Does box rise change in relation to a change in power?

[may03LT]

Is box rise consistent?

Let's say you had 2 woofers and an amp rated at 2,000wrms @ 1ohm.

You clamp/meter the amp, do the math and find that your rise is 4 ohms @ 40hz.

Would the rise still be 4 ohms at 40hz if you were to double the power?

Hmmmmmm.....

[zayres29]

not only is box rise different the impedance of the woofers themselves change at different frequencies

[andym85]

not only power, but also frequency as stated above

which is why it shouldnt be considered for a daily driver...just strictly for burp setups imo...especially with crazy power..

[P4killer_]

Yea. Box rise only really matters on burp settups on music your rise, impedence and actual output is changing every second. So there's no real point on testing or setting gains for any one specifc frequency. In a daily application that is.

Now if say your amp.that does 3k lets say and you aren't as loud as you'd think you should be. Then you obviously check things like whether the amp.does.rated is the electrical up to par. Then after That box rise mght be a factor. if the enclosure build is a lil. Weak you could be getting hella rise nd that's why it isn't as loud.

But mostly only relavent in burp application

Edited May 23, 2010 by P4killer_

[bkolfo4]

I think you are mixed up on what "box rise" actually is.

To answer your question, yes impendance will increase with additional power due to increased heat and power compression.

[ISO]

To Meade,David,Roscoe,King suv,Ray, and Chode to just name a few of the people that can make the changes needed.

The thread that is pinned in the amplifier section were I explain a lot of stuff about how much actual power an amplifier makes was originally a thread about calculating box rise impedance and real world output and I think it needs to have its name changed to something that suites the thread better.

A title that has more explanation to it, but I can't think of a name to change it too so the average person would want to go check it out more often.

On a side note since technically it has turned into my thread, is there anyway I can take full control over it like the OP of a thread is capable of doing?

(EX: just to be able to make little adjustments here and there?)

How to calculate impedance rise, real world wattage and information on the 2 most basic forms of dash mounted bass knob controls.

The link: http://www.stevemeadedesigns.com/board/topic/23462-check-actual-ouput-of-an-amplifier/

[skittlesRgood]

this would have been very easy for you to have tested. put the volume half way up and burp it then do full tilt and see the difference in rise. its basically the same thing.

i very much disagree with everyone who says imp rise isnt important to daily systems. measuring imp rise and understanding it has gained me 5db and if i can continue to lower it i might get to 150db on music. this is all with the same box, same amps, same subs.

so ya dude, measure it, play with it, understand it. see how much power you can squeeze out of your amps.

[HHR Ed]

yes it will change with power.

And I also state that box rise is important to understand for daily setups and not just burp setups.

Yes it changes more when playing music, but you can still learn how to manipulate it to benefit a daily music playing box as well.

[may03LT]

not only is box rise different the impedance of the woofers themselves change at different frequencies

Gotcha, I only listed 40hz for simplicity.

The thread that is pinned in the amplifier section were I explain a lot of stuff about how much actual power an amplifier makes was originally a thread about calculating box rise impedance and real world output and I think it needs to have its name changed to something that suites the thread better.

A title that has more explanation to it, but I can't think of a name to change it too so the average person would want to go check it out more often.

Thanks man, I did check out that thread but didn't see a definite answer.

How bout "Everything you wanted to know about box rise but were afraid to ask"

this would have been very easy for you to have tested. put the volume half way up and burp it then do full tilt and see the difference in rise. its basically the same thing.

i very much disagree with everyone who says imp rise isnt important to daily systems. measuring imp rise and understanding it has gained me 5db and if i can continue to lower it i might get to 150db on music. this is all with the same box, same amps, same subs.

so ya dude, measure it, play with it, understand it. see how much power you can squeeze out of your amps.

Thanks man! I never quite thought of it that way. And yeah, this is for a daily setup. This whole idea started when a local guy did the math on his amp and found that he was only seeing roughly half of the rated power, far under the rms rating of the woofers. His solution was to get a more powerful amp. The amp would be rated at far more then woofers rating, however after rise the power to the woofers would be closer to the rms rating.

Also, 5db! That's very impressive.

yes it will change with power.

And I also state that box rise is important to understand for daily setups and not just burp setups.

Yes it changes more when playing music, but you can still learn how to manipulate it to benefit a daily music playing box as well.

From the man himself. Thanks for the info. I have some more searching/studying to do.

Thanks everyone for the replies.

[bkolfo4]

Why relate it to box rise? I bet if you doubled the power going to the sub in free air the impedance would rise. . .

The problem with impedance rise and music is that it is very possible to have certain frequencies that fall to or slightly below the nominal impedance. This could easily cause your amp to go into protect mode. Been there. . .

Edited May 23, 2010 by bkolfo4