Basics of loud speakers

[Jaminator]

Hello folks,
I have some doubts and questions about the device speaker.

If a speaker is rated at 8 ohms 1000 watts rms it means the coil can take in huge curent an voltage to sustain that power.
The why are the voice coils of these speakers thin ranging less than 1 millimeter. Dont you think if they gonna take that current and voltage they shud be thicker as the power of the amp incrreases.

In one line why are the voice coils made up of thin wires though rated for high wattage.

[Ron E]

Ever think it can't actually handle the rated 1000W? Any "good" music will have a crest factor of 10-20 dB - meaning that a signal with 1000W unclipped peaks will use 50-100W RMS average. IF you try to get 1000W rms, your amp will be clipping the peaks and sounding like crap, but if you listen to modern popular music, you might not notice.

Realize that VC heating happens continuously along its length and is being conducted to the former and magnet system and the motion of the coil is increasing convection of heat from the coil and magnet system via air motion. Various ways of increasing cooling exist, and the motor system has a thermal time constant which means it takes some time to reach peak temperature and that tends to average things out with music - but not when you are using sine waves... That said, a speaker driven near its limits, thermal or mechanical, is going to be compressing a lot and not sounding very good.

[chops]

Originally posted by Ron E
IF you try to get 1000W rms, your amp will be clipping the peaks and sounding like crap, but if you listen to modern popular music, you might not notice.

Boy, isn't that the truth! LOL

[Jaminator]

Thanks for the info...
but my question remains un answered..
Why are the wires of the coil in the biggest speaker not more than 0.5mm ...the diameter of the coil might increase but the thickness of the voice coil doesnt seem to be ready for the power it is rated for and that too for 8 ohms or less.'

[Andy G]

weight !!!

[poptart]

Larger = heavier. You want the voice coil to be as light as possible. Increasing the diameter of the wire would make the coil heavier and harder to move. Obviously if you build it too lightly it won't stand up to much power, so it's a balancing act.

[Glowbug]

Voice coils aren't always very thin.

In subwoofers meant to take a lot of power, aluminum flatwound coils are sometimes used to increase power handling over round copper coils, at the cost of making the driver more peaky...

[Jaminator]

well i wonder how much current actually does a speaker get pumped when playin at its peak lets say 500 watts..
I f the current going the coils is more than 5 to 6 amp then they definately need to be thicker than what the voice coils are.

I am not sure about the AC current that get into a speaker from the AMP.

[Glowbug]

The amount of current depends on the impedance, which is frequency dependent.

You can definitely have more than 5 or 6 amps going through a speaker, some installations have more than ten times that amount of current

There's also the issue of having a former that won't fail under that kind of thermal stress...some former materials are better than others at that, others are better for lower-power applications.

[Jaminator]

Ten time more
I wonder then why the transformer coils at 6 amps are thicker than the voice coils if they both handeling the same amount of current