SVS 16-46PCi SPL Question

Discussion in 'Speakers' started by Matt Amato, May 27, 2004.

  1. Matt Amato

    Matt Amato Stunt Coordinator

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    I'm moving into a new house come August and I'm ready to invest in a nice 5.1 setup. I have already decided to buy an SVS, and originally just assumed I'd get either the 25-31 or 20-39. But I now realize that the room where the HT is going to go is relatively small (under 200 square feet (maybe even 150) rectangular with two exits, see pathetic diagram below, I don't have the exact measurements handy) and was wondering if a single 16-46 would be able to reach reference level in the room. If so, I would probably spring for the 16-46, if the budget allows. If not, then I'm sure the 20-39 (or 25-31 tuned to 22) would be more than adequate. I would love to use the small room size to my advantage in order to achieve truly deep base, then the plan would be to buy a second 16-46 if I ever moved to a larger room.

    [c][​IMG][/c]
     
  2. TimRP

    TimRP Stunt Coordinator

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    Assuming 8 foot cielings, your at 1600cubic feet or less, which is small. I think one 16-46 would be more then enough.
     
  3. Matt Amato

    Matt Amato Stunt Coordinator

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    Cool, that's what I was hoping to hear. I'm going to take more exact measurements before I make my decision, but can anyone give an educated guess as to the max size (cubic feet) of a rectangular room that a single 16-46 could handle?
     
  4. Craig Chase

    Craig Chase Gear Guru
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    At least 2500 ^3 feet...
     
  5. ChrisBee

    ChrisBee Stunt Coordinator

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    I see 105dB regularly with my 16-46 PCi on rock music. My room is open plan with the downstairs lounge (via an open stairwell) and our attic listening room about 30 feet long by 18 feet wide. In your room I would expect 110-115dB with ease if my limited experience is anything to go by.

    I haven't tried to reach its limits but can assure you that it rattles things all over the house with ease. My wife even called me out to show me her seed trays were rattling in the greenhouse! She thought it was funny. [​IMG]

    On films it is just awesome. When we're not grinning like kids we're cowering under the furniture! [​IMG]

    ChrisBee

    http://mysite.freeserve.com/svs_pci_music/index.jhtml
     
  6. steve nn

    steve nn Cinematographer

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    If your seating were included in your drawing Matt, where would it be?

    Can you close the entrances?

    What level ceiling does your room have?

    Any idea where your sub placement will be?
     
  7. Edward J M

    Edward J M Cinematographer

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    With a typical sub-to-seat distance (maybe 10-12 feet), I think clean 115-120 dB bass peaks would be tough for a single 16-46PCi.

    Would a 16-46PCi be loud, clean, powerful and totally acceptable in that size room? Yes, without question. But if you want "true" RL playback capability, you'll probably need to step up to a Plus cylinder.

    Many people are perfectly happy with clean playback levels at -10 RL, where you're looking at maybe 105-110 dB peaks at the seat, and the 16-46PCi could deliver that in your size room.

    Also note you'll get lots of room gain down low, so you'll probably be able to use a 20-39PCi and still easily see useable response to 16 Hz.
     
  8. steve nn

    steve nn Cinematographer

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    With a typical sub-to-seat distance (maybe 10-12 feet), I think clean 115-120 dB bass peaks would be tough for a single 16-46PCi.
    __________________________________________________ ________

    Ya that was where I was drifting to Ed. If Matt's seating is up against the back wall and 8' ceilings? Then he definitely can push things a little further but not reference.
     
  9. Sami Kallio

    Sami Kallio Screenwriter

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    If you calibrate the sub to reference levels, what will happen? Does the sub bottom out or will it simply not push enough air to reference level? The reason why I am asking is that I have 16-46PCi as well on bigger room than Matt and I have calibrated the system with DVE, speakers to 75dB and sub quite hot to 92dB. Listening at the reference level in which the speakers were calibrated to, SVS sounds fine to me but am I reaching reference levels even with the calibration? Would the only way to know be measuring the SPL output during playback? Am I missing something?

    Does it help that I have blackout lining across the room blocking two entrances and cutting room size by a good 300-400 ft^3 from 2800 ft^3?
     
  10. steve nn

    steve nn Cinematographer

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    It sounds as though you have a plus 5 db sub calibration going then Sami. +7 db meter correction factored in. (-12 db DVE .1 channel calibration) Ed did a good Thread pertaining.

    Sami are you saying with a +5 to 7db sub calibration you can watch action movies at -0 with out your 16-46 sub bottoming out in the heavy bass scenes?

    Before a SVS bottoms out it will usually hit a point where it just wont go any louder. Add a little gain and no response. Add a little more and it will bottom.
     
  11. Sami Kallio

    Sami Kallio Screenwriter

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    I was thinking about that myself but after I tested that famous Darla scene (Finding Nemo, chapter 25) and pumping up the gain from the receiver increased the volume, I was a little confused. It's at -9 from the receiver and I did go up to +5, +6 without bottoming out the sub. Sub gain is at little over half way.

    I guess the only way to find out would be to measure SPL at bass heavy scenes then.
     
  12. ChrisBee

    ChrisBee Stunt Coordinator

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    This raises an interesting point considering the ever heavier and ever deeper bass offered by both films and music. The boundaries are really being pushed here and will endlessly chase the availability of quality subwoofers to reproduce it. Presumably the rest will just go up in smoke? :b

    What exactly is reference level on favorite bass scenes in actual dB in the room?

    I run my 16-46 hot by simply cranking it up two notches (from the musically flat response) on the gain control.(using high level connections)

    It hasn't bottomed out because I'm rather afraid to push it any harder. It does it all so effortlessly that the fear is it will find its limits suddenly and catastrophically.

    110dB is obviously within its capabilities. I've seen that on the meter a number of times without obvious stress to the 16-46. (this ignores the meter roll-off! WYSIWYG [​IMG] )

    Is it even possible to pin down a safe (in-room) dB level for popular subs?

    ChrisBee
     
  13. Matt Amato

    Matt Amato Stunt Coordinator

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    Unfortunately, I don't have any of the exact dimensions for the room. The place I'm moving into is currently being remodelled but I wanted to start doing some preliminary investigation into sub choice. Next time I visit the new place I'm going to bring a tape measurer and get some exact dimensions, then I'll probably draw up a floor plan and try a couple different layouts for the gear. For those that asked, I can't close up those entrances, and I would probably place the TV along the left wall, couch along the right wall and the sub in either the top right or top left corner. I could conceivably put the sub next to the TV and not in a corner, but I have to wait until I get more exact measurements to see if that would fit.
     
  14. Matthew Todd

    Matthew Todd Second Unit

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    Assuming that when you calibrate the sub, it accounts for room gain at the various frequencies (I know this really is a BIG if), then the highest SPL that should EVER be reached at reference level in the room is I think 115dB if you're only looking at the LFE channel, and if you include rerouted bass because of the receiver's/processor's bass management I think the maximum SPL at reference level is 126dB (although I can't remember how one gets to that number).

    Matt
     
  15. johnny..bon

    johnny..bon Stunt Coordinator

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    My room is also small 15 x15 x8. I started with a 25-31pci tuned to 22hz and found it to be too loud in the 30-60 hz region. I then switched to a 20-39pci tuned to 17 hz and found this to be perfect for my room. I run it hot and I don't think I can ever bottom it out.
     
  16. steve nn

    steve nn Cinematographer

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    WHAT THE HECK IS REF LEVEL ANYWAY?

    In a nutshell, Dolby specifies an ideal playback level for their theatrical soundtracks and for the mixing envirinments in which those soundtracks are created. So, unlike music, movies are technically created with a standard playback level in mind. Based upon this intended level, dialog and effects are mixed at very specific levels to offer similar sound levels across various dolby soundtracks.

    This playback level is basically defined as 105db peak level from any (((single speaker))) in the dolby playback system. By using tones on VE or Avia- they are specifically defined to give you this playback level.

    Since VE's test tones are exactly 30 steps below the maximum level - calibrating that tone to 75db of SPL in your room means you have calibrated your system to playback 105db when given a peak signal.

    Similarly, since Avia's test tones are exactly 20 steps below the maximum level - calibrating that tone to 85db of SPL in your room means you have calibrated your system to playback 105db when given a peak signal.

    So, if you calibrate using those tones, and their intended target level (75db for VE or 85db for Avia)- that position on your volume knob will be dolby's ref level, providing you with a system that is now calibrated to offer 105db peak output.

    Most home users don't listen at dolby's specified levels- but often it is a good point of ref when seeking help or advice on forums such as this one.

    -Vince


    -----------------------------------------------------------

    WOW! I am very surprised to hear what you can do with the 16-46. Maybe I need Sami to come on over and calibrate my subs?

    Seriously though. Sami do you have your 16-46 calibrated close to seating?

    Can you watch SW II at -0 on the first Fly-By? I can look up the time stamp if needed.
     
  17. Sami Kallio

    Sami Kallio Screenwriter

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    I looked that scene and the dB output is 106-107dB according to RS SPL meter (unfortunately they didn't have analog). Don't know how good of a method this is to measure. Location was at my seat, about 5m away from the sub.

    Next thing I did was disconnected all other speakers and ran LOTR:FOTR opening battle. Max dB with just the sub was 102dB but it looks like at -9dB it stops producing more. Blackout lining, when I removed that, SPL dropped to 100dB. Ring drop was around 94dB.

    Now the fly-by, 107dB at -12. Same at reference.
     
  18. steve nn

    steve nn Cinematographer

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    Thanks Sami[​IMG] Very interesting. Just goes to show you the stamina a SVS has with out using a limiter. You figure LOTR is mixed about 4 or 5 db's hot so you are getting close to reference at -9. I tried the ring drop at -0 a few times a while ago and man is that loud.

    >>>Now the fly-by, 107dB at -12. Same at reference.
     
  19. Sami Kallio

    Sami Kallio Screenwriter

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    I will have to convince my friend to bring his 20-39PCi (tuned to 17Hz) this weekend so we can pair the two for a test drive. Otherwise I will have to bite the bullet and order PC Ultra or one of those SS's (or two). [​IMG]
     

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