ohms vs watts
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=60781
Printed Date: July 03, 2025 at 5:39 PM
Topic: ohms vs watts
Posted By: coop513
Subject: ohms vs watts
Date Posted: August 05, 2005 at 5:35 PM
i have two 15" dual 4 ohm subs. is it better (for loudness) to run 450 watts bridged 4 ohms or 250 watts 1 ohm single channel? and if you know, please explain why more watts or less ohms is prefered.
Replies:
Posted By: stevdart
Date Posted: August 05, 2005 at 5:58 PM
The impedance (ohms, load) on an amplifier is what causes it to make power. A lower impedance will make the amp work harder and produce more watts....a higher impedance will cause the amp to work less and produce less watts. Read up on Ohm's Law. Loudness is watts...(along with the enclosure, the car, the damping, the speakers...). 450 watts is louder than 250 watts and it doesn't matter what impedance the amp is getting...watts are watts. You choose the loudness (watts) according to your overall system setup and your individual preferences. How you get those watts is determined by the coils configuration of the subs and the amplifier that is going to power them. Generally, subs are driven at a 2 ohm load into a mono amp...most output with least power input. But they can also be driven by a stereo (2-channel) amp at a higher 4 ohm impedance. The stereo amp will use more of your car's power to operate. And BTW, you're not going to achieve a 4 ohm load with two DVC 4's. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: slab42
Date Posted: August 05, 2005 at 6:32 PM
unless your amp is 1 ohm stable, don't run it at 1 ohm, I would either wire the sus together for a single 4 ohm load, and bridge the amp, or run the subs down to a 2 ohm load each, and wire them in stereo to the amp.
Posted By: coop513
Date Posted: August 05, 2005 at 6:40 PM
uhh i am pretty sure i can get a 4 ohm load on 2 dvc subs of 4 ohms each if i do this ---> Voice coils wired in series, speakers wired in parallel but any ways what you guys are sayin is one ohm is better because it also has more amps. thanks for your help
Posted By: Blowntweeters
Date Posted: August 05, 2005 at 6:48 PM
you can get a 4 ohm load out of 2 dual 4 ohm subs in a series parallel combo if you amp can run 1 ohm go for it the only thing that doesn't make sense is that the amp info you provided says that the amp will produce more power at 4 ohms then at 1 it should be the other way around
------------- 1974 ford pinto 4 15" punch Z power punch bd 1001 pioneer DEH-6700
Posted By: dwarren
Date Posted: August 05, 2005 at 6:51 PM
stevdart wake up!
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Posted By: kfr01
Date Posted: August 05, 2005 at 6:57 PM
stevdart wrote:
Loudness is watts
I agree with what stevdart said. Stevdart is the man. I do, however, take exception to the above quote. Loudness is the intensity of a sound as perceived by a human. SPL is a physical unit that represents the amplitude of a sound. Power driven through a speaker produces sound pressure. Power is represented by a unit called a watt. An increase in wattage directly correlates to an increase in SPL until any number of physical limits are approached. So, loudness is not watts. Watts help product SPL. SPL affects (perceived) "loudness." So, the more accurate statement would probably be: "Watts directly affect potential loudness, limited by everything else physical. " Hi. :-) ------------- New Project: 2003 Pathfinder
Posted By: stevdart
Date Posted: August 05, 2005 at 7:11 PM
Damn kfr01, that is exactly what I was trying to say but I couldn't put it into words! :) Where you been, boy? And I had too much higher math clouding my brain... ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: stevdart
Date Posted: August 05, 2005 at 7:25 PM
coop513 wrote:
but any ways what you guys are sayin is one ohm is better because it also has more amps.
Not what I said, anyway. Watts, not ohms, is the deciding factor for "perceived" loudness (okay, kfr01? ;). The ohms is just what the subs will wire to and what the amp does with that load. In fact, the lower the ohm load the worse the amplifier will perform. Look at this Ohm's Law formula: I X E = P Power in watts is the result of amps times voltage. Amps is the word we use for current. Voltage is not current. Voltage, when high, means that the amperage can be low to achieve the same watts output. When the voltage is low, the amperage has to be high to achieve that output. Amperage makes an amplifier work hard and run hot, and the result is that the specs deteriorate. So to answer your question more directly, NO...running at 1 ohm is not the best way to do it. But here's the problem...you have to become familiar first with the different types of amplifier classes and what impedances they can work with. This will not be achieved in this thread, I can assure you of that. kfr01, I meant Roy! ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: coop513
Date Posted: August 05, 2005 at 9:55 PM
yeah but a one ohm load produces more amps and amps is what pushes the watts so isnt it the lower ohms the harder it will hit??
Posted By: coop513
Date Posted: August 05, 2005 at 10:32 PM
hey blowntweeters thats because the 4 ohm load is bridged and the one ohm load is single
Posted By: DYohn
Date Posted: August 06, 2005 at 10:41 AM
One ohm load = amp works harder =amp draws more current = amp is closer to its limits at all times = amp is far more likely to clip = amp is far more likley to distort = amp makes more heat, noise and distortion = speaker voice coils are far more likely to overheat = much more likely to produce a crispy crittter system. Yes, if you have a one-ohm stable amplifier it will produce "more watts" and in general will force the speaker system to produce a few more db and you will make more noise. But unless you really know what you're doing and are very careful in your setup I recomend you operate any system at no less than 2 ohms, 4 to be safe. I also know of NO readily available multi-channel amplifier that can handle a one-ohm load when bridged. Most require 4-ohms minimum. ------------- Support the12volt.com
Posted By: jeffchilcott
Date Posted: August 06, 2005 at 10:48 AM
Hey, Dyohn the Kicker xs 100 is a multichannel amp. and it takes a 1 ohm mono load.. now its just the matter of traking one of these amps down and finding one for less then $3-400 haha Just had to give ya some grief.
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Posted By: DYohn
Date Posted: August 06, 2005 at 11:21 AM
Cool I didn't know that. Grief welcomed anytime! ------------- Support the12volt.com
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