SVS PB10 at reference level

Discussion in 'Speakers' started by Himanshu_S, Mar 20, 2005.

  1. Himanshu_S

    Himanshu_S Stunt Coordinator

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    I would like to know if SVS PB10 can handle reference level. If not, why not? What good is a subwoofer if it can't reach reference level while all your other speakers are able to? If yes, is there a possibility of damaging the sub at that level?

    I know one poster melted his SVS when watching AVP at reference level, but that was because people have said the sound was already mastered at +10 db so he was really watching at +10 db reference level.

    Currently I watch about 10 to 15 db below reference level, however, during "The Incredibles" movie there have been times where the SPL was measured at 100db(especially when the ball hits the ground or big explosions). The sub did an AWESOME job at this level but I want to know if the SVS can handle that movie at reference level. I am not crazy and I am not rich so I won't try that until I know for sure it can handle it [​IMG]

    Thanks for the replies and many thanks to SVS for making the PB10. It is one kick *** sub.
     
  2. Ryan Tsang

    Ryan Tsang Second Unit

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    Too hard to answer. How big is your room? Where are you measuring from? Where's the sub? Reference at what frequencies?

    Ask SVS directly. They should be able to help if you provide them with this sort of info.
     
  3. Edward J M

    Edward J M Cinematographer

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    Reference Level requires clean bass peaks of approximately 115 dB at the listening position.

    While the PB10-ISD is indeed a very impressive performer for a 10" woofer, it cannot deliver that kind of sound pressure in an average size room at the listening position.

    It is difficult to damage the PB10-ISD or make it misbehave, so you can probably turn the volume up louder, but the sub will simply go into dynamic compression and not play any louder....so what's the point.

    As you have found, 10-15 dB below RL (100-105 dB peaks) is the sweep spot for this subwoofer. If you want more dynamic output capability, a second co-located PB10-ISD will provide you with another 6 dB of headroom. And if you want true clean RL capabilty in a mid-size room, you are looking at dual 12" woofers.
     
  4. BrianWoerndle

    BrianWoerndle Supporting Actor

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    To achieve true reference level at the lowest depths is extreamly hard, and therefore expensive. The PB10 is an amazing performer for its price, but to expect it to hit true reference levels is asking a bit much.

    It took me 2 16-46CS+s with the Samson S1000 (500 watts each) to achieve reference level bass in my room (all the way down to 14hz). 1 SVS just couldn't quite cut it.
     
  5. Himanshu_S

    Himanshu_S Stunt Coordinator

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    Do you mean the reference level for PB10 as in only the PB10 is on and has to put out 115db? or do you mean when all other channel's are also on, like during a movie? I am confused by this. I was measuring the 100db while other channels were on. I thought when I calibrated my speakers to put out 85db at 0db, then 0db on my receiver is the reference level.

    BTW, my room size is 20x12x12 with opening on the right to the upper level. My listening position is at approximately 17 feet. When measuring the 100db, I did it from listening position and measured the peak SPL during explosion scenes. Hope this makes sense.

    By reading the reviews by Ed, it looks like the 105db limit of PB10 is when it is by itself, not with other speakers running. This would mean that 115db for me would be easily achieved without having the sub go crazy. Am I missing anything here? I mean if I crank it upto 0db, I am probably going to hit 115db peak when watching a movie, but that doesn't mean that my sub is going to put out 115db. is this correct?

    I would also like to know if increasing the volume on the PB10 is better than the increasing the subwoofer level in the receiver? In Ed's review, he mentioned that increasing the subwoofer level in receiver can lead to pre-out signal distortion. My sub volume is currently set at the half way but my receiver's subwoofer level is at more than half, higher level than my other speakers.
     
  6. Edward J M

    Edward J M Cinematographer

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    The highest sound pressure peaks will come almost entirely from the subwoofer. While passages in the midrange and highs may seem louder (since your ear is more sensitive to these frequencies), they are not.

    If your speakers are set to small, the subwoofer has to handle redirected bass, and the LFE channel. Dolby Reference Level specs 105 dB peaks from the surround channels, and 115 dB peaks from the LFE channel.

    So with the speaks set to small, the subwoofer will be almost entirely responsible for generating these sound pressure levels. My room is 12x18x8 and the sub is 11 feet from the listening position, and the PB10-ISD sounded dynamic and comfortable at 100-105 dB SPL peaks. If pushed any harder, it politely goes into dynamic compression and refuses to play any louder.

    You are correct in saying that calibrating with Avia to 85 dB at MV 0.0 is theoretically Dolby Reference Level. However, there is one variable on the whole RL concept, and that's the actual DVD mastering level. I wish I could say that setting the Master Volume to 0.0 after RL calibration with Avia always yielded sound pressure peaks of 105 dB in the surround channels and 115 dB in the LFE channel every time for every Dolby Digital DVD, but it just isn't true. Some DVDs are mastered very hot, and other ones are not.

    Underworld is a perfect example - you will hit Reference Level sound pressures on Underworld at around -14 to -13 on the Master Volume if your system is calibrated to RL with Avia. This is strictly the result of the recording studio mixing the overall playback level considerably higher than it should be.

    In the end, RL playback is best determined with the sound pressure meter instead of blindly following the Master Volume setting, because we cannot control the DVD mix level. If you are hitting peaks of 112-113 dB on the SPL meter, you are playing at/near RL.

    And I can virtually assure you the PB10-ISD will not be able to generate more than about 103-104 dB SPL peaks in that size room 17 feet from the subwoofer no matter where you set the MV control. It's not the fault of the subwoofer (the PB10-ISD has extraordinarly high/clean output for a 10" woofer), it's just a matter of physics and air-moving capability.

    If you want true RL capability (115 dB peaks at the seating position) in a 3,000 ft3 room 17 feet from the subwoofer, you will need something like a PB12-Plus/2 or dual 25-31PC+ running in the 25 Hz tune (all ports open).
     
  7. VinhT

    VinhT Second Unit

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    If I recall correctly, the "melted" SVS was simply a case of customer abuse (in addition to not using a proper infrasonic filter).
     

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