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Billybravo's Guide to making a sub box

Discussion in 'A4/S4 forum(B5 Chassis)' started by imported_billybravo, Jun 14, 2005.

  1. imported_billybravo
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    imported_billybravo Guest

    Well you know me ppl i need my bass so i had to build a new sub box.

    The subs im using need 1.9cft of air space inside the box. You can work this out by using this method

    Length X Base X Height that worked out the area of the whole box then we divided this by 2 to get both enclosesures.

    We had to mess about for a bit on paper to get the right airspace and the right sized box for my boot.

    We also had B&Q do all the cuts we needed to make things alot easier and i got it all out of one sheet /ubbthreads/images/graemlins/smile.gif

    anyway heres some pics /ubbthreads/images/graemlins/smile.gif

    1. Get yourself some good mdf i used 18mm
    [​IMG]

    2. Get a mate to help you pre drill all the hole this makes it a lot easier to put all the parts togeather
    [​IMG]

    3. Because my box is so big we part built it outside then we had to build the rest inside the boot or it wouldn't of fitted in lol.
    [​IMG]

    4. Here you can see me using a mastik like no more nails to seal all gaps on the joints only do this when your happy its all going to fit
    [​IMG]

    5. Here im screwing the top to the box from behind as my seats dont fold down made things a little hard at times
    [​IMG]

    6. Here you can see me testing the fittment of the subs in the front panel make sure you cut the hole right or you might leak air out not good
    [​IMG]

    7. Front panel on when this was done i checked all joints and stuck even more mastik in them /ubbthreads/images/graemlins/smile.gif
    [​IMG]

    8. Job done and it sounds better in the audi than in the fez by far all is need to do now is make the false floor and trim it all
    [​IMG]

    _____________________________________________________

    False Floor.....

    1. check it out very easy to do i think the pic tells it all /ubbthreads/images/graemlins/smile.gif
    [​IMG]

    2. Check out the top panel looking good just need to trim it /ubbthreads/images/graemlins/laugh.gif
    [​IMG]
    www.top-end.com
    #1
  2. dummi
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    dummi smoking a6

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    f**k

    i thought mine was packed

    hope the boot is never ever needed in that car again /ubbthreads/images/graemlins/lol.gif

    very neat look

    i love lanzar

    what frequency are you getting from the boxes? what components you got there?
    #2
  3. imported_billybravo
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    imported_billybravo Guest

    im getting about 128 Db and thats been checked i cant remember the frequency of the subs but they go low


    and if funny you say you hope i never need to use my boot coz my rear seats dont go down and the box was so big because i had to get the right airspace so i made it in the boot.

    but i can still get to my wheel but i might not be able to get to the fuel pump /ubbthreads/images/graemlins/frown.gif

    not got any components as of yet i think the audi stuff is really good anyway so i might not get any.

    up fron im using a panasonic cq-hx2083n headunit very nice

    [​IMG]
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  4. docurley
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    docurley Moderator Staff Member Moderator

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    Nice J myman. lol
    #4
  5. imported_billybravo
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    imported_billybravo Guest

    lol yeah was.
    On my site it says billybravos stoned guide to making a sub box
    #5
  6. dummi
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    dummi smoking a6

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    kool

    i had that problem with my last car no fold down seats, still hard to get the spare wheel out in mine can just about manage it

    good work 128 db is good still need to measure mine.
    #6
  7. imported_billybravo
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    imported_billybravo Guest

    hi just a quick one does anybody know where i can get my hands on some cream leather, vinyl, leatherette

    ive been looking on the net for days now and ive emailed a few ppl but no really got anywhere yet and i really need to cover the install ready for VWNW

    any ideas /ubbthreads/images/graemlins/smile.gif
    #7
  8. imported_billybravo
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    imported_billybravo Guest

    Check it out ppl its all trimmed now /ubbthreads/images/graemlins/smile.gif and looking sweet as a nut

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    there is still a really big thing that is going to be fitted to the inside of the car in the next few months so keep your eyes peeled
    #8
  9. dummi
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    dummi smoking a6

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    looking good /ubbthreads/images/graemlins/ok.gif where you get the vinyl ? i'm looking for some for me other car
    #9
  10. imported_billybravo
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    imported_billybravo Guest

    some place in surry B&M Latex Sales

    took me a long time to find them and they are very cheep to and fast check there site out for more info



    www.bandmlatexupholstery.co.uk
    #10
  11. Markey
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    Markey Active Member

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    Looks great mate a cracking job...
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  12. dummi
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    dummi smoking a6

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    thanks mate looks awesome you'll definently get noticed with that any show, might see you at one
    #12
  13. imported_billybravo
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    imported_billybravo Guest

    well my site will be attending U.S.C at stanta pod on aug the 5th till the 7th with our own club stand and we will also be attending V.W.N.W in aug also

    check all info at www.top-end.com


    and thanks guys for your feed back

    i cant wait to fit the in car pc
    #13
  14. hop2407
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    hop2407 Active Member

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    Excellent website Billy...... /ubbthreads/images/graemlins/bravo.gif
    #14
  15. Dean_T
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    Dean_T Active Member

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    nice step-by-step /ubbthreads/images/graemlins/smile.gif

    the cap probably isnt doing you any favours though

    how did you measure the 128db, which mic/sensor was it on?

    seems quite low in all honesty if you are pushing 1kw into those subs?
    #15
  16. imported_billybravo
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    imported_billybravo Guest

    the car was tested at my works on a DB meter at spl they use this meter for health and safety because it can be loud at my works so they do checks once a month the 128 is a old figure which they tested on my old car but with the same stuff

    at the min the subs are only pushing around 500watts each as the amp isnt a mono block

    and i must ask you why you think the cap isnt doing anything as i know it is im not getting as much volt drop anymore when the bass line kicks in
    #16
  17. Dean_T
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    Dean_T Active Member

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    [ QUOTE ]
    and i must ask you why you think the cap isnt doing anything as i know it is im not getting as much volt drop anymore when the bass line kicks in

    [/ QUOTE ]

    is the cap is doing anything it will be detrimental to the system

    obviously a cap is meant to discharge itself when a heavy bass line hits, what happens if this bass line is a heavy/continuous one? your charging system will be put under strain to send power to the cap as well as the amp

    a bigger battery up front will be much better, as will be upgrading the 'big three' under the bonnet;

    alt to battery (+)
    battery to chassis (-)
    engine to chassis (-)

    or if you want to boom all day get a split charge system going with a second battery in the boot /ubbthreads/images/graemlins/smile.gif

    just to put it into perspective of how little power (and use) a cap is, they are generally 1farad, batteries (IIRC) are in the region of 1000 farads

    unfortunately caps are just a marketing gimmick, they just dont do what they say they do

    if they did you would be seeing all the loud competition guys using them /ubbthreads/images/graemlins/smile.gif
    #17
  18. imported_billybravo
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    imported_billybravo Guest

    ive got the biggist boch silver batt under bonnet i could fit im not really in to gel batts
    #18
  19. imported_VaulterTim
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    imported_VaulterTim Guest

    [ QUOTE ]
    [ QUOTE ]
    and i must ask you why you think the cap isnt doing anything as i know it is im not getting as much volt drop anymore when the bass line kicks in

    [/ QUOTE ]

    is the cap is doing anything it will be detrimental to the system

    obviously a cap is meant to discharge itself when a heavy bass line hits, what happens if this bass line is a heavy/continuous one? your charging system will be put under strain to send power to the cap as well as the amp

    a bigger battery up front will be much better, as will be upgrading the 'big three' under the bonnet;

    alt to battery (+)
    battery to chassis (-)
    engine to chassis (-)

    or if you want to boom all day get a split charge system going with a second battery in the boot /ubbthreads/images/graemlins/smile.gif

    just to put it into perspective of how little power (and use) a cap is, they are generally 1farad, batteries (IIRC) are in the region of 1000 farads

    unfortunately caps are just a marketing gimmick, they just dont do what they say they do

    if they did you would be seeing all the loud competition guys using them /ubbthreads/images/graemlins/smile.gif

    [/ QUOTE ]


    The one thing you forgot to mention is that you'll need a higher output alternator if the demand you're placing on the system is that great... if you don't you will fry it in no time flat with serious power!

    Simply replacing your power leads will actually make it easier to fry the alternator because the system has less of a problem carrying more current. This places a much higher demand on the alternator and unless it's spinning at very high engine speeds and is supercooled(!) it will fail sooner rather than later /ubbthreads/images/graemlins/frown.gif

    The split charging system you mention will use an uprated alternator to feed both sytems at once. A standard item (nor the battery) simply isn't up to the job...

    T
    #19
  20. Dean_T
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    Dean_T Active Member

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    [ QUOTE ]

    .....if you're pushing thousands of kilowatts...

    [/ QUOTE ]

    i think i was on another planet when i posted this, i meant a 'few' rather than a thousand /ubbthreads/images/graemlins/goofy.gif /ubbthreads/images/graemlins/blush.gif

    just had another look at the pics too, is that 8 guage cable you're running there mate? if so it may be best to upgrade to 4 guage or even 0 guage if you plan to go louder in the future!
    #20
  21. aaerica
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    aaerica New Member

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    Thicker cable helps prevent voltage drop over the distance of the cable run. The IASCA rule book has a guide to this which can be seen at http://www.talkaudio.co.uk/vbb/showthread.php?p=422094#post422094post422094
    The table represents the length in feet required to produce a voltage drop of 0.5 v at a given current draw. So if 100 amps are drawn through 4 awg cable a cable run of only 18 feet is required to produce this 0.5v drop.
    This drop may not sound like an awful lot but if you check the amps power outputs with the manufacturer specifically the difference between their rated power at 14.4v (car running) or 12v this drop will not seem as insignificant.

    As for "frying alternators" an amp doesnÂ’t work at its full capacity all of the time (unless you're talking about an SPL car) similarly the cars charging circuitry does not need to run at full capacity the battery will be more than capable of delivering many more amps that your amplifiers will need (look for info on batteries cranking amps etc).
    #21
  22. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    I think the guy has enough RMS power to handle running the amps at 13.9v instead of 14.4v. Do you honestly think the 3kw amp is going to be getting anywhere near max power that a 0.5v supply drop would actually have an effect?
    The standard alternator is designed to be sufficient to maintain the battery charge on the standard car with all the electrical accessories being used ) lights, heater, aircon etc. You add an additional current draw more than 3x that of the standard equipment I think it's gonna struggle. But I guess your headlights dimming in time to the beat is just an added bonus.
    #22
  23. Dean_T
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    Dean_T Active Member

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    [ QUOTE ]
    [ QUOTE ]
    if thats a proper kw (RMS not MAX) to each sub then you will NEED 0 guage

    4 guage is only good for around 90A over the length of a car mate, get it changed /ubbthreads/images/graemlins/smile.gif

    [/ QUOTE ]


    thanks mate at least someone can be grown up and talk some real tech

    [/ QUOTE ]

    i wouldnt crank it for long periods either or your amps going to go POP! /ubbthreads/images/graemlins/frown.gif

    with that kind of power you need to be careful, get the amp scoped for definite to make sure you arent clipping, this will pull a LOT more voltage than normal running and will fry your subs quite easily

    get a split charge too, your enemy with this much power is voltage drop - keep the volts high so your amp stays out of protection - best way to do this is 0 guage from front battery to boot with a 'big as you can fit' battery in the boot, battery close to amps = lower voltage drop, the 0 guage is there to make sure the high voltage from the alt doesnt drop over the length of the car

    make sure you get a split charge relay (caraudiodirect.co.uk sell them) otherwise if you run the front and rear battery permanently joined without a relay they will 'fight' against each other for charge and drain themselves leading to dead batteries /ubbthreads/images/graemlins/frown.gif

    hope that helps mate /ubbthreads/images/graemlins/smile.gif

    i must say though im running a sub with around 1kw with standard Audi fronts and they have real trouble keeping up, i plan to get some fibreglass kick builds made to house some DLS UP5s i have - cant wait to be honest as it sounds a bit too "bum, tish" at the moment /ubbthreads/images/graemlins/frown.gif /ubbthreads/images/graemlins/frown.gif
    #23

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