Calibrating my new setup + extreme lack of bass.

Discussion in 'Speakers' started by Jay_Via, Sep 13, 2006.

  1. Jay_Via

    Jay_Via Stunt Coordinator

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    Hey all, wanted to post and get a few opinions as to what is going on. Recently put together a dedicated theater room in my basement, and now that its up and running im trying to get the speakers and sub calibrated.

    Heres some basic info:

    Room is 27L x 13W x 7H. Acoustical tile drop ceiling and carpet (no pad) installed on the floor. Room has two rows of seats, one set of 3 lane leather recliners and the second row is 5 re-done theater seats. First row is about 12.5' from the screen and front speakers and the second row is on a platform directly behind the first row. The room has 3 doorway openings, however, two have doors and the third is the stairway entrance into the room.

    Equipment:

    HK AVR 435
    Athena Technologies AS-F1 (Fronts)
    Athena AS-C1 (Center)
    Athena AS-B1 (Surrounds)
    SVS PB10

    I started calibrating the system and want to make sure im doing it right.

    All speakers are set to small in the HK, Sub is ON.

    I have the Radio Shack SPL meter set to C-Weight and Slow, 70db. I started the HK's master volume at -10dB and then began the test tones from the HK. I have the speakers calibrated at 75dB according to the SPL meter, with just a slight adjustment to each speaker (using the dedicated channel volume through the receiver. I started the sub at 1/4 on the gain and
    -5dB for a level, and got it to calibrate at 78dB.

    Popped in a movie (tried scenes in Blade, Matrix, Underworld) and was mildly disappointed. I get almost no bass at all, like i have to really strain to hear it, and i dont feel it at all. I turned the gain up a bit and can begin to feel it, however, to really "feel" it like i think it should sound i have to put the gain up to about 1/3 and turn the HK's sub volume to +5dB. Does this sound right??

    Is is possible the PB10 just isnt large enough for the room? Normally the PB10 is upstairs in my living room (which is a similar size, with more openings) and it seems to rock up there. I tried the sub in several locations without much luck. I did place the sub in my "master" seat and walked around the room while listening to the club scene from Blade and the place where i have it now (where it was calibrated) seemed to be the best sounding spot.

    Well, sorry for the lengthy post, but im trying to get this figured out. Any commenst, suggestions, or critcism is welcomed. Thanks!!

    Jason
     
  2. John Garcia

    John Garcia Executive Producer

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    Yes, that room is a bit large for the PB-10, but the real problem may be concrete since it is in the basement.
     
  3. Robb Roy

    Robb Roy Supporting Actor

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  4. Jay_Via

    Jay_Via Stunt Coordinator

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    Thanks for the replies guys. I cant believe i forgot to address what both of your posts talk about.

    John - Two walls are concrete with wood paneling over them, no insulation between the paneling and concrete, so i can see your point there. How much of a difference will this make?

    Robb - I had already been to your page and looked over it, however, i went back and double checked just to make sure.

    I just watched several scenes in LoTR - Return of the King and was able to get some excellent bass response in the Oliphant battle scene as well as the Ring Destruction scenes.

    Maybe im looking at this the wrong way .... as i understand it, the bass in the LoTR scenes i described is supposed to be deep and strong, and my PB10 replicates that. However, in other movies, if the bass isnt extremely strong in the soundtrack on purpose, it is possible to increase the feeling of that bass by choosing the right equipment (ie, sub and amp)??

    Hope that made sense. Thanks again everyone!
     
  5. John Garcia

    John Garcia Executive Producer

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    Concrete can make a very big difference, especially if the sub is marginal for the room size. Room modes could be an issue also, as you room is very close to 2:1. 1:1 and 2:1 can create poor response. I'd probably run a curve and see what your response looks like, because it may be a specific band or two, or you could have a huge dip in a key area. I had the PB-10 in my 19x20 room with high vaulted ceilings and it did respectably, but wasn't quite up to the task. SVS recommended adding a second one [​IMG]
     
  6. Jay_Via

    Jay_Via Stunt Coordinator

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    'Preciate the post john, but i have no idea what "run a curve" means, lol. Can you give me further info on that?

    Currently im thinking of putting the PB10 back upstairs and running a 2 x 15" driver infinite baffle.
     
  7. John Garcia

    John Garcia Executive Producer

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    Download some ranged tones from the web like http://bfdguide.ws/ , burn them to a CD, play them and take readings with an SPL meter. This will give you a response curve of what is happening in your room and show what frequencies you may have issues with.

    I currently run a single 15" Adire DIY in my room and I am very pleased with it. I get some serious output from that guy. IB is another worthwhile thing to look at.
     
  8. frogpond

    frogpond Stunt Coordinator

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    While this may be the case or not I did notice you said you get excellent bass from LOtR. I find this to be a common problem. People go out buy a sub, watch LOtR, Incredibles, Jurassic Park etc, etc. and go that was awsome! Now how come I don't get the same bass here and here? Then they try and crank it any which way possible. Background bass is just that background. It was meant to be that and mixed that way. Yes room size, construction and sub placement can play a large part but all too often I think people think its going to be a constant 'boom'.
     
  9. timZa

    timZa Stunt Coordinator

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    You have a point. when i dropped over $1k on a sub i want to hear it ALL the time. im coming to terms with there is only a few minutes of good bass in movies a few hours long.
     
  10. frogpond

    frogpond Stunt Coordinator

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    I have been in the television, film and viseo business for 13 years. One thing about movies is that the sound is mixed for optimum effect for the theater. This means the deepest bass around 10-14hz and then on up from there. Movie goers are supposed to get the bang for the buck. So when you talk about mid bass, there is plenty of it in movies but explosions, thumps and other sound fx are mixed down low on purpose. Gone are the days (pre mid 80's) where everything had to be mixed at mid levels now its full spectrum which is where SVS and others come in. With all the technology out there more and more speaker companies are aiming for that theater experience. Gone are when one speaker handled everything now its the sub handles 10hz-80hz(aprox.) and then you have your other speakers that handle everything else. Whether its the theater or the home this is why THX, Dolby Labs, and DTS all recommend what they recommend; example 80hz for crossover and other settings. The 'pop' of a gunshot is around 80-100hz and is better handled by the mids. Cranking your phase and other settings so the sub catches frequencies isn't right as the mid drivers in your other speakers should be getting this. Recommended settings and meter settings and letting the sub handle what its supposed to and calibrating the other speakers are there for a reason. If you do a breakdown in sound mixing in the opening beach landing scene of Saving Private Ryan you get everything from 20hz all the way up. This scene gives all the speakers and sub a good workout and should be seemless. Everything should not go 'boom' all the time. Now it could be a case where the speakers aren't giving you what you want.
     
  11. frogpond

    frogpond Stunt Coordinator

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