Ohms to Box Rise Question

[Grimmjoww]

Searched Google on this, and went through the forums here. Trying to just get a straight answer as it's debated. If you have a 1 ohm stable amp like a JP23, Cab or Tar is it sound to use a dual 1 ohm sub and wire down to .05 ohms? If I'm thinking correctly box rise should bring it back up over 1 ohm pretty quickly. I know a lot of guys will just buy a 3k amp for a 1.5k sub and go that route as well. Thanks

 

[hispls]

What exactly are you trying to accomplish here besides seeing if you can blow up your amplifier?

 

[Grimmjoww]

What exactly are you trying to accomplish here besides seeing if you can blow up your amplifier?

I was trying to keep impedance as low as possible to combat impedance rise if that was possible. Not trying to blow any amps up.

 

[Jimi77]

Impedance rise doesn't blow up amps. Low/too low loads or clipping blows up amps. Generally bass heads use impedance rise to their advantage rather than try to combat it.

 

[some dude]

Are you trying to save money?
What about buying a powerful amp?
Watts per dollar are very cheap these days.

Do you own amp & sub already?

 

[Grimmjoww]

Are you trying to save money?
What about buying a powerful amp?
Watts per dollar are very cheap these days.

Do you own amp & sub already?

Not trying to save money, was just asking if you could play for the impedance rise. When you actually start ripping on a 1ohm sub you can end up around 3-4-5 ohms. Why not start lower?

 

[Jimi77]

Not trying to save money, was just asking if you could play for the impedance rise. When you actually start ripping on a 1ohm sub you can end up around 3-4-5 ohms. Why not start lower?

Because starting lower risks blow the amp or tripping the protection circuit. For a daily, I don't see much reason to try and "cheat" with a lower impedance. However, as long as the system is properly designed and you stay at/above the amp's rated impedance, then there shouldn't be a problem.

 

[Deiimos]

If it is for music, wiring to 0.5 is not advised. Impedance on music can vary quite a bit, and it isn’t worth the risk. If at certain frequencies / volume levels the amps sees the 0.5 ohm, which is very likely / possible, the amp will be trying to pass far more current than it was designed for, also may trigger the protection circuitry, or it should. If you were competing in SPL, at a specific frequency, you might be able to keep the impedance near a certain point. With music, just don’t do it if you want your amp to last.

 

[Grimmjoww]

Cool thanks for the run down Jimi and Deiimos. I was honestly interested if there were adverse affects of this. Point taken, just learning the do's and dont's lol. You read stuff all over the web and then come here to get the shake down.

 

[hispls]

When you actually start ripping on a 1ohm sub you can end up around 3-4-5 ohms AT SOME FREQUENCIES. Why not start lower?

Emphasis added.

The answer is, because you can also see DCR at other frequencies and because low impedance is extremely torturous on semiconductors. Power is cheap and almost no competition org will give you an advantage using "cheater" amps anymore.

Here is a measured graph of the impedance curve of the wall in my Jeep wired to 0.7 ohm. Ratio of Z-max to Z-min to DCR and the amplitude will change but a ported enclosure will always be similar shape with at least two points being possibly extremely close to DCR. If you really care you will need to build the box, install it, then measure impedance.

@some dude is right IMO, power is cheap and comes in small packages, there's almost no reason to worry about this sort of thing these days.