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rockford build

32K views 152 replies 9 participants last post by  _Chicoblanco 
#1 · (Edited)
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.

equipment list
2 t2d4 12"
2 sets of t1 6x8 in the doors
pioneer hu
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

still needing
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.
 
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#2 ·
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.
 
#4 ·
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.
 
#5 ·
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.
 
#10 ·
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
 
#7 ·
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 .
 
#8 ·
Agree on aero ports (or octoports) you could also change tuning on the fly.

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
3 maybe
4 unnecessary
5 with double layers and 3 layer baffle(that you suggested) there would be 0 need for bracing....
 
#9 · (Edited)
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?

Folded horn?

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.
 
#11 ·
hmm. it really depends on all the rules of the class your competing in man. like if they dont allow you to have your car on than dont waste money on an alt. but than again your in alaska and who knows what goes on up there :p. i like the idea of aero ports because it allows you to change tunning from daily to spl on the fly. Also 45 degree corners on the box, kerfed ported and rounded port edges are my suggestions. Maybe re-enforce it with fiber glass but I have seen people actually loose numbers on the term lab. obivously deaden the [:)][:)][:)][:)] out of it. and do more runs of power and ground :p

I was thinking about competing but than I realised I dont have enough money to run something I would want to compete with that could be my daily driver. and the gas to get to all the places etc etc.


ohh and pass those rockford deals on to your fellow focus fanatics buddies?
 
#12 ·
well we can have the car on and rev the engine no limit on reving the engine but there is no need to go past 1800-2k rpm anyways. they put you in your class depending on total cone size im in amature 1, basicaly anything smaller then 2 12s or 1 15 up to 3 10 tens i think or 5 8s. im gonna round off all the edges to the port and do 45s in the corners of the port and more then likely 45s in the rest of the box as well. i sitll want to stay with a slot port i just like the sound better and i dont want to change out boxes just to compete. this build isnt just for comps its my daily setup that i listen to at about 80% volume 80% of the time and 100% volume 20% of the time.

i will add more power and ground wires as time goes by but i only have another $80 i can spend on the box.

i would be more then happy to share the rockford deals but i get it from a local shop through a freind and i have to jump through a few hoops every now and then helping my buddy out in order to get the deals.
 
#13 ·
aero ports will make it so you dont have the change the box, you just have to change the port thats why I was suggesting them lol. Like have 2 sets or ports 1 set will be your daily listening and the other set will be for spl but bassically you want to make the inside of the box as round as possible. Make it act like a little air cannon lol. Also if your firing into the hatch I suggest deadening it to the extreme. You probably want to make it as heavy as possible.
 
#14 ·
Ford bass , everything I mentioned can make a difference... If u want to milk every .1 db that's how ... Rounding corners allows for smoother air flow as does resining... I'd rather have a over braced box than a box that flexes . Alaskan , using the 2x4 is fine but it can effect air flow... Also remember to take into acct the displacement
 
#15 ·
^^ yeah the box is 4.04 after sub and the 2x4 i will round the 2x4 off to help make sure it doesnt mess with the airflow as much although if i can i wouldnt mind using some of that threaded pole you mentioned before so that i can make the box a little smaller so that i can fit everything in the hatch better.

the hatch door is done with a layer of dynamat and full of that expanding foam it took care of a lot of the rattles and flexing but it still moves the only real rattle from the hatch now is the wiper motor itself.
 
#16 ·
I would of done like 4 or 5 layers before filling it in with foam. Well not 4 or 5 but I would of done a good amount. I feel like if thats where you face the subs towards than thats where your biggest lost will be in pressure so you should over kill it there if possible. Yea ford bass has no idea what hes talking about. 02zetech is right making the corners round means less turbulance in the air.
I listened to 2 dc level 4 8s in a box that was no bigger than 4 12 packs put all next to each other with an aero port( all inside the box) tuned at 50hz the dude hit 144 all the way from 55-30hz.
he was only giving each of them 1500 watts.

He actually let me stick my hand in through the port to feel his box. The entire inside was circle and I mean the entire inside... It was all one solid piece of kerfed wood. he then went on the outside of it and put 4 pannels around it to make it appear square on the outside. but there was not a single 90 degree angle in the box and it was way to small for the requirments of the sub. it being that circular is what allowed him to get such a high number and flat response.
He also had 6 runs of power and 6 runs of ground. Going to an oldschool crunch ground pound 3000.1
 
#17 ·
well, im not doing more then 2 runs of power and 3 grounds just because of the cost and time it takes. i could put that much into deadening but on the other hand its my daily driver and i do plan on going turbo and doing some weekend drags so id rather not just to keep the weight down that much more.

and lets just all remember that ford bass says a 4k watt amp rms wont dim light if adjusted right on a stock elelctrical.
 
#18 ·
oh and just so everyone knows im willing to tune lower but no higher then 41hz i dont feel like lower would give me a higher score so it would be pointless for me to go lower then say 35hz
 
#19 ·
mitchv, yea i obviously don't know what i am talking about. I call Something that will give you .1db(if that) basically negligible, therefore i don't know what i am talking about. I would say to still do it for aesthetics but it's not like "oh maaaannn i gained MAJOR DEEEBEEZZ from rounded corners on my box".

It's so funny with the difference between audiophile forums, car audio forums and car specific forums(car audio section). Th knowledge base decreases and the bro science increases as you go down the line.
 
#20 ·
weither its .1 db or 3 db its still higher, if somthing as simple as rounded corners in side the box can give .1db and it adds a slight amount of strenght to the box then why not do it? when building a box you have plenty of scrap wood anyways. this is called fine tuning the setup, wich means to make those little changes that will make it that small amount louder.

if i wanted to gain another 3-10 db i would get a second amp and 2 more 12s. im looking to do better then a 145 in which i know i can with what i have, with the 1 12 i did a 143.9, people have seen as much as 3 db from doubling the cone which i did when i got my second 12. people have also seen as much as 3 db from an upgraded electrical in which i have a 250 amp alt that does rated at 1800-1900 rpm so there is another gian. now if i only gained 1db from the doubling total cone size and 1 db from the alt thats still put me at 145.9 then i round of the corners of the box and gain that .1 db that put me at 146db running 2 12s with 1880 watts rms according to the birthsheet for my amp. that would be where i want to be by the end of april. thats all low gains from the improvments im making to the last setup i could gain a whole 6 db from doubling cone size and the upgraded alt. i dont expect that much but i know i will do better then a 145 if i get to 147 from these changes ill be extremely happy with it but if by chance i gain that 6 db that would put me just below 150 but i dont think it will go any higher then a 146.5 to be honest.
 
#21 ·
Rounded cornerz in the inside of the box and on the port will be very benefitial.
just on the outside, like on the back of the box, would be virtually aesthetic only thats all im saying, id def do it.

Your only gonna run 1500 to each sub right? If you doublelayer each side an innerbrace is unnecesary.
That brace will most likely make you loose decibles and decrease efficiency. Your design is pretty rock solid with no need of a brace.
 
#23 ·
no im running a rf t1500.1bdcp birthsheet says just under 1900 watts rms x1 @ 1ohm at 14.4 volts. i will be running both speakers off the 1 amp so it will be closer to 950 watts each and im only doing a double baffle not doubling all sides. if i can keep it under 80 bucks to get my 1/o guage for my ho alt wood and some carpet/paint im gonna use the threaded pole like 02zetec suggested and change the box a little so that its still with in 3.98-4.02 cu ft after all displacements.
 
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