Hi
I got two 450 Watt speakers i want to use them with my computer.but i dont know how to use them.it got two connection.when i connected them to the computer it produced very low sound.do i need an amplifer?

 

Yes, of course you do!.

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PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

any one knows how to make an amplifer?

 

There are hundreds of designs on the internet, but first you need to decide what power you need? - it sounds unlikely the speakers are 450W (unless they are huge guitar or PA speakers?).

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

you dont mean 450 PMPO right? cause PMPO is not the real power rating...

 

Many little computer speakers are rated at thousands of PMPO Whats.
Their power supply can deliver only a couple of Watts.

My computer speakers have 3" drivers with pretty big magnets. The power supply is 12V/1A so the max output to each stereo speaker is about 3.5Watts RMS at low distortion. Or about 800 PMPO Whats.

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Uncle $crooge

 

If the magnet in each doesn't weigh over 10 pound/4.5Kg then it probably isn't 450Watt

 

I guess, the weight of the magnet doesn't mean anything for watts.Maybe the coil that has been wound to the diaphram could withstand huge amount of power which is rated to the RMS value. PMPO rating is just for the sake of creating illusion on their products.

 

The magnet weightis relate to wattage as the amount of wire is a fixed amount ie 8ohmsZ therefore you either have to increase the wire gauge to handle the current or increase the magnetic field. the option with the least impact on the moving mass, the cone, is the bigger magnet.

 

High power speakers use heavier wire for the voice coil, a heavier aluminum bobbin for the coil and a heavier cone. Therefore the mass is higher which requires a stronger (bigger) magnet to move it.

__________________
Uncle $crooge

 

what does PMPO stand for? pico ...something watts? : ) just kiding...i couldn't resist.. sorry

 

PMPO is a marketing farce that falsely represents the power rating of an amplifier or speaker. It means Peak Music Power Output.

Real power is measured with a sine-wave in continuous RMS watts at a low distortion at or slightly below clipping, over the entire 20Hz to 20kHz range of our hearing. The power rating of good speakers say the duration of the test. Some woofers can survive for hours. Tweeters are rated in milli-seconds.

The "peak" of the waveform has twice the amount of power. The peak-to-peak of the waveform has 4 times the power of RMS power.
"Music" sometimes has full power for only a moment before the power supply voltage sags or before the transistors overheat. The PMPO test measurement is for only a moment.
Usually the output is mesured with the volume turned up way too high so the distortion is also way too high, doubling the output power.
The resulting false power number is then multiplied by the squared age of your grandmother.

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Uncle $crooge

 

Then by 2, for stereo, or by however many channels the amp has.
My speaker are rated for 75W pink noise, constant. The magnets are somewhere in the region of 15lb/7kg each.