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SPL Gains!! Updates @page 30 (routing the port)

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Results so far!!

- Moving box around the trunk until i found the sweet spot: 0.5 dbs
- Changing box size until i found the best one: 2.2 dbs
- Removing sub´s boot: 0.1 dbs
- Negative wire run from battery to amp instead of grounding it to the car: 0.3 dbs
- 2 extra batteries: 0.2 dbs (depend on the application, i was using SMALL power).
- Printing Vinyl inside the box to make it smooth: 0.4 dbs
- PVC round over on the pressure point of the box: 0.2 dbs
- Extertnal flare on an aeroport: 0.9 dbs
- Internal flare on an aeroport: 0.7 dbs
- Duct taped old screws holes on the box: 0.3 dbs
- Sunvisors folded down: 0.5 dbs
- Moving front seats all the way forward: 0.7 dbs
- Taking out floor mats: 0.1 dbs
- Front seats vertically: 0.3 dbs
- Center console empty and open: 0.2 dbs
- Covering the sub´s pole vent hole: 0.14 dbs
- Duct tape around the sub: 0.25 dbs
- Using 8 gauge from sub to amp instead of a POS wire: 0.22 dbs
- Cooling the cabin with the a/a: 0.45 dbs
- Rounding the sub hole: 0.28 dbs
- Rounding the external edges of the box: 0.17 dbs
- Armor all the whole interior of the car: 0.06 dbs

- OFC vs CCA vs Welding vs electrical wires: 0.1 - 0.2 dbs difference only!!

- Grounding battery to chassis : 0.3 dbs

- Routing the mouth of the port : 0.15 dbs (only 1/2" , should be higher with a bigger jig")

- Raising tuning: 0.3 dbs, this depends entirely on the car!!
- Installing 45´s on non pressure points of the box: 0.4 dbs
- Steering wheel at lowest position: 0.2 dbs
- Having 2 round ports with different sizes: 0.5 dbs
- Printing vinyl outside the box: 0.3 dbs
- PVC roundover outside the box: 0.2 dbs
- Opening the glove box: 0.2 dbs
- Closing a/a vents: 0.5 dbs
- Inverting the sub´s polarity: 0.3 dbs
- Changing from PVC roundover to mdf 45´s : 0.2 dbs

Hey guys, just wanted to post a couple of things i tried this week, i had some 3/4" MDF in my garage and said, what the heck! I built a sealed box to show people how you can find the resonant frequency of a car:

After that, i started some nice trials and mostly errors haha, but here are some tips, advices, gains, scoring drops, etc etc , i started taking pictures but i got bored of taking them, this is my 99 Ford Explorer wich is a "big" SUV and i tried a very SMALL cone area for it, testing was at the beggining with one of my 2512´s but sub barely moved because of the small power i was using and the tiny little box, so i changed to a crossfire BMF 375 watts sub, i was using an Almani 1500 watts amplifier wich i don´think it´s even a 1000 watts amplifier, but who cares,once again, this topic is not meant for braking any world record, i don´t care if the number sucks, this topic is only to show you guys a few tips on how you can gain some debeezzzz!!!!

Said all that, let´s start with the box, i did it this way because i wanted to try 3 different box sizes with this thing, see how much i could raise or drop by getting it bigger, also ,remember that raising or shrinking the internal space changes the tuning frequency, so yes i had to retune this box each time i changed the internal space, i had A LOT of 4" pvc pipe in my garage so i didn´t care, this is the box:

Sealed box , 1.1 cubic feet after sub displacement:


Score with the sealed box:


After this, i drilled a hole for a single 4" PVC tube and got this box ported with an external port, this means that the box remained 1.1 cubic feet after sub displacement, i tuned this box to 42 hz


New score:

After this, i tried box positioning, and found out that this box scored WAY BETTER by facing the sub to the driver side and the port to the back!!
New score:

This score was at 55 hz, so i knew box was way to small and i needed to raise the internal space, to be able to do it, i didn´t glue the box so i could open the box a few times without any problems, anyways, i raised the internal space from 1.1 cubic feet to 1.3 cubic feet.

New score at 53 hz:
137o.png Edited by fecupe2001
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I always wanted to try taking out the boot of the sub, i saw a guy saying it raised his score 0.2 dbs , of course i wasn´t gonna pass the oportunity of trying this:



Next step was getting the box bigger, i raised the internal space from 1.3 cubic feet to 1.5 cubic feet with an external 4" PVC tube 12" long, this gave me around 39 hz, what i learned about this truck is that, no matter what you do, the thing likes to peak between 52 and 53 hz no matter where i tuned the box, of course the box was small so it was one of the reasons, here we go:


New score:


After this, i retuned my port from 39 hz to 42 hz trying to raise the tuning up for a better score, i was amazed of the result, honestly i thought i would raise a few tenths but i dropped to this:


So, i cut another piece of PVC and retuned to 39 hz again and my score got to 137.7 dbs again!!

The pictures about the scores END here, i honestly got bored of taking them, if you believe the scores nice, if not, then don´t bother to read the topic anymore :drinks:

Anyways, i changed the DD 2512 because the box was to small for it and the power was stupid small, so i installed a Crossfire BMF 12" wich is 375 watts, i raised 0.3 dbs by doing this, so, i went from 137.7 dbs to 138.0 dbs @ 53 hz.

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There are TONS of people on this forum wondering how much you can gain by running a negative wire from the front battery to the amplifier instead of grounding it to the car, so , i disconnected the ground from the amplifier to the car and connected one of my negative runs that comes from the front battery to see how much a single negative run add to this application, went from 138.0 dbs to 138.3 dbs!!

Then, i connected my 2 batteries on the back and the other pos and neg runs, so i went from a single batt with 1 pos and 1 neg to 3 batts with 2 pos and 2 neg, my score raised from 138.3 dbs to 138.5 dbs!!

So this means, that the 2 batts on the back were giving me 0.2 dbs on this application, if you are wondering why i got a small gain about having 3 batts instead of a single batt, it´s because this amplifier is so small that it doesn´t need too much power, In other words, going from a single battery without a negative run to the back , to 3 batts and 2 + and 2 - gives me 0.5 dbs on this application!!

Ok, i´ve ALWAYS wanted to try something different than the resin because it´s a pain in the ass to work with , and besides that, it´s expensive!!! Said that, we all know that the most of the time, you gain some by getting the surface of the box smooth as hell, since i have a printing supplies company, i took one my my PRINTING VINYLS and installed this thing inside of the box, if you guys wanna try this it´s way cheaper than the resin, also, i didn´t pay too much attention on details and ended up with a few scratches:




Looking thru the port:


New Score: :pardon:


As you can see, the dumb ideas sometimes WORK!! there aren´t bad or stupid ideas on SPL, you have to try everything that comes across your mind, you never know what´s gonna happen!!

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Taking the boot of the sub was pretty interesting.. And finally someone confirmed the ground haha!

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So far so good, we went from 134.6 dbs to 138.9 dbs on a single afternoon!!!

Anyways, it was time to move on to the 45´s , since i had A LOT of pvc, i prefered to try rounding the corners instead of building some wood 45´s , after this test i learned something IMPORTANT, this are the most crucial and dangerous things you can install inside of a box!!!!!!!!!!!!!!!!!

How come?? oh well, here are the pics:

I striped a 4" pvc tube on 4 pieces, first i installed some vertical round overs:




Guess what??? i went from 138.9 dbs to 138.6 dbs by installing those things =@

After the 0.3 dbs lost, i took them out to confirm my last score and got a 138.9 dbs again!!

So, the next step, was to install a single horizontal round over!!


New Score: 139.1 dbs

Then, i installed a second horizontal round over close to the port:


This one dropped my score to 138.7 , took it out and got to 139.1 dbs once again.

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Taking the boot of the sub was pretty interesting.. And finally someone confirmed the ground haha!

Yeah man, that helped a lot hehe, well, glad i could confirm something, tons of new updates in a few minutes!

This is awesome man keep it going. I've been trying to find time to do testing like this myself.

Thanks a lot hommie, yes sir there´s more coming up!!

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i like this thread already :drinks:

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