Boon Posted June 1, 2009 Report Share Posted June 1, 2009 Box rise seems to be the latest buzz-word on here at the moment... lots of 'yeah go ahead and wire your subs under the rated impedance of your amps, box rise will keep it above so and such....' IMO using box rise applies to 1 thing and 1 thing only, SPL burps at a single frequency. This is the only time that it is both known and constant and hence can be relied upon to keep your amp safe from over-current damage. Box rise is NOT a constant. It changes massively depending on the frequency being played, it's all about the impedance/inductance curve of the woofer + enclosure combination. Moral of the story, don't assume box rise will protect your amplifier when playing music. And please, please don't tell people their amps will be fine below rated impedance 'because box rise will put you over 1 ohm' 10.x volts fo' life! Link to comment Share on other sites More sharing options...
Forevrbumpn Posted June 1, 2009 Report Share Posted June 1, 2009 well said Dr Boon I get tired of people asking me this, and resorting to BassBox6.0 for answers, and your 100% right about it being best for sine waves only I have a ritual called "terminator". I crouch in the shower in the "naked terminator" pose. With eyes closed I crouch for a minute and visualize either Arnie or the guy from the 2nd movie. I then start to hum the T2 theme. Slowly I rise to a standing position and open my eyes. It helps me get through my day. The only problem is if the shower curtain sticks to my terminator leg. It sorta ruins the fantasy. Link to comment Share on other sites More sharing options...
Noobtastic14 Posted June 1, 2009 Report Share Posted June 1, 2009 What about impedance drop? isn't the correct term impedance shift?? I'm sure preston can chime in about his amps and impedance Shift -Drew I am a United States Military Arts and Crafts Professional. Sand it off, Paint it on. uhoh_45 said: dont be a pussy P give the jeep to drew Link to comment Share on other sites More sharing options...
Forevrbumpn Posted June 1, 2009 Report Share Posted June 1, 2009 impedance is variable based on frequency, inductance of the coil, and airspace/ Q of the box What your talking about is similar, but not the same, Impedance rise is what fart boxers look for I just built a 12", and was testing it only 10 minutes ago, and at Fs (40hz) its impedance is 110ohms, yet at 1/2 Fs 20hz, its 3ohms and the peak, and dips come and go with phase/cycle rates, all that, but the post was just directed towards db drag, not intended to be used for bass race, which will kill amps, or subs I have a ritual called "terminator". I crouch in the shower in the "naked terminator" pose. With eyes closed I crouch for a minute and visualize either Arnie or the guy from the 2nd movie. I then start to hum the T2 theme. Slowly I rise to a standing position and open my eyes. It helps me get through my day. The only problem is if the shower curtain sticks to my terminator leg. It sorta ruins the fantasy. Link to comment Share on other sites More sharing options...
bkolfo4 Posted June 1, 2009 Report Share Posted June 1, 2009 Good post!!! Working impedance rise into the factor of voice coil and amp selection is more for experience users who know the equipment they are using and know when the limit is being pushed. If you have to ask the question about impedance rise and "will my amp be alright", the answer is more than likely already "no". . . Brian 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...
E a r t h Posted June 1, 2009 Report Share Posted June 1, 2009 i giggle a bit when boon posts these topics up because i feel the same way, i just never post it up like he does. although i know the intentions of this, im pretty sure most of the noobs will overlook this thread, or even question what it means still. either way... good post .... maybe helping that 1, will help a million Link to comment Share on other sites More sharing options...
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