145db Examples

[robbythedude]

Yeah if you don't build for a specific class, you can get screwed in MECA.
I was in street 2 iirc for my Jimmy. Next highest score at the comps I went to was about 6db behind.

So, lets say I stuck with a single HDC4 15" w/ Q2200.1. The external amp rating is 200, so I should run an inline fuse @ 200 as well. Right?

Thus my score following their equation, ((200 Amps) x 10) + (176.71 Surface area of 15") = 2176.71. I am now confused on where I go with that score...

 

[LosIsATool 5,000+ posts]

You will run 1/0 cable. It's good for 300 amps so you will run a 300 amp fuse daily. If you need to drop the fuse to get into a certain class you could run it as low as a 35amp for burps but that takes testing to get the roll up just right.

 

[robbythedude]

Single 15" in a BIG box will get you there no problem at power level that you can run on your stock electrical. If you can run 2KW and want to invest in the upgraded electrical, set your sights to 147.

Almost everyone over-estimates how much box volume they have to work with. It is very important, particularly on low power, to have adequate box volume, large port area, and enough room to move the box around in the cargo area no optimize output. Often times you can find a full 2dB just by moving the box around in the cargo area to find the best position for the meter!

If I did the big three electrical upgrade, could I handle a 2KW on stock alt/batt?

Luckily, I am giving exactly what a SQ 15" HDC4 (or HDC3) sub wants. I can easily fit a 5cu.ft. box in my trunk. Box size should be no problem, but the design is where I fall short. Should I design the box with port facing into cab? facing ceiling? facing trunk door? facing side walls? Where should the sub be placed in consideration with the cab? More inside the cab? More towards the trunk door?

You will run 1/0 cable. It's good for 300 amps so you will run a 300 amp fuse daily. If you need to drop the fuse to get into a certain class you could run it as low as a 35amp for burps but that takes testing to get the roll up just right.

That last part went way over my head... Is a burp like a 30 second run? And what do you mean build up?

 

[csu87 10+ year member]

I'd do the hdc3 but I love those subs.

Might need another battery in the back with that power.

300amp fuse for daily. The smallest you can find and get to stay for comps. The cheap 20/30/40amp fuses on eBay are your best bet for comps. 2 20s on an aq3500 at .25ohm got me 151/152 if I rolled into it just right. Took practice but that's what you have to do for competing

 

[oxsign 5,000+ posts]

You've got an advantage with the hatchback. I did a 45 with 2 custom built 10"s and 1500 in a golf (same amp on 2 8"s did a 42 in same car). Did a 45 in my avalanche with 2 C2 15" and an AQ2200.

 

[LosIsATool 5,000+ posts]

Roll the volume up slow enough where it don't pop the fuse.

 

[robbythedude]

Roll the volume up slow enough where it don't pop the fuse.

Makes sense, okay lol Thank you

What happens if you blow a fuse while competing? Disqualified?

Edit: Should I design the box with port facing into cab? facing ceiling? facing trunk door? facing side walls? Where should the sub be placed in consideration with the cab? More inside the cab? More towards the trunk door?

 

[negolien]

My buddy has a t1500bdcp running two DC Level 4 12" Dual 1 Ohm Subwoofers and he hit a 143.2db at 41hz (TNE) in his first comp. Nothing special decently deadened trunk, standard ported box, big three and a D3400.

 

[hispls 5,000+ posts]

If I did the big three electrical upgrade, could I handle a 2KW on stock alt/batt?
Possibly, but why risk blowing up your amp? Go with a smaller amp or get a second battery.

Luckily, I am giving exactly what a SQ 15" HDC4 (or HDC3) sub wants. I can easily fit a 5cu.ft. box in my trunk. Box size should be no problem, but the design is where I fall short. Should I design the box with port facing into cab? facing ceiling? facing trunk door? facing side walls? Where should the sub be placed in consideration with the cab? More inside the cab? More towards the trunk door?

That last part went way over my head... Is a burp like a 30 second run? And what do you mean build up?

Again, I think you underestimate what 5 cube in a really solid box with a big arse port will displace, and to repeat, you will want plenty of wiggle room on all sides to move it around a little to find the sweet spot. Figure on 8 cube gross to get 5 cube net box.

"Burp" is 3 second tone. A 200A fuse is not going to protect that amp whatsoever, and I'm not sure what the rules allow, but more smaller fuses will be better for competing... for example, at auto-parts stores they sell a small fuse holder with a wire coming out of each side (for the fuses that go up under the dash of most cars... that style fuse). Get 10 of those and bundle all the wires together with solder, attatch one end to your power wire to the battery and the other end goes right into the amp, put a 5A fuse in each and bump up to 7.5A or 10A if you blow fuses often.

There's no ******* way you'll need 200A fusing on that amp with what you're doing and that will do absolutely nothing to protect the amp.

Makes sense, okay lol Thank you
What happens if you blow a fuse while competing? Disqualified?

Edit: Should I design the box with port facing into cab? facing ceiling? facing trunk door? facing side walls? Where should the sub be placed in consideration with the cab? More inside the cab? More towards the trunk door?

If you blow a fuse while playing you have no power to make your 3 second burp so you will have little or no score.

Sub up and port to the side is generally good in an SUV. If you plan the box build properly you can make things temporary enough to test different port and sub placements before you make things permanent.

 

[BoomTaco64]

if your looking for numbers, find the standing wave in the car and go from there.

 

[robbythedude]

Sub up and port to the side is generally good in an SUV. If you plan the box build properly you can make things temporary enough to test different port and sub placements before you make things permanent.

When you say side, you mean side of box? Or like pointing at the side-wall of the car?

In a competition application, are aero ports considered?

if your looking for numbers, find the standing wave in the car and go from there.

This went way over my head as well... Could you elaborate?

 

[will3 10+ year member]

Your fusing needs to be within 18" of the first amplifier in MECA , you can fuse whatever you would like @ the battery

You will be limited to a certain number of fuses in a class i.e. Street 2 =2 fuses not counting the fusing under the hood only the fuses within 18" of the amplifier

you can only run certain types of automotive fuses ANL, mini ANL, AGU

NO MAXi fuses

In street your enclosure and everything attached to it ( amplifiers,subwoofers ,etc.) must be below the seat line ( not the headrest but the actual seat) and in the cargo area ( behind the B pillar )

If you blow your fusing you will not be disqualified, if your score is over 120db it will stand, if it is not you should be offered a retry

there will be a learning curve for a few shows just try to build to the rule book and soak up what other seasoned competitors are doing and just be patient and enjoy yourself

 

[robbythedude]

Your fusing needs to be within 18" of the first amplifier in MECA , you can fuse whatever you would like @ the batteryYou will be limited to a certain number of fuses in a class i.e. Street 2 =2 fuses not counting the fusing under the hood only the fuses within 18" of the amplifier

you can only run certain types of automotive fuses ANL, mini ANL, AGU

NO MAXi fuses

So for example, I could just have a fuse @ the battery with 300amp rating for the 0awg wire then another fuse holder @ the amplifier that can be swapped during competition to a 25amp rating. That is legit?

Thank you for elaborating on specifications of the classes.

 

[BoomTaco64]

are you going to do a wall?

 

[robbythedude]

are you going to do a wall?

No way... I was going to build a huge box that would almost be like a wall to house 2x 15"s lmao

Now that I have talked to people here, I doubt it. If I can achieve 145db below seat line, I'd rather do that. Even at the cost of only doing 1x 15".