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Get More Power Out of an Amp

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Victor Estrada:
Is it possible to get more power out of an amp by increasing the resistance (lower Ohms)?

For example:

Amp can do (per channel):
3850W RMS at 2 ohms
2400W RMS at 4 ohms
1330W RMS at 8 ohms

But the single speaker is rated at 2400W RMS 4800W Peak @ 8 Ohms

My goal is to push this sub to the max, but unfortunately, this amp does not support bridge mode

Tim McCulloch:
No.  The *total* amount of available current does not change, regardless of impedance.  Once it's at the end of the PSU capability there is nothing left.  Where do you think it would come from?  Garden fairies with unicorns delivering it?

Also, if you're thinking about adding a resistor in parallel to drop the impedance - where do you think that power will go?  HINT - you can warm your hands but not make more sound.

Keith Broughton:
First, one small correction...lowering Ohms is DECREASING resistance not increasing. That is why you see the power going up when the resistance goes down.
But, as Tim said, there is only a certain amount of power available based on the design of the amp and no Golden Fairies can help. ;-)

Given the power rating of the sub, it looks like your amp is a bit under powered to "take it to the limit"
There is a way to bridge the amp but it might not be something a novice should try.

Luke Geis:
There is a way to extract a little more, BUT....... it isn't practical and only works if you set your system up a certain way. And even after you employ the trick, it's only good for about 10-15% more, which is negligible.
 
How it's done:

1. Place amp in bridge mono mode.

2. Connect the leads of one speaker to the channel 1 side like normal.

3. Connect the leads from the other speaker to channel 2 in reverse. Negative goes to positive and vise versa. 

Now keep in mind 10-15% of 1,000 watts is only 100 - 150 watts. This will do absolutely nothing for you at all. It will not increase headroom and it will not increase SPL potential.

How it works is simple. When you switch the amp into bridge mono mode, all it does is swap the polarity of one of the power amp channels. This swap reduces the load on the power supply by an itsy bitsy bit and allows the dissipation of we bit more power. Not all amps will respond to this trick though. Switching mode PS, Class D amps are less likely to see any change at all because the PS is already so efficient and class D amps are so efficient. Basically, you can't squeeze any more out of it because it has already been extracted.

The long and short answer is NO you can't get any more than what the amp is rated for. Trying to run loads on the amp that are lower than the minimum impedance of the amp will cause it to overheat and burn up if ran too hard. If you need more SPL, you need either a bigger amp or a more efficient speaker.

The downsides to amp power:

1. It takes 2X the power to acquire a 3db increase in SPL from the speaker.

2. 2X the power is often cost prohibitive, or beyond the rating of the speaker you are powering.

3. More amplifier power is often not the answer if nothing else changes. You typically need a more efficient speaker, or more speakers period.

David Allred:

--- Quote from: Victor Estrada on December 20, 2018, 12:21:18 pm ---Is it possible to get more power out of an amp by increasing the resistance (lower Ohms)?

For example:

Amp can do (per channel):
3850W RMS at 2 ohms
2400W RMS at 4 ohms
1330W RMS at 8 ohms

But the single speaker is rated at 2400W RMS 4800W Peak @ 8 Ohms



My goal is to push this sub to the max, but unfortunately, this amp does not support bridge mode

--- End quote ---

What is the output of the speaker at 1300w?

You could run the amp heavily clipped.  Higher continuous output, but no higher peaks.  I'd rather have a speaker cruise than stress.  As you have it, that speaker is is practically fool proof, and catastrophe proof.
Or
Buy another amp and bridge them.

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