may03LT Posted May 23, 2010 Report Share Posted May 23, 2010 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..... Quote Link to comment Share on other sites More sharing options...
zayres29 Posted May 23, 2010 Report Share Posted May 23, 2010 not only is box rise different the impedance of the woofers themselves change at different frequencies Quote Btw that was the first person. Ever banned by me while dropping a deuce. Feel privileged Link to comment Share on other sites More sharing options...
andym85 Posted May 23, 2010 Report Share Posted May 23, 2010 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.. Quote i likes me some audio stuff... Link to comment Share on other sites More sharing options...
P4killer_ Posted May 23, 2010 Report Share Posted May 23, 2010 (edited) 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_ Quote Setup: 2010 Hyundai Elantra Factory Unit via 4 chan NVX LOC Excessive Amperage "H/O" Alt Xs D3400/ Xs XP3000 Big 3. 2 Runs of +, 2 Runs of - DD M3b and 2 12" AQ HDC4s Link to comment Share on other sites More sharing options...
bkolfo4 Posted May 23, 2010 Report Share Posted May 23, 2010 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. Quote Current system: 1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s Previous systems: 2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz. 1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz. Link to comment Share on other sites More sharing options...
ISO Posted May 23, 2010 Report Share Posted May 23, 2010 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/ Quote Isobaric - Refers to the practice of coupling two drivers together to make them act as one. "Giving up doesn't always mean you are weak; sometimes it means that you are strong enough to let go." Insanity: doing the same thing over and over again and expecting different results. The Destruction of a person builds character. Link to comment Share on other sites More sharing options...
skittlesRgood Posted May 23, 2010 Report Share Posted May 23, 2010 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. Quote If I answered you in a well mannered, informative way, you asked a good question or had a good attitude. If I was an asshole, you asked a stupid question or you had a fucktard attitude... or I was in a bad mood. Team BassickHU: Pioneer AVIC Z110Front: Peerless SLS 6.5", Peerless HDS 4", Rainbow tweeter - running activeAmp: JL HD600/4 and DC 4 channel (bridged to midbass)Processor: JBL MS-8Subs: 2x 12" AA MayhemsAmp: DC 3kElectrical: DC power 270xp alt. 1/0 big 4. XSpower D3400 and six D680s. http://www.stevemeadedesigns.com/board/topic/121795-29-update-the-buick-is-getting-a-rebuild/ Top career scores: DBdrag 151.7 MECA SQ 82.25My SOTM build Yeah. im pretty sure they dont warranty retarded people. Link to comment Share on other sites More sharing options...
HHR Ed Posted May 23, 2010 Report Share Posted May 23, 2010 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. Quote Ed Lester ShowtimeSPL Host Showtime Electronics Video MarketingMy old Build Loghttp://www.stevemead...08/#entry511451http://www.youtube.com/showtimespl 5 time dB Drag Finalist Last ride 2007 HHR, current dB 153.5 and bass race 149.4 dB. 153.0 dB on music New Ride, 2008 HHR SS. Build under way. Loudest score ever = 171dB 2009 dB Drag Racing, North American Points Champion Link to comment Share on other sites More sharing options...
may03LT Posted May 23, 2010 Author Report Share Posted May 23, 2010 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. Quote Link to comment Share on other sites More sharing options...
bkolfo4 Posted May 23, 2010 Report Share Posted May 23, 2010 (edited) 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 Quote Current system: 1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s Previous systems: 2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz. 1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz. Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.