Newbie calibration questions...

Discussion in 'Archived Threads 2001-2004' started by JohnGoggan, Aug 16, 2002.

  1. JohnGoggan

    JohnGoggan Stunt Coordinator

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    Hi all! I purchased a low-end system (the Sony HT-DDW740 HTIB package) two days ago -- and sat down to calibrate it as best I could yesterday. I used DiscWasher's "home theater setup disc -- silver edition" for the calibration tones (mainly because I already had it from a while back -- I'll pick up Avia's disc sometime in the future hopefully).
    In any case, I have a few questions/concerns...
    1. This disc doesn't give a specific db level to go for -- it just says that it should be "between 78db and 85db". The DiscWasher disc plays pink noise for the calibration. I started with my first speaker (front left) and had to turn up the master volume to 60 (out of 64) to get to 78db on my Radio Shack meter (which is 11 feet from the front speakers). Is this normal? It just seemed that I had to give almost all of the possibly master volume in order to get to just 78db. Maybe that is normal for a low-end system like mine?
    2. Once I had that set, I had no problems adjusting all of the other speakers slightly to get them all to about 78db -- EXCEPT for my front center speaker. When the pink-noise starts, it is at about 74db. It then gradually gets louder over a 10 second period until, at the end, it is at 84db! In other words, it increases in output as it plays. None of the other speakers did this -- so I am unsure if it is a problem with the DiscWasher test (which I doubt) or something else. Do I have a problem with my receiver?
    3. Now, just a question in general on something that confused me. In the FAQ section on calibration, it says that "Some people choose to set their master volume to a 00 position and adjust the levels from that point-- which is fine but not at all necessary." Um, do they just mean START the master volume at 00 as opposed to something else when searching for the right level for that first speaker? Otherwise, I don't see how you can leave your master volume at 00 and adjust your speakers unless I am missing something significant. [​IMG]
    Thanks!
    - John...
     
  2. JohnGoggan

    JohnGoggan Stunt Coordinator

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    Oh -- one other question... My subwoofer has a min-to-max adjustment pot on it. Should I use THAT to make level adjustments or the SW level output on my receiver? And, if I am to make the adjustments on my receiver -- then where should I put the min/max pot on the SW itself? Should I leave it all the way at min? Or center it? Or adjust it in some other way?

    Thanks!

    - John...
     
  3. ColinM

    ColinM Cinematographer

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    1. Yes, normal. To calibrate to reference, you are using a signal recorded at -20 or 30 db from the max. If the recorded signal was at -0db, it would be as loud as possible for the source (cd, etc).

    2. Weird! No idea.

    3. I set my volume to -0db, since it reads out that way. I then 'tweak' each speaker's level up or down to get the proper level. I wind up with (L-C-R-SL-SR-SUB) +3, -5, +3, +1, -0, -5. When the master volume is at zero, my DVD's theoretically play back at reference level.

    (4.) I set my sub's receiver adjustment to 3/4 of the way down (-5 out of a range of -10 to +10) and twist the pot till it's reading about right on with the meter.

    Good Luck!
     
  4. JohnGoggan

    JohnGoggan Stunt Coordinator

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    Ah! Now I see... I think... So -- you have a receiver that allows you to SET a specific volume as "0"? And you set your reference to that, right? And then you normally listen at (-something) db, yes?

    So, when the FAQ talks about people setting their volume to "00" to do the calibration, that is actually not "0db" (meaning silence), correct?

    I don't think my receiver has that option... It just seems to go from 0 to 64 as a volume level.

    - John...
     
  5. Greg*go

    Greg*go Supporting Actor

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    You got it John. Next time you're in a store look at a Yamaha receiver. You'll notice that the volume starts in the negatives. This doesn't mean that its not putting out any sound, it's just -64dB below the supposed reference level. Sony receivers don't do this, but you'll find a bunch that do.

    And you might want to give sony a call and explain the center speaker problem to them. It might be a problem with your receiver.
     
  6. Jason Co

    Jason Co Second Unit

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    Greg,
    Let me just make sure I have this right. I am having a hard time wrapping my brain around this concept. I have a Denon 3802, I calibrate at 75db using an spl meter. SO what I want to do is turn my receiver volume up to 00 which is considered ref. level (105db?). Then I use the individual plus minus control on each speaker with a test tone and adjust them so they read 75 dbs?

    I guess the issue I am having is if I calibrate it to 75 dbs at a certain master volume reading, why won't that level change when I adjust the master volume? For example, if all my speakers level out at 75db on the meter at a master volume of 00, when I turn the master volume to say -15 and check on the meter what should it read?

    I think I am making this more complicated then I should but I want to get it right and understand it as well.

    Jason
     
  7. Ted Lee

    Ted Lee Lead Actor

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    if you haven't yet, read this thread:
    http://www.hometheaterforum.com/htfo...553#post650553
    other than that, i don't think you need to put that much emphasis on "reference level". i'm not even sure i completely understand it myself, but it seems to only be useful if you're comparing two systems.
    all i did was set my spl meter (c-weighting, slow) and crank up my receiver's MAIN volume knob until i got about 80db on the meter. then i started using the receiver's INTERNAL adjustments to tweak each channel until my spl read the same for all channels.
    it's that easy...you can certainly get more indepth if you want, but it may not really be necessary.
    [edit] - oh yeah...to answer your original questions:
    1. it sounds about right. i wouldn't recommend cranking the internal adjustment too high...i think that may cause distortion. remember, you're not cranking really clean hi-power. if you try to "push" the amp too hard, you'll end up distorting the sound and possibly blowing your tweeter.
    2. that's bizarre. i've never heard of a receiver slowly bumping up the center. sounds suspect...call tech-support.
    3. the whole point is to find a "reference" number for your calibrating. you could just as easily use "-10" or "+15" - the number itself doesn't matter. it's just so you have a "starting point"
    4. i've heard most people say you should crank the sub up pretty high on the main knob, then use the receiver's internal adjustment to fine-tune. but i've never owned a sub so i can't say for sure.
    good luck!
     
  8. Bill Kane

    Bill Kane Screenwriter

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    And when you've set your "reference level," say to 60 on the Sony AVR, you likely -- like most others -- actually will listen about -10db to -15dB lower than this for more comfortable actual room playback.

    For the Sub settings, it is usually suggested to adjust the two controls to end up with the sub amp set about 3/4 up and the receiver (remote) level at the 1/4 to 1/2 level for optimum line-level voltages. (My AVR sub setting goes from -20 to 0; I am set at -18.5dB. This gives me plenty of room to adjust/boost the bass/lfe when I wish.)
     

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