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  1. #1
    Senior Member jarrods's Avatar
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    SPL advice required.

    Hi,

    I am building a new home that will have a dedicated Home Theatre room and I am now about to start working with suppliers to find a suitable wall/ceiling construction to minimise sound leakage to other rooms. I’d like to know the approximate SPL (dB) that my system could create in the room to get an idea of effectiveness of the walls (most quote a sound reduction in dB).

    The room will be 6000 x 4500 x 2250mm (20 x 15 x 7ft) with the following gear:
    MOSFET 180W per channel for JBL 4344 MF & HF (2122H, 2425J & 2405)
    Crown K1 350W per channel for JBL 4344 LF (2235H)
    Crown K2 800W per channel for pair of Sub1500
    MOSFET 110W per channel for JBL Control 5 (Rears)
    MOSFET 110W per channel for JBL Control 5 (Sides)

    I know it is near on impossible to calculate but I was wondering if anyone could give a rough approximation from personal experience.

    thanks,
    Jarrod

  2. #2
    Senior Member richluvsound's Avatar
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    Quote Originally Posted by jarrods View Post
    Hi,

    I am building a new home that will have a dedicated Home Theatre room and I am now about to start working with suppliers to find a suitable wall/ceiling construction to minimise sound leakage to other rooms. I’d like to know the approximate SPL (dB) that my system could create in the room to get an idea of effectiveness of the walls (most quote a sound reduction in dB).

    The room will be 6000 x 4500 x 2250mm (20 x 15 x 7ft) with the following gear:
    MOSFET 180W per channel for JBL 4344 MF & HF (2122H, 2425J & 2405)
    Crown K1 350W per channel for JBL 4344 LF (2235H)
    Crown K2 800W per channel for pair of Sub1500
    MOSFET 110W per channel for JBL Control 5 (Rears)
    MOSFET 110W per channel for JBL Control 5 (Sides)

    I know it is near on impossible to calculate but I was wondering if anyone could give a rough approximation from personal experience.

    thanks,
    Jarrod

    WHY BOTHER BUILDING A DEDICATED ROOM WITH A 7' CEILING ? Waste of money ..... Basement ? dig the another 3' out !

    Opinion based on experience !


    Rich

  3. #3
    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by richluvsound View Post
    WHY BOTHER BUILDING A DEDICATED ROOM WITH A 7' CEILING ?

    Rich
    Agreed - The best sounding room in our house has a cathedral ceiling ... give the sound somewhere to expand into!
    2ch - Oppo981, JoLida502, JBL L200+, KEF 105.4
    HT7- XDA-2, BDP93, 4b NRB, B&K 5ch amp, Vandy 3A, 2Ce, VCC1, TF600 & JBL 4641

  4. #4
    Administrator Robh3606's Avatar
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    Assuming a basement another option is to go up. You could add to the foundation perimiter height probably for less cost and add a couple of steps or just change the grading on the property using the fill from the hole. Depends on the water table the fill quality and drainage and what your engineer recommends if you want to add height there.

    As far as your question I have a room of similar size where my HT is set-up. I would just look at it as though the peak SPL will be at the speakers themselves and use those numbers to determine worst case SPL to see what the issolation will do. I assume you know how to calculate it.

    I can hit 120dB peaks in the low end on movies with a pair of B380's for LFE and a pair of LE-14's doing L+R as subs in a full range stack. It can get quite loud depending on the effects. Th biggest issue will be isolationg the LFE energy from the rest of the house. My first floor wood floors come alive. Quite a bit gets through them or re-radiated by them.


    This might help as well but remember it is a -3db loss for doubling distance not -6db when you are in a room.

    http://www.sengpielaudio.com/calculator-spl.htm


    http://www.sengpielaudio.com/Calculations03.htm

    Search around this sight lot's of info

    Have fun building it You lucky dog


    Rob
    "I could be arguing in my spare time"

  5. #5
    Senior Member richluvsound's Avatar
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    Hi Rob,

    first thought was to go up .... Cost , Planning . If the house is already designed , Its cheeper to dig deeper in the area desired .
    If planning has been approved , then one would need to redesign and re-submit the drawings -both costly and time wasting . especially if the contractor has a start date .
    If the concrete is properly damp-proofed ,the water table should not be an issue . Australia still has quality tradesmen ,unlike here Properly engineered basements are designed to float to some degree . Either way , a sump pump is not expensive !

    I don't wish to be too critical ,but one has the opportunity to do this, for the sake of a couple of grand ... 1 hr for the machine to remove the extra soil - generous ... and another $ 1500 for the extra concrete , why not go for it .

    Maybe Jarrod could give us bit more info ... A plan and elevation of the room would be a great help !

    Rich

  6. #6
    Administrator Robh3606's Avatar
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    first thought was to go up .... Cost , Planning . If the house is already designed , Its cheeper to dig deeper in the area desired .

    High Rich

    Wasn't sure a friend went up to get 10" celings in his basement. Where I am you can't go down. Water table is too high. Half way down the block the houses are on slabs. It's like that all over the island on the south shore. North shore is the high side so you can go as deep as you want. I am at 28ft up there it's well over 100ft many places over 200ft

    Either way it should be fun for him.

    Rob
    "I could be arguing in my spare time"

  7. #7
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    Quote Originally Posted by jarrods View Post
    Hi,

    I am building a new home that will have a dedicated Home Theatre room and I am now about to start working with suppliers to find a suitable wall/ceiling construction to minimise sound leakage to other rooms. I’d like to know the approximate SPL (dB) that my system could create in the room to get an idea of effectiveness of the walls (most quote a sound reduction in dB).

    The room will be 6000 x 4500 x 2250mm (20 x 15 x 7ft) with the following gear:
    MOSFET 180W per channel for JBL 4344 MF & HF (2122H, 2425J & 2405)
    Crown K1 350W per channel for JBL 4344 LF (2235H)
    Crown K2 800W per channel for pair of Sub1500
    MOSFET 110W per channel for JBL Control 5 (Rears)
    MOSFET 110W per channel for JBL Control 5 (Sides)

    I know it is near on impossible to calculate but I was wondering if anyone could give a rough approximation from personal experience.

    thanks,
    Jarrod

    Really, you don't need to know how loud it will play (it will play louder than you can stand to be in the room with) so you only need to know how loud you can stand it and design for that.

  8. #8
    Senior Member jarrods's Avatar
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    ceiling height

    Well new HT is nearly complete and it has a 2550mm (8ft 4") ceilings. It sounds much better than my previous lounge in my 2 level appartment that was 6m x 5m x 8.5m (30ft high at peak of cathedral ceiling). When I say much better I mean MUCH better.

    It is mostly underground and walls that do not face dirt have 2 layers soundstop plaster, insulated stud wall, airgap, another insulated stud wall and another 2 layers soundstop plaster. No idea of the total HT built cost but I can state the best value for money was the Vicoustic acoustic treatment panels. It is these panels I attribute the sound quality to and nothing to do with ceiling height.

    As for SPL... well at full volume you cannot be in the room; outside at the back of my house the noise level is minimal (like a car diving down the street some 40 meters away completely drowns out any HT noise).
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  9. #9
    Senior Member Lee in Montreal's Avatar
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    Hi Jarrod.

    Thanks for the follow-up. So. Did you dig up an extra 2 feet? If so. I think it was the wisest decision.

  10. #10
    Administrator Mr. Widget's Avatar
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    Looking really good! Congratulations!!

    I bet it does sound good.


    Widget

  11. #11
    Senior Member Ian Mackenzie's Avatar
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    I Jarrods,

    Looks good.

    I went through the same thoughts when had my new home built a couple of years ago

    For comparison had the house overall ceiling height increased to 2550 for about 7K and added a lamininated window for the rear HT room and inter wall/ceilng acoustic wadding for about 2 K.

    The interwall insulaltion at build makes quite a difference. Forunately and next door neighbours house has the dead side facing the HT room so its no big deal

    My TH amp is 170 watts (Pioneer), 800 watts for single 2245H sub. The round and the room is slightly smaller than yours and I find it plenty loud. No wall panels at this point

    The issue is really the bass and not higher frequencies.

    Send me a PM and we will catch up at some point

  12. #12
    Senior Member jarrods's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    Hi Jarrod.

    Thanks for the follow-up. So. Did you dig up an extra 2 feet? If so. I think it was the wisest decision.
    Actually the build was always planned at 2550mm for the whole lower level. I just made a typo in my first post (then converted what i wrote to feet which we never use here).

    jarrod

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