Just never happy

Discussion in 'Home Theater Projects' started by Dave_Gib, Nov 25, 2004.

  1. Dave_Gib

    Dave_Gib Stunt Coordinator

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    Hey,

    Offering this one up for ideas, I wanna hear your thoughts, and mostly the reasoning behind your suggestion.

    So, I got this living room, 13 X 16 X 8, it's a little small, but huge compared to what I am used too in an automobile.

    Anyway, enough with the background, I got a problem getting crisp bass, I didn't notice this until tonight, although I have had the suspicion for a while now. I played some music that I am used to hearing in my truck, when I noticed that the system in my truck kills this. Absolutely kills the subwoofer system in my house in every single aspect.

    I want the sub bass in my living room to sound like my truck, I have said that on here before and somebody told me to strap my TV to the hood of my truck, but I really wasn't kidding.

    Right now in my living room I have 4 12" Dayton Dvc subs in an 9.5 cu.ft. ported enclosure tuned in the mid teens.

    Dayton 12" DVC
    Qes - .373
    Qms - 6.7640
    Qts - .354
    Vas - 96.28L
    Sd - .0464m^2
    Bl - 13.11
    xmax - 16.4 mm one way



    My truck has 2 12" ED A series subs,(a TC sounds subwoofer with the Venezuela basket, graphite wooven flat pistoned 'cone')

    Qes - .45
    Qms - 4.71
    Qts - .41
    Vas - 47.27
    Sd - 0.0465 m^2
    re - 3.61
    mmd - 216g
    cms - 0.0002 m/N
    Bl - 17.49
    Xmax - 24.5 mm

    in a 3.7 cu.ft. ported box tuned to 24 Hz

    I want the living room to sound more like my truck, so my guess is to go with 4 more 12" Dayton DVC's and run 8 of them in a sealed enclosure.

    think back at me
     
  2. Travis_R

    Travis_R Stunt Coordinator

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    There are going to be some people on here that know alot more about this than me, I can however say that you are comparing 2 completely different accoustic atmospheres so to make the two sound the same I think is a tall order

    In your house you have four 12" subs producing the Bass in a room that is 1664 Cubic Feet

    Now I dont know the exact dimensions of your truck and even if I did its hard to figure cubic feet in a vehicle, assuming it is an extended cab my best guestimate is around 225 cubic feet and may be less than that

    Ok that said I would take these numbers and your numbers you listed above and try and come up with some formula even things out. ok theres my 2 cents
     
  3. Dustin B

    Dustin B Producer

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    Few questions. Is the living room completely enclosed around those dimensions or is it open to other areas? If so how big are those areas.

    Do you have an SPL meter? If so could you please use it to tell us what your nomral listening level in your truck is?

    I'll hazard a guess without this information though. My recommendation to get extremely powerful bass on a budget in that room would be to build 2-4 of these:

    http://www.adireaudio.com/TextPages/...eFrameText.htm

    Will lack a little in extension but for the vast majority of music they should allow the same sort of pounding your car gives.
     
  4. ColinM

    ColinM Cinematographer

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    Perhaps get a 1/3 or 1/6 tone disc and an spl meter, and measure the response in the truck.

    Then, get a 1/3 eq (or a parametric, if you want to) and try to emulate the same readings.

    At the same time, either seal the DVC's or re-tune to 25hz and add an infrasonic filter.

    You'll likely be around a q=1.0 or higher, with a hump in the bass band around 100hz-50hz.

    I did this, without the truck part, but I sealed my 90L and EQ'd for music by ear, then plotted. Wound up with a "house curve" and I deliberately chopped everything below 30. Works great, and I don't really miss the extension.

    Completely reversible.

    Good luck!
     
  5. KyleGS

    KyleGS Second Unit

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    A sealed Q of 0.8-0.9 would probably get you where you want to be. (prob. about 1cf each)


    I have a pair of the DVC 12's. I vented the box @ 5cf with three (3") flared ports. All open=25hz tuning (car like), 1 plugged (20hz tuning) and ~16hz with two plugs. I get the best of all worlds.

    Here's a link.

    When I first came into HT from car I went through the same thing. Eventually I came to like the "audiophile" sound vs. the thick chest pound of the car subs.
     
  6. Dave_Gib

    Dave_Gib Stunt Coordinator

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    well the living room is in the middle of the house, it connects the upstairs to the den, so yeah, there is alot of air there to be moved

    as far as normal listening levels in the truck, I'd say I keep it under 130 dBs most of the time, it'll do 150's below 30Hz on an AC mic, the best I ever did on a linX was 141 at a little over 25 Hz

    but I don't need my HT to be that loud at all, I just think it sounds too muddy

    as far as those horns go, I'd have to buy some 15's, any plans for some 12" horns?


    yeah, that's what I'm debating

    I had those same 4 12" DVC's in a ported enclosure tuned to 28 Hz in my last car, the SQ was awesome, but again this was in a car

    so I guess I am between tuning to 25 Hz, or going sealed, leaning more twords going sealed
     
  7. Patrick Sun

    Patrick Sun Studio Mogul

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    Good grief, value your hearing, ease off the volume knob.
     
  8. Dave_Gib

    Dave_Gib Stunt Coordinator

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    I really do, I just like the headroom
     
  9. Rory Buszka

    Rory Buszka Supporting Actor

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    I'd say go sealed. And DON'T skimp on the amplifier power. You should build a new enclosure, as well, so you can design it for the proper sealed Q. Take a look at Rod Elliott's (http://sound.westhost.com/) EAS subwoofer, which is functionally similar to the ELF principle used by Bag End Loudspeakers (http://www.bagend.com). It uses a special means of extending the response of subwoofer systems. But if you decide to use that, you'll have to assemble an electronics project. And you can't skimp on amplifier power.
     
  10. minhG

    minhG Stunt Coordinator

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    Dave,

    before you do anything, get a sound meter and measure the in room response (and the in car response) i think you'll be surprised at what the charts look like. i don't think i've ever seen an in-car plot that was close to being as flat as a home theater. you just get so much cabin loading in the car that you get a lot of peaks and valleys.

    which leads me to the next thing, most HT people will describe car bass as boomy and when you look at a typical plot that makes sense. when you're use to that and transition to a HT where the response is so flat it sounds weak.

    so you have to decide if your goal is a flat reponse or one with a little bump in the key frequencies for music and tune the subs accordingly. there is nothing wrong with adding a little bump in the frequency if that's what you want to hear.

    but before you can do anything, measure, measure, measure so you understand what changes you're making.


    btw, i have an ED8A and it 'feels' stronger then my vented Shiva, but when i measure the response it's up and down. and i also noticed that i have my sub levels in car much higher then i do for my mains, this doesn't work quite as well in your house--and it doesn't need to be higher since the noise floor is much lower in house anyway. and i don't think the E8A would shake the my apartment building like the Shiva.

    And the sound i'm after in car and in house is different, in my car the bass is in your face, you can tell when you it's 'on' since you have to get over the noise in the car. but in my house you can't tell the sub is working--until you turn it off and the bottom end completely drops out.

    sorry for the rambling, basically measure first, then come back with your questsions [​IMG]
     
  11. Travis_R

    Travis_R Stunt Coordinator

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    LOL, I really hope you dont live in an apartment... Dont get me wrong, I like a good system in a vehicle as much as anybody, but the punk neighbor kids that sit out front of their house for 5 mins at 2am rockin my house gets on my nerves..... probably the reason that it is Illegal to own an RPG cuz if I had one.......well you know
     
  12. Dave_Gib

    Dave_Gib Stunt Coordinator

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    the enclosure in the truck is tuned to the mid/low 20's, because in a small pickup you don't have as much cabin gain as you would in most other cars, I used my little 10" Dayton DVC in a sealed enclosure .707 alignment to find the cabin gain in the truck before I built the box, the response curve in the truck is pretty flat down into the low 20's, and I took away a little peak in the 35 Hz region with the head and the crossovers in the amp

    now I did the same in the house with my little 10", I think I'm pretty close although I haven't measured, it's not the response curve I'm worried with though, it's the lag

    I don't really notice it with movies, cause big explosions have a lag to them in real life anyway, but music makes the sub sound sloppy

    I'm guessing this lag comes from trying to move so much more air, and that I should go sealed to combat this as much as possible
     
  13. Jason Dalton

    Jason Dalton Stunt Coordinator

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    I could be wrong on this but I thought a small truck cabin would have more gain than most vehicles? Usually the smaller the space the more the gain.

    I'll have to agree minhG, measure whats going on in your truck and try to match it. As far as the bass being muddy, that could be a problem besides the sub, maybe some room issues. If you can, maybe try to bring your truck sub inside and see how that sounds.
     
  14. Ernest Rister

    Ernest Rister Producer

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    "I want the sub bass in my living room to sound like my truck, I have said that on here before and somebody told me to strap my TV to the hood of my truck."

    I'm sorry, but that's really funny.
     

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