Finally got Avia, so another "Good God Reference is LOUD" thread.

Discussion in 'Archived Threads 2001-2004' started by Dustin B, Feb 23, 2002.

  1. Dustin B

    Dustin B Producer

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    Finally got the disc, got everything level match and determined what reference level was on my system (I normally watched movies at 48-52 on my onkyo's 0-72 scale, reference was at 66). Then proceeded to watch the lobby shooting spree at reference. Made it through it. Spl meter on A weight stayed above 90dB the entire time and hit peaks just past 100dB. Way too loud for me. I think I'm gonna be rethinking my plans to build a subwoofer capable of true in room reference levels, I just don't need it.
    Mind you my receiver generates audible hiss at my listening position when I have it this loud and my speakers begin to sound very harsh at that level. So once I upgrade my speakers and amp, I might end up likely it a little closer to reference levels and then my sub plans might not go completely out the window.
    Surprising part was that my center was at +3, mains at +7, surrounds at +4 and the sub was at -12 (as low as the receiver would go) and it was still hot, so I had to turn the gain on the amp down. Gotta love the Tempest [​IMG]
    I also learned I have a bad room mode at 40hz, and I'm not sure if the null at 80hz is due to a room mode or my mains not making it down to 80hz with enough oomph.
    Lots of fun left to be had with this disk though [​IMG]
     
  2. Nick P

    Nick P Second Unit

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    Dustin, you're a wimp![​IMG] Peaks of 100db are "way too loud"? I'm listening to the Fight Club airplane crash with peaks of 114db with the volume set 6db under "reference" on my receiver. Twin 20-39CS+ S1000 combo. What's that? I'll go deaf? Speak up, I can't hear you![​IMG]
     
  3. Tony Genovese

    Tony Genovese Supporting Actor

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    You gotta calibrate the system at C not A weighting.
     
  4. Dustin B

    Dustin B Producer

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    I calibrated on C weighting. I just put the meter to A weighting to see what the lobby shooting spree was like at reference in the range that can really do some damage to the ears (guess I should have explained that reasoning). I don't know if I'll try it again, but I'm sure I'd have seen peaks over 110dB as well if I had the meter on C weighting.

    I've had the meter register 111dB from the ball explosion in the THX intro to TPM. I don't know for sure what frequency that explosion is, but I'd guess that number has to go up at least 3dB to correct for the rat shack meter. If a large part of that explosion was under 20hz then it would be closer to 7-9dB more wouldn't it. Loud low bass doesn't bother me, but those gun shots in the lobby shooting spree at 100dB, just too much.

    They say it takes 2 hours a day of A weighted 100dB to cause permenant damage. So although I guess it is safe, it was just uncomfortable for me, making it not enjoyable. Whether it's because it was just to loud, or my poor Onkyo 575 and Klipsch KSB1.1 mains just can't play that loud cleanly I won't know until I upgrade. Until then I guess I'm a wimp :p)

    For those interested, the rest of the scale is like this:

    A weighted dB / time per day to cause damage

    105/1h

    110/30min

    115/15min

    120/you will damage your hearing
     
  5. Dustin B

    Dustin B Producer

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    Guess I'll also mention that my dad was in town today. I'd run the scene once when he wasn't at the house. Sat him down when he got to the house and it was less than 3 seconds after the shooting started that he told me to turn it off :p)
     
  6. Harry Lincoln

    Harry Lincoln Stunt Coordinator

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    The TPM THX intro ball explosion = 120.5db (C weighting)from two shiva sonotubes tuned to 16.5hz.

    I once disconnected the 5 full range speakers and cranked the subs way over ref level and played the TPM THX intro, It frightened the shit out of me and I dropped the SPL meter and dived for the mute button on the remote. I didn't get the measurement from the SPL meter but it was LOUD. Im not game to do it again in case the house falls down.

    Harry
     
  7. Glen_L

    Glen_L Stunt Coordinator

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    For what it's worth, I played The Matrix at reference levels (calibrated to 85dB for all speakers on Avia) with my nOrh 4.0 speakers all about 1m away from me and the twin 25-31CS+ subs about 3m away in the corner. The 4.0s are each driven by a nOrh LeAmp monoblock, and an Integra 6.2 receiver serves as pre/pro.

    It was LOUD, don't get me wrong, but I didn't find it uncomfortable. I think distance to the speakers plays a large part, at 87dB sensitivity the speakers need about 64W (which is no problem for the monoblocks) to reach 105dB at 1m. Everything sounded "right"--dialog was at a very normal level, explosions and gunshots were realistic, and quiet scenes were dead silent when needed (no audible hiss).

    I'm not sure how far you are from your speakers, but distance makes a big difference in how hard you have to push them. If you're too far away and your speakers are not highly sensitive, they'll sound strained at reference level. Reference comes in at volume 50 on my Integra, with all mains at about +8dB (they are equidistant from the listening position), subwoofer at 0.
     
  8. Dustin B

    Dustin B Producer

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    Glen,

    Ya, distance definately helps. My room is 18ft long and 12 feet wide, with the an 8foot of so opening to the immediate right of my equipment. The KSB1.1 (mains) are rated at 92dB/W/m and the SC1(center) is rated at 95dB/W/m. How accurate these numbers are I don't know. I'm 13' from my mains and 11.5' from my center. 13' is almost 4m. I'll guestimate that distance follows the same dB rules as watts.

    So at 1m

    92 = 1

    95 = 2

    98 = 4

    101 = 8

    104 = 16

    then at 2m

    104 = 32

    then at 4m

    104 = 64

    The onkyo claims 70x5, so I should be able to do it. Ah well, I'll eventually upgrade, I'll see what happens then, if it's just too loud, or my current system just can't do reference cleanly enough.

    Harry,

    dual Shivas have a 1/2L displacment advantage on my Tempest. I'm tuned to pretty much the same freqeuncy. I hit that 111dB before I calibrated my system. That was with the onkyo set to 55, the gain on the plate amp set at about 8/10 full, and the sub level on the receiver at 0. I don't know if I'd want to take it up to 10/10 and +12 though.
     
  9. Glen_L

    Glen_L Stunt Coordinator

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    Actually, you give up 6dB for each doubling of distance anechoically. You won't lose quite that much in a room because of reflections, but it's a minimum you can start by. So, considering you'd lose ~12dB at 4m:

    1W: 80dB

    2W: 83dB

    4W: 86dB

    8W: 89dB

    16W: 92dB

    32W: 95dB

    64W: 98dB

    So, in theory (and assuming sensitivity and amp wattages are true), you should expect at least a clean 98dB from each of your mains. Asking them to play true reference levels (105dB peaks) may be pushing them too hard.
     
  10. Dustin B

    Dustin B Producer

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    Thanks, that's the number I needed to know. I learned the dB/W ratio a long time ago. Don't ever remember seeing someone declare the distance drop off though.
    So yep, it would appear part of the problem is my speakers and amp. Oh well, I'll eventually fix that problem [​IMG]
     
  11. Greg Br

    Greg Br Second Unit

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    Question about reference volumes. If you calibrate your system propoerly, for me that is at -27 on my Yamaha, then if you are playing a dvd at -27 then are you listening to it at reference level. I assume so but for this is loud, theater type loud but is not out of contol loud. I have a big room wih two openings and about 9000cf, and sit 12 12 feet from the subs and 8 feet from the mains.
     
  12. John Stone

    John Stone Supporting Actor

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  13. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

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    I try to keep the levels down to protect my hearing, but my car hits 140-145 quite easily and I love to give demos [​IMG]
     
  14. Bill Kane

    Bill Kane Screenwriter

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    Yes, I have tinnitus, too, and it seems to be HT induced.

     
  15. Dustin B

    Dustin B Producer

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    I'm glad you guys chimed in. Not glad you have tinnitus, but it servers as a great reality check to others. I'm not sure if I ever, even after getting new speakers and amps, would have listened at reference levels. But after your warnings, I think I'm gonna stick to calibrating to 75dB instead of 85dB with Avia and use that as my reference level, and never exceed it. Still plenty loud enough for me.
    Here's a link to a really simple to use tone generator:
    http://www.nch.com.au/action/tnsetup.exe
    Try what John suggests. I am right now. This would most definately suck.
    Bill&John, since you have likely read and heard more about that OSHA scale. Do you think it is conservative or liberal with it's numbers?
     
  16. Bill Kane

    Bill Kane Screenwriter

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    god knows, they are guvmint figures! Just dont take 'em as a free pass to 15 minutes of crash-boom because the "experts' say so.

    Like, when we talk about SUB crossover, there is no brick wall, but rolloffs. Apply this concept to these loudness scales ("oh, it's just 14 minutes now, so I'm ok").
     
  17. AntonS

    AntonS Stunt Coordinator

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    I work in hearing health industry. Apart form titanus, if you listen to high SPL regularily you are very likely to develop sensorineural high frequency (4KHz+) hearing loss by the age of 50 (in some cases earlier). Be reasonable, otherwise you may need to drop this hobby as good sound will not matter anymore. You may even start liking Bose...
     
  18. Nick P

    Nick P Second Unit

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    When we are talking about 100, 110, or even 115db "peaks" they are by definition the "loudest" part of a movie and usually only last a few seconds. It's not like the entire movie is playing at 115db. With peaks of 110db most of the film is probably only hitting 85-90db I would guess? A few seconds of 110-115db spread throughout a 2 hour movie wouldn't cause much if any damage would it? Listening to loud music for long periods of time is another matter. Constant high SPLs in that case.

    John, I would guess your tinitus was caused by the keyboard and shrills of the electric guitars? Probably not the bass? I was under the impression that the clean, low bass was one of the safest frequencies to listen to at high SPL.
     
  19. John Stone

    John Stone Supporting Actor

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