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Box rise is a b****


Gutta Trash

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Alright guys, so my boy Chauncy did a full tune for me, meter,clamps, scope, the works. I am currently running a AB Phantom 4k 2 15's wired to 1ohm. After all the tuning and testing my heart was broken. I'm doing a 145, BUT after box rise the amp is seeing 5.1 Ohms, meaning my subs are only seeing about 280 Watts each and are rated for 1100 each. Full potential not even close to being recognized, I have to change this. So I am going to piss everyone off and go with a Brazilian amplifier, this is where I need help. I would like to get an 8k but from what I've researched a 5k will get me real close to giving the subs full RMS power. I'm looking at the Stetsom 5k's there is a model that is 1 Ohm stable and 1 that is 2 Ohm stable. At 4 Ohms the 2 Ohm model actually makes more power, but would I have an issue with it only being 2 Ohm stable given that my subs are wired to 1. Will the amplifier actually ever see below 2 say at low volume etc..? Thanks in advance gents.

On 4/20/2010 at 10:06 PM, 'cc_audio' said:

Guys are just like girls, once you've had 18 inches you don't go back.

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All praise the one true God Term Lab. Good luck. I would try m9ving the box and stuff like that before buying gear. That's just me

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Wiring most brazilians below their minimum rated impedance is a bad idea. Some people will tell you with enough electrical you can cheat a little and wire a little below but I definitely wouldn't wire a 2 ohm brazilian to 1 ohm. No matter what you're always going to fight rise. I'd try a new box that's more efficient or do what strangeduck suggested before swapping amps.

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I would get a second amp like the one you have and run one on each sub.

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34 minutes ago, ShadeTreeMechanic said:

I would get a second amp like the one you have and run one on each sub.

can you show me math on  how that would help?

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I was thinking that two 4k amps at .5 ohm each would do something.

Edit: I guess it depends on what the coils are.

91 C350 Centurion conversion ( Four Door One Ton Bronco)

250A Alternator (Second Alternator Coming Soon)

G65 AGM Up Front  / Two G31 AGM in Back

Pioneer 80PRS

CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage

CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill

FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon)

Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon)

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I would never wire a brazilian amp below its nominal/minimal  impedance.

Work on your box, move it, try to play inverted, build another box, play with it...Before buying any equipment.

145 dB on 500 watts is a good score !

Sometimes a different style of wiring can help.

 

Good luck, you're on the right track !

 

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Use lag bolts to keep the box from rising 






Jk... Carry on

Thats cool. Im way too old to be upset by shit like that. Your name is winston. Your own parents hated you even before you were born.

My penis is bigger than your penis

I'm far from loud and my roof/headliner flaps around like Adam's ass on a windy day. I think it depends more on the structure of the vehicle.

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Just because you measured an "impedance rise" of ~5ohms doesn't mean that you are under-powering your subs throughout the whole music spectrum.

I assume your 145 score was just at one frequency?  Which just happens to be your peak.

Depending on your box, your impedance at other frequency's could be drastically different.

Here is an impedance sweep of my box, for reference:

My peak frequency is around 41-45Hz so you can see from the chart, my impedance there is similar to yours at about 5ohms or so.

But down towards my tuning frequency (32-33Hz) my impedance is much lower at 1.5ohms.  At other places its even more drastic.

So it wouldn't hurt to sweep your whole impedance to truly get an idea of what it looks like, not just at one frequency.

 

XL12 Inbox Door Closed Impedance.jpg

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25 minutes ago, Wicks said:

Just because you measured an "impedance rise" of ~5ohms doesn't mean that you are under-powering your subs throughout the whole music spectrum.

I assume your 145 score was just at one frequency?  Which just happens to be your peak.

Depending on your box, your impedance at other frequency's could be drastically different.

Here is an impedance sweep of my box, for reference:

My peak frequency is around 41-45Hz so you can see from the chart, my impedance there is similar to yours at about 5ohms or so.

But down towards my tuning frequency (32-33Hz) my impedance is much lower at 1.5ohms.  At other places its even more drastic.

So it wouldn't hurt to sweep your whole impedance to truly get an idea of what it looks like, not just at one frequency.

 

XL12 Inbox Door Closed Impedance.jpg

 

 

^^^^^^ This.

I was gonna say the same. Your not rising to 5 and staying there when playing music. That is where you took the one measurement. 

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