Does Setting your system to Reference actually give Refrence levels at output?

Discussion in 'Archived Threads 2001-2004' started by Kirk Mango, Jul 19, 2002.

  1. Kirk Mango

    Kirk Mango Stunt Coordinator

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    There have been several posts on SPL readings and Reference levels on HT systems, some of which I have initiated, on this board over the last couple of weeks. Much of this information has raised some questions for me and what it all means. As mentioned in earlier posts, I have my system set using the Ref30 test tones to 74dB on all speakers with the sub set at 72dB to compensate for the SPL meter I use. When I use the AVIA disk test tones and turn my volume to 0dB on my preamp I get a reading of 84dB on my SPL. All of this seems to indicate that my system is set Pretty close to REF levels. However, isn't this all relative to how hot a DVD (or CD) is mixed. For example, I am sure everyone has noticed that some DVD's (and CD's) sound lounder then others when played at the same volume level on the preamp (differences are much more apparent in general dialog on DVD's rather then during explosions). The SPL meter bears this out by showing a higher dB reading for the hotter DVD's (CD's) using the same volume setting. What this would seem to indicate to me is that Reference levels are only relative to the specific DVD (CD) that you are using at the time and not to the system as a whole. Even if you set all your speakers to 85dB (Avia) and/or 75dB (VE) you cannot just set your preamp's volume to 0dB and expect to get accurate reference levels from your system on all DVD's (CD's) because one DVD may be much hotter (or softer) then the next forcing you to manualy adjust the volume accordingly.

    If this is correct then it would seem much more important to balance all speakers in your system rather then placing to much importance on the 75/85dB standard and then adjust your volume to Reference levels (or more importantly, the level you enjoy listening to). Am I understanding this all correctly? Any other thoughts on this would be appreciated.

    Kirk
     
  2. John Garcia

    John Garcia Executive Producer

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  3. Sebastian

    Sebastian Second Unit

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    One reason, people use ref level as a guideline. For example to ask questions and compare system performance. If I said my sub starts to starts to distort while watching the TPM pod race scene 5dB under ref you should know exactly how loud I was listening it to.
    I agree that leveling all your speakers is the most important thing.
     
  4. Kirk Mango

    Kirk Mango Stunt Coordinator

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    Ok then, That means that when you walk into a Mid-highend store and the salesman puts on a DVD, sets the preamp to 0dB and states that you are listening to this movie at reference levels (or at the level that the director intended) he or she is making an incorrect assumption. There is no way to know if he is getting reference levels out of the system unless you test the dialog and peaks using an SPL meter. Is this a correct statement?

    I was in a store the other day listening to Titan A&E at 0dB on the preamp. I should add that this was blisteringly and uncomfortably loud, much louder then I have ever played it on my home system (around -14db on my preamp). The largest peak on my spl during the explosion sequence of this film was around 100dB. It would appear that even at this very very loud volume that the peaks did not reach the 105/115 DD reference levels, however, the salesman stated just what I said in the first paragraph, that this was reference levels and exactly how it was heard in the theatres. (I would guess the regular dialog levels to be in the upper 80dB range.) This can make for a very confusing understanding of what DD reference levels actually sound like. If my measurements are correct, and the system was set up correctly, then the system was below Ref levels at 0dB preamp Vol. setting. It is vary hard to believe that anyone can actually listen to a movie at True Reference levles, it would be much to loud. Can anyone else shed more light on this.

    Kirk
     
  5. John Garcia

    John Garcia Executive Producer

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    As you said, it also depends on the movie. My calibrated ref is -8 on my receiver, but I normally listen to most things at -20 to -15, because -8 is too loud for most material. Titan:AE is about -15 for me, and will be fairly loud.

    Good examples of varied mastering levels are SW:TPM and Nin Inch Nails - All That Could Have Been. TPM I have to crank up a bit. I have listened to it at ref and even above, because it is mastered a bit low, so it can be cranked up, I guess. The NIN DVD however, is already loud at -30, and would be painful at -15.

    I listen at whatever volume suits me.
     
  6. Mark Seaton

    Mark Seaton Supporting Actor

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    Hi guys,

    "Reference Level" does in fact exist. This allows the system to be calibrated to produce the same level to the listener as the mixing engineer was listening to. Our test tones at -30dB allow for a point of matching. Now, unfortunately it gets a bit more complicated.

    First off, most rooms aren't as well treated as a studio, and depending on the size of the room, few can cleanly produce peak reference levels. Remember that just because the system can peak at 105dB doesn't mean they use that all the time! Reference level can sound great on a capable system.

    Regards,
     
  7. Vlad D

    Vlad D Screenwriter

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    I calibrated my system to reference using the VE disk. And, I agree that different DVD's have sounded louder at the same volume level on my receiver. But, could it be that it was louder because that is how the mixing engineer intended it to be?
     
  8. Kirk Mango

    Kirk Mango Stunt Coordinator

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    I suppose that is a strong possibility Viad, however, when your dealing with normal conversation levels in a DVD and the dB level at the listening position ranges from 58 to say 70 depending on what DVD you are watching when the preamp is set at the same Vol. level and the system is set to reference. Just an interesting topic for conversation.

    I suppose some of this dB fluctuation can be accounted for by the varying deepness of the actors voice. Deeper voices tend to read higher dB levels on the spl meter then do voices of higher frequency. Say the deference between two male actors talking and two female actors talking. Well, just throwing out some interesting observations I have had with regard to reference levels and systems.

    Kirk
     
  9. Jonathan Smith

    Jonathan Smith Stunt Coordinator

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    The reason for the difference between DVDs is indeed because of how they are mixed. Dolby Digital tracks have a maximum allowable volume (we'll call it 0). Everything else is relative to that value (-30, for example). When you set reference level, you setting up your amp/speakers such that the maximum SPL at the listening position (which corresponds to 0 mentioned above) is 105 dB (115 dB for LFE). The "average" level of dialogue in the movie can be whatever the mixing person decides. Normally, they choose something like 75 dB to allow a lot of headroom for loud sounds, but there is nothing that says it can't be quieter or louder.
     
  10. Mark Seaton

    Mark Seaton Supporting Actor

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    ...and Jonathan nails it on the head.
     

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