Kyblack76 Posted October 27, 2014 Report Share Posted October 27, 2014 Also SLINKY calm your tits... jesus..... ??? I am the calm one. Good...... SMD SUPER SELLER The Burban Build Blazer Build sold Acura trunk build sold Link to comment Share on other sites More sharing options...
bkolfo4 Posted November 3, 2014 Report Share Posted November 3, 2014 Take your reactive impedance and subtract your nominal impedance from it and that is your box rise. Your nominal impedance is the load at the amp, for example let's say 1 ohm. You will need a clamp meter and a dmm to read voltage and amperage from the amp on a burp. So I will throw some hypothetical numbers out there to show how it is done. Let's say your amp is wired to 1 ohm nominal and on a 50hz burp you produce 117.6 volts and 42.4 amps. To find out what you are working with you will need to take 117.6 and divide it by 42.4, which will give you 2.77 ohms. The 2.77 ohms will be your reactive impedance. Next you will take 2.77 and subtract 1 ohm from it. This gives you 1.77 ohms, this is how much box rise you will have. This is the method that on how to do so explained to me by Mike Singer about 6 years ago and is how he told me he figured out box rise in his vehicle. If I'm not mistaken he was told this information from Team Neo Eric, so this is not my info as I will give them credit for showing me how to do so. I am glad you didn't make this up yourself, and I would advise you don't keep spreading this answer. Subs have an impedance curve with a peak at Fs even when they are not in a box. Putting the sub in a box does not cause the sub to go from being a flat "1 ohm" to some higher number. 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...
Nightshade Posted November 3, 2014 Report Share Posted November 3, 2014 Take your reactive impedance and subtract your nominal impedance from it and that is your box rise. Your nominal impedance is the load at the amp, for example let's say 1 ohm. You will need a clamp meter and a dmm to read voltage and amperage from the amp on a burp. So I will throw some hypothetical numbers out there to show how it is done. Let's say your amp is wired to 1 ohm nominal and on a 50hz burp you produce 117.6 volts and 42.4 amps. To find out what you are working with you will need to take 117.6 and divide it by 42.4, which will give you 2.77 ohms. The 2.77 ohms will be your reactive impedance. Next you will take 2.77 and subtract 1 ohm from it. This gives you 1.77 ohms, this is how much box rise you will have. This is the method that on how to do so explained to me by Mike Singer about 6 years ago and is how he told me he figured out box rise in his vehicle. If I'm not mistaken he was told this information from Team Neo Eric, so this is not my info as I will give them credit for showing me how to do so. I am glad you didn't make this up yourself, and I would advise you don't keep spreading this answer. Subs have an impedance curve with a peak at Fs even when they are not in a box. Putting the sub in a box does not cause the sub to go from being a flat "1 ohm" to some higher number. Yeah I have never been 100% sure about what the hell box or impedance rise even is. I do know that the math behind this method is correct, but what it exactly accomplishes is not that useful. I have read the info at this link before http://www.atrendusa.com/blog/impedence-rise-car-audio/ but still don't see the point of it. Like I said before though this is how a few competitors attempted to show me how to calculate box rise and the math works out, but the information isn't really that valuable unless you are seeing that you have a ton of rise and take action to add power to compensate for it, or make modifications to the enclosure to help keep the impedance down. 2013 VW Jetta GLI 2.0 Turbo 1 Sundown Audio SCV2000 1 Sundown Audio X15 V2 1 XS Power D3100 Audio Control LC6i Stock Deck 146.4 sealed on the dash at 37hz 2001 Focus ZX3: RETIRED Team Sundown Audio, Team XS Power, 2 time NSPL Car 3601-Up Champion, 2 time NSPL Car Hardcore ChampionHighest NSPL Scores to date:154.3db on the dash sealed at 46hz, 156.2db in the kick at 46hz155.2db unofficial on dash at 43hz Link to comment Share on other sites More sharing options...
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