff peterson

    jeff peterson Supporting Actor

    Joined:
    Nov 29, 1998
    Messages:
    675
    Likes Received:
    0
    Trophy Points:
    0
    Going back to Andrew's post for a minute, my Yammy 2092's 0 point on the volume control is at the END of the control's travel; ie, all the way ON. This makes sense in relation to Andrew's explanation of the volume control numbering scheme but doesn't in relation to Dolby Digital reference level.

    Do the newer Yamaha receivers follow the reference level numbering or the Andrew method?
     
  9. Matty B

    Matty B Stunt Coordinator

    Joined:
    Aug 27, 2001
    Messages:
    227
    Likes Received:
    0
    Trophy Points:
    0
    Does ANYONE listen at zero? I've listened at 25 when I REALLY wanted to get crazy and it was loud as SHIT. I'm 23 and have SUPER sensitive hearing too, I can't imagine other people being comfortable with anything louder. I sit around...8 feet from my fronts and 3 feet from my rears BTW.
     
  10. Bill Kane

    Bill Kane Screenwriter

    Joined:
    Feb 5, 2001
    Messages:
    1,359
    Likes Received:
    0
    Trophy Points:
    0
    Welcome to the Forum, Susana.

    So, ask a simple question and look what you get. What else from guy-geeks. (hey, it's our arcane hobby).

    Anyway, back in the days of tube and solid state stereo amplifiers, we were used to the dial-type volume knob, turning it up from 1 to 12 like a gas knob on the stove, and watch out for going too far!

    Today, new Dolby decoding 5.1 digital amplifiers come with a decibel-rated style volume control, or output level if you will. It's still a sound "loudness" control, just calibrated in a negative decibel scale. Like the previous posters say, 00dB is MAXIMUM strength. Likely, if you turn it to 00dB with no actual source, you'll hear hiss from the speakers -- not good.

    Lots of receivers, well, Yamaha anyway, don't even start to get loud until the volume knob is turned 3/4s the way, say to -45 dB. That's the way they come.

    Your main and surround speakers are adjusted two ways at once: by the volume control on the amp itself, and by the receiver-remote's speaker level/menu settings. It's a trade off where you end up at Dolby Reference.

    It's OK to adjust the remote's settings into the -5 to +5 dB range for the mains using a Radio Shack analog Sound Pressure Level meter or SPL, and then match the surrounds, all the while adjusting the amp volume until you see 75db or optional 85dB on the SPL meter.

    For me 75db "reference" came out at -27dB on my amp dial. I write this on a post-it to remember this number is my DVD 5.1 theater-level MAXIMUM. Most people at home actually listen 5 to 15 db UNDER or below your movie sound track reference. You get accustomed to this numbering system in time.

    I submit this in good faith sans condescension, your honor.
     
  11. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    Some confusion arises because the scale which receivers use for marking their master volume controls can differ. Some use a simple rising number as the volume goes up. A rise of 1 might not even signify a 1 dB increase in gain. More advanced receivers and pre-pros tend to have a master volume which starts at the soft end with negative dB numbers and go up to positive dB at the loud end. Those receivers are probably the easiest to conceptualize.

    Basically the manufacturer has provide a convenient means by which you can standardize you communicate how loud or soft sound is being created in your system. This standardization is needed if you wish to convey the exact loudness so someone else can replicate your experience or more importantly in home theater to replicate the sound of another system - namely that of the mixing studio.

    Once properly calibrated, the reading on the master volume does account for room size, amplifier gains, source level, speaker efficiency and acoustics. It does so because the calibration you perform recreates the target SPL level of signals which were recorded to reach a specific SPL reading. You play back signals which are known to create 75 dB SPL (or 85 dB SPL if you are using AVIA) on a system which is at "reference" state. While doing so, you have the master volume of your system set at 0 dB and then adjust the channel levels so the measured SPL on your system is also 75 dB SPL (or 85 dB SPL if using AVIA). Once that is done for all speaker channels, your master volume setting reads out how far above or below your system is relative to reference. The standardization means that if you say you have volume set 10 dB below reference, other people know how loud that actually is. Without the calibration step, the master volume number is meaningless.

    Some receivers, automatically set master volume to 0 when you adjust channel levels. Others require you to set it manually. On receivers without a 0 dB point on the scale, you may have to mentally take note of what number on the scale corresponds to reference (say 70 on the dial). Then when you tell anyone else your volume setting you'd have to do the math to make it sensible to someone else.

    Note that reference level means the same measured SPL get reproduced at your listening position, but does not mean the same energy is being output by a system. It takes more energy to fill a stadium at reference level than your living room, but both would be at the same measured SPL level (at your listening position) if both are set at reference.

    Quite a few prefer to listen with the volume set below reference. 10 dB below reference is common, but some prefer even lower. Interestingly, there is a 6 dB difference between preferred sound levels for males and females leading to some compromises for couples over the volume level. Ever notice that men usually turn the volume up while women tend to turn the volume down? That's one reason why.

    One other tidbit to remember is that the perceived tonality of sound changes as volume decreases. At lower levels, bass and treble tends to sound softer. That's why many of us who prefer a lower SPL level also boost the bass level to compensate for the naturally lower bass response of hearing at a lower volume.
     
  12. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
     
  13. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    THX has changed the game, Wayne.
     
  14. Holadem

    Holadem Lead Actor

    Joined:
    Nov 4, 2000
    Messages:
    8,967
    Likes Received:
    0
    Trophy Points:
    0
    I agree with Wayne: I don't think 00dB on receivers has anything to do with Dolby Reference Levels. I doubt you would get the same SPL from different receivers at 00dB (same speakers of course).

    --

    Holadem
     
  15. Wayne A. Pflughaupt

    Joined:
    Aug 5, 1999
    Messages:
    6,123
    Likes Received:
    40
    Trophy Points:
    6,610
    Location:
    Katy, TX
    Real Name:
    Wayne
    "THX has changed the game, Wayne."

    But most receivers aren’t THX.
     
  16. Guy Kuo

    Guy Kuo Supporting Actor

    Joined:
    Mar 6, 1999
    Messages:
    581
    Likes Received:
    0
    Trophy Points:
    0
    Okay. Let's restrict it to 0 dB on the master volume indicates the system is producing reference level SPL at the listening position provided that....

    The system has been correctly calibrated to create reference level with the master volume at 0 dB.

    The system is appropriately sized and powered for the playback venue.

    Without calibration, the 0 dB indication on the master volume will yield a completely unpredictable SPL level at the listening position. That is why calibration is useful. It standardizes the SPL level for a given master volume setting. It does NOT standardize the amount of wattage delivered to the speakers - just the final SPL level at the listening position.

    I completely agree that not all receivers are designed to match the THX model. So, on non-THX style receivers, the readings on the master volume dial don't necessarily mean the same thing as they do on a calibrated THX system. It's completly possible for the scale to not be in dB increments and the range to begin and end at any arbitrary numbers.

    Given that I think we can all agree that the differing methods by which master volume controls can be labeled could lead to considerable confusion and hence this thread, which by the way seems to begin by asking about a receiver with a master volume which is designed to match THX specs.
     
  17. Ken Chan

    Ken Chan Producer

    Joined:
    Apr 11, 1999
    Messages:
    3,301
    Likes Received:
    0
    Trophy Points:
    0
     

Share This Page