# How does box rise work?

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• 07-24-2012
shpatb
How does box rise work?
What causes box rise? Area of box? Sealed vs ported? How can a person calculate box rise? Right now I have two, 2 ohm subs, in compartmentalized box with about 1 cube each sealed, or other box compartmentalized with over 3 cube each ported for my subs. Just wondering what kind of ohm load my amp is actually seeing.
• 07-24-2012
Flex68
Re: How does box rise work?
Quote:

Originally Posted by shpatb
How can a person calculate box rise?

Copied and Pasted this into a file I saved....don't recall where it came from:

To calculate “box rise” you need an AC clamp meter and a DMM. You will need to measure the AC voltage output going to each of your subs (or if they're bridged just the wires going into the amp). Once you get the AC voltage you will need to find the AC current. You do this by clamping the negative wire going to the set of speakers.

Example:

You clamp your wire and get 38.6 amps of current
You probe the + & - wires and get 61.7 volts

Next you would take the 61.7 volts and multiply the 38.6 by it to find your MAX power which would be 2381 watts

Next to find out your impedence rise you would divide the voltage 61.7 by the amperage 38.6 which would be 1.59 ohms

So if you were to have a nominal or starting resistance of .5 ohms you would have a rise of 1.09 ohms, for an overall reactive load of 1.59 ohms.
• 07-24-2012
kushy_dreams
Re: How does box rise work?
there is no way to calculate it, only way to find out is to clamp your amp, its different at every frequency
• 07-24-2012
wickedwitt
Re: How does box rise work?
There is none if you bolt it down. :naughty:
• 07-24-2012
CAT MAN
Re: How does box rise work?
Quote:

Originally Posted by wickedwitt
There is none if you bolt it down. :naughty:

you saw that on caco also? lol....
• 07-24-2012
Flex68
Re: How does box rise work?
Quote:

Originally Posted by kushy_dreams
there is no way to calculate it, only way to find out is to clamp your amp, its different at every frequency

Technically you're correct, but if you play you standard/favorite genre of tunage and set the AC clamp meter to record the max via a "Hold" function, you're going to be able to get a pretty good idea of what your rise is....
• 07-24-2012
wickedwitt
Re: How does box rise work?
Quote:

Originally Posted by CAT MAN
you saw that on caco also? lol....

Yep, that was freaking hilarious.
• 07-24-2012
shpatb
Re: How does box rise work?
Do sealed boxes get more rise than ported? I think I'm going to go back to ported because the output from sealed is pretty poor, I mean they sound nicer and have the punch that I like but when I listen to rap it's just not the same... I'll try to borrow a clamp and DMM and see what happens.
• 07-24-2012
Fiendstolemyamp
Re: How does box rise work?
It's not something you need to worry about playing music.
• 07-24-2012
LBC
Re: How does box rise work?
Quote:

Originally Posted by Flex68
Technically you're correct, but if you play you standard/favorite genre of tunage and set the AC clamp meter to record the max via a "Hold" function, you're going to be able to get a pretty good idea of what your rise is....

No. He was dead-on correct. Your rise changes with every frequency. Sometimes there is no rise. There is impedence drop. Google: impedence curves for loudspeakers and you'll get a better understanding. You can't clamp 1 frequency and then assume you're rising that much on every other frequency. That isn't true. You rise the most at your port's peak frequency. That is going to be your loudest frequency also. This is all pretty simple stuff. There are just so many people out there spreading bad information it's kind of getting out of hand.
• 07-24-2012
Flex68
Re: How does box rise work?
Quote:

Originally Posted by LBC
No. He was dead-on correct. Your rise changes with every frequency. Sometimes there is no rise. There is impedence drop. Google: impedence curves for loudspeakers and you'll get a better understanding. You can't clamp 1 frequency and then assume you're rising that much on every other frequency. That isn't true. You rise the most at your port's peak frequency. That is going to be your loudest frequency also. This is all pretty simple stuff. There are just so many people out there spreading bad information it's kind of getting out of hand.

I've read enough of your idiocy on other threads to discount anything you say....especially since you apparently didn't even read the entirety of the one sentence I posted.

Go back to nuthugging cthedinger, and spreading more of your disinformation about how his product compares to others in the industry.
Anyone on here who has half a brain knows how irrelevant a little lamb you are, lol.
• 07-24-2012
LBC
Re: How does box rise work?
Quote:

Originally Posted by Flex68
I've read enough of your idiocy on other threads to discount anything you say....especially since you apparently didn't even read the entirety of the one sentence I posted.

Go back to nuthugging cthedinger, and spreading more of your disinformation about how his product compares to others in the industry.
Anyone on here who has half a brain knows how irrelevant a little lamb you are, lol.

What are you talking about? All you have to do is look it up. I'm not going to come in here and lie... and I wasn't attacking you. You're just not correct and I attempted to properly inform you. Calm down.
• 07-24-2012
Falcons
Re: How does box rise work?
Ish just got real.
• 07-24-2012
Flex68
Re: How does box rise work?
Quote:

Originally Posted by LBC
What are you talking about? All you have to do is look it up. I'm not going to come in here and lie... and I wasn't attacking you. You're just not correct and I attempted to properly inform you. Calm down.

As usual, you wish to bandy semantics.
You are trying to correct something that did not need correcting.

Quote:

Originally Posted by Flex68
Technically you're correct, but if you play you standard/favorite genre of tunage and set the AC clamp meter to record the max via a "Hold" function, you're going to be able to get a pretty good idea of what your rise is....

Both you and kushy are technically correct that the varying freq's in music will not allow one to pinpoint a single, accurate impedance to be able to say, "I have a xx.xx box rise."
However, if one follows the very basic guideline I posted, and play one's favorite "style" of music, then one can at least get a general idea of what to expect in terms of box rise, which allows one to account for something rather than nothing.

Your statements are kind of like someone saying they would rather know zilch if they can't know it all; its gotta be black or white, fukk all that gray; etc, etc.

So, again, I say to you, P!ss off
• 07-24-2012
LBC
Re: How does box rise work?
Quote:

Originally Posted by Flex68
As usual, you wish to bandy semantics.
You are trying to correct something that did not need correcting.

Both you and kushy are technically correct that the varying freq's in music will not allow one to pinpoint a single, accurate impedance to be able to say, "I have a xx.xx box rise."
However, if one follows the very basic guideline I posted, and play one's favorite "style" of music, then one can at least get a general idea of what to expect in terms of box rise, which allows one to account for something rather than nothing.

Your statements are kind of like someone saying they would rather know zilch if they can't know it all; its gotta be black or white, fukk all that gray; etc, etc.

So, again, I say to you, P!ss off

Ok, I'm glad you clarified. Your posts prove that you know nothing. The clamp results need voltage and current. You assume you can just look at the peak current and know something. You can't. That doesn't make sense. Nobody would know you aren't smart if you'd stop talking so much.
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