for anyone that doesnt know i do spl contests and this will be my 3rd summer competing and only my 4th year doing car audio. i get a great deal on rockford gear and it has great sound quality while still getting loud and low. this setup is for daily listening and competing, once i get my new box built and the alt installed with big 3 all i will have left is a few changes to my front sound stage that will include some fiberglassing the front doors to add a 6" mid speaker tweeter and crossover all right on the door and then an amp to power the front and rear door speakers. then sound deadening the rest of the car.
for this 3rd year i am taking everything ive learned from the past 2 years of competing and putting it to use.
2 t2d4 12"
2 sets of t1 6x8 in the doors
rockford 1/0gauge 4gauge and 8 gauge
rockford 10 farad cap and interstate deep cycle rv battery
250amp micheal singer alt < just came in, installing on the 7th or 8th of april.
t1500.1bdcp for subs
t2 6.5 componet set
t400.4 maybe bigger
fiberglassing skills < dont know where to buy that at
speaker wire for when i get my mid amp.
wood for sub enclosure
with out any more delay some pics
the box will be 4 cu ft after displacement with a port area of 15.55in per cu ft tuned at 39 hz with a double baffle
best pic i have of hu right now, its a pioneer dont remember model number
pic of the one of the 12s im using in a box i was using it in. it was my first box build so be nice.
I have a single run of 1/0 gauge going from front the second battery in the hatch, from second battery to my cap then 4 gauge from cap to amp. just got a few feet of 2gauge for free gonna see if it will fit in the amp if it will im gonna replace the 4 gauge from the cap the the amp.
That brace is kinda useless and double stacking the baffle would be better.
Plus if you are going to compete in spl comps, 60hz tuning frequency would make a mucchchhhhhhh higher number on a termlab. I would take a guess that you would be ~155db @65hz as opposed to ~145db at 42hz.
And a tuning freq of 28hz with your enclosure in the right orientation would give you a range of 25hz-80hz as opposed to falling off from 40hz down and only playing with authority down to 35hz.
I am just trying to help, Build a SPL box and a box for Daily use and music. Swap for comps.
well actually, you said they have you play a bass cd to compete with....
Do they measure the peak spl?
What is the range of the bass frequencies on the cd?
the bass cd starts at 20hz i think and goes all the way up to like 80-90hz. id rather do a 145 at 42 hz then a 155 at 65hz.
i decided to go with a 39hz tuning on the box because my last box was tuned at 41 hz with 1.99 cu ft after displacement and i did a 143.9 with the 1 12 playing track number 47 in wich i beleive is 45 hz im still looking for the case to the copy i bought so i can double check that. it was even with the box tuned at 41 hz it would still hit hard loud and clean for daily listening and you could realy feel the lows.
the brace is there more for the back wall then the front it will most likely end up facing back so i wanted the back wall to have some extra support. i am doing a double baffle just didnt add it to the sketch up. the subs weigh in at almost 60 lbs a peice so i want to make sure the box can handle the weight and abuse from the subs
this is only my second box build so im still open to suggestion i wont be able to start working on it till the end of april so i have time to change things up a little bit.
their meter isnt a termlab either but ive been told it only .5-2 db higher then the termlab would meter it at and i dont know the brand or make of the meter they use right off hand its been a lil while since i was asked anything about the meter that is used. and the first box i built only had about 9 sq in per cu ft of port, i made it before i knew anything about actually designing a box. i actualy used the measurements and everything that came in the manual for the box. i was told shortly after building that box that the port area being so small could easily make it meter lower.
well whoever nets a higher spl score wins right?
so that's why i suggested having two boxes. Win the comp, swap boxes and have amazing bass for everyday.
First off do not Build a 60hz "spl " box ... it wont necessarily be louder ... Tune to where your box peaks at the Fs of the Focus . Your going to want to run Aeroports not a slot due to better efficiency ... Look at Terry Brocks build . A bonus with Aeros is that you can make them interchangeable . ...
BOX TIPS :
1 round all corners on the outside of the enclosure
2 Resin the inside of the enclosure and outside
3 do double layer 3/4" birch or mdf
4 front baffle 3 layers
5 use 1/2" all thread as your bracing .
How do people hit 150db with a single 8" and 500 watts... oh yea cus they tune the box to very high frequencies.
use this (http://www.linearteam.dk/default.aspx?pageid=newdriver) and it will give you an idea of the possible outcome with different tuning options.
Also you can have an enclosure that sounds loud and registers a low score and have an enclosure that isn't to loud but registers a very high score.
amplitude and energy are two different things.
1 Won't make even a minor difference but will look better
2 another thing that won't do much
5 with double layers and 3 layer baffle(that you suggested) there would be 0 need for bracing....
Do you need room in the car for the kids, etc.?
Have you played around with box position? Up-firing rear-firing etc.?
Have you looked into T Line enclosures?
Look into Decware's designs here, http://www.decware.com/newsite/caraudio.html
and let me know what you think.
This is a gift to the site.
they do 3 rounds in the 3rd round the second place holder and 1st place holder go head to head who ever does best there wins.
i am going to atleast round all the corners to the port, im doing a slot port because i love the way they sound. i know that with a box tuning of 41hz and just 1 t2 12 off the same t1500.1bdcp does a 143.9 port and sub facing back and a 142.xx sub and port up, and less when facing foward. im using 2x4 for bracing because i know it works and i already have it laying around so it wont cost me a thing for that.
i want to make sure the box stays in the back and that the hatch cover and everything fits and closes up good. im even gonna try to make sure the battery amp and cap all stay hidden away in the trunk. i will spend a day facing the box in different directions and then metering it everytime i move it. once i find the right direction for this box/setup im gonna move foward and backward side to side to see if it makes a difference. even gonna do it with the seats up and down, lots of testing on box placement before the first comp
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