[quote name='adulbrich']"Rise" or "impedance rise" is a phenomenon that occurs with subs. When AC current passes through the coils, it creates an electromagnetic field. This interacts with the motor's permanent magnetic field and causes the soft parts to move. When the current is applied, impedance if the coils actually increase. This is due to heat, back EMF, and something else I forget. Enclosure also pays a role in impedance rise. As impedance rises, the subs see less power because the amp does not put out as much power.
Impedance is simply the term used for resistance in an AC electrical circuit.
The higher the motor force, the higher rise will be. Neo motors have much higher rise than ferrite structures because they are stronger.
@FML; on here had some crazy impedance rise, and wasn't seeing hardly any power out of his amp.[/QUOTE]
Yep, unavoidable with woofers. There was a huge argument on Facebook the other day, a guy claiming he had 0, absolutely no rise in his enclosure. Lol.
Im going on my 3rd run at a box for my DDs. And ended up buying another amp and tripling power just to get some output until i got a box dialed in.
As iv come to find out, many factors play a part when it comes to tuning, output, rise, etc.
For me, i bought brand new woofers. Been told until they are fully broken in (especially stiff suspension types like mine) , it can cause more then normal rise. Thst, and that they're dual 4's puts me in a spot where ill rise more. Even though im wired down, each voice coil is 4 ohms resistant, and i feel the more you have to wire down in impedance , the more it will want to jump back up to where it started. <<< that last bit is strictly theory. But then again. Theres no definitive science to it yet.
The other part of my battle is my vehicle, i drive an extended cab truck. Notoriously difficult to narrow down resonance and frequency peaks. But i didn't buy the vehicle with a big build in mind for once, its just turned into it once again haha.