Different Impedances

[Tiger Bass 0]

This seems like such a simple question, but I can't find the answer.

What are the advantages and disadvantages between two different amps that put out the same out of power but at different resistances? Mainly looking for answers on a more technical level, like which will put less strain on my electrical system or which is thermally/mechanically better for the subwoofer.

I have a Fi SSD 10, D2 and copper coil, and I'm looking for a 1000w amp to power it.

[JimJ 11]

Technically, the damping factor changes, but for 99.9% of the solid state amps out there it's not audible...

Why are you running that much power to that sub? I'd be looking for an amp that does half that, personally...or get a Q instead.

[///M5 2,833]

In a sub amp it matters not, get the better bang for the buck. Personally I would have gone D4 for that reason though as there are more 2ohm budget choices than at 1 or 4. I will second Jim's statement though that you really don't need that much with that driver.

[Tiger Bass 0]

I'm looking for this much power with the possibility of upgrading to a Q or BL in the future in mind. I won't be running the SSD at full power though.

Edit: Also, any particular reason I should be looking to power my SSD at only about 500w? The Rms is 800w and my box is within the recommended Fi specifications.

Edited October 22, 2007 by Tiger Bass

[helotaxi 46]

Edit: Also, any particular reason I should be looking to power my SSD at only about 500w? The Rms is 800w and my box is within the recommended Fi specifications.

Because neither of those take mechanical limits into account. You can usually get pretty much all a sub has to give with less than RMS, and definitely get loud enough to damage your hearing.

[subwoofery 0]

I am also interested in knowing the main advantage of going with a 1000W@4ohm amp instead of a 1000W@2ohm.

Which will drain less current? and less strain on the electrical?

[eclipsepb25 0]

the one at 4 ohm puts less strain on your electrical system. and if you configure your wire for a 2 ohm load and use the amp that puts out 1000 @ 4 ohm, you'll actually be getting more then 1000 watts (taken its not under rated and the amp is 2 ohm stable) because there is less resistance. the one that puts out 1000 at 2 ohm probally puts somewhere around 700 watts at 4 ohm.

[helotaxi 46]

The amp that does the power at 4 ohms *should* draw less current, however if the amp design is optimized for that particular load, the difference shouldn't be that great.

[sqguy 0]

I read a whole deal the other day about how amps that run lower ohm loads are less efficient, but it didn't show any specific brand examples. It was more theory comparing 1-2 ohm amps to 4ohms amps (at their minimum load). I'm no electronics pro so...? It seemed pretty serious. Naturally if you run the same amp at 2 it will draw more power than running it at 4, if it can do both.

[Parker 2]

This seems like such a simple question, but I can't find the answer.

What are the advantages and disadvantages between two different amps that put out the same out of power but at different resistances? Mainly looking for answers on a more technical level, like which will put less strain on my electrical system or which is thermally/mechanically better for the subwoofer.

I have a Fi SSD 10, D2 and copper coil, and I'm looking for a 1000w amp to power it.

Volts X Amps = Watts. So if u have 2 amps 1 is rated at 1k watts @ 2 ohms and the other is rated 1k 4 ohms they'll both draw the same amount of current @ there rated load. What your looking for is efficiency. You just need to do some research on what amps are in your price range and how efficient ea amp is and go from there.

[helotaxi 46]

Volts X Amps = Watts. So if u have 2 amps 1 is rated at 1k watts @ 2 ohms and the other is rated 1k 4 ohms they'll both draw the same amount of current @ there rated load. What your looking for is efficiency. You just need to do some research on what amps are in your price range and how efficient ea amp is and go from there.

That same equation tells you that the amp running into the lower impedance will usually lose more power as heat and will usually be less efficient. Usually. You have to account for the on resistance of the output devices and the on resistance of the switching devices in the power supply. With a low enough resistance, the amp running into the lower load could be more efficient.

[sqguy 0]

Good point; class D amps. They take less power (per watts of output) compared to traditional ABs due to higher efficiency. If an amp is made to run X ohm load it should work best there. Most ratings I have read show a 4/2ohm amp being more efficient at 4ohms load but of course put out/use up more power at 2. I have not seen any tests of a 1 or 2ohm amp though, or at .5 ohm.