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.
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.
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.
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.
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.'
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.'
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.
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.
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.
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.
Its a matter of heat dissipation. A transformer is in open air, a voice coil is in a very enclosed space.
Also a transformer has WAAAAAAY more weight to to shallow up any heat produced.
Try lifting a transformer based 1000w amplifier, then try lifting the voice coil of a speaker capable of dissipating 1000w of power. !! You may find there is a slight difference !!
Its interesting actually, about 2 years ago, Eminenence increase the power rating across their line of drivers, nothing to do with a change of voice coil, but to do with a more efficient cooling mechanism.
Also a transformer has WAAAAAAY more weight to to shallow up any heat produced.
Try lifting a transformer based 1000w amplifier, then try lifting the voice coil of a speaker capable of dissipating 1000w of power. !! You may find there is a slight difference !!
Its interesting actually, about 2 years ago, Eminenence increase the power rating across their line of drivers, nothing to do with a change of voice coil, but to do with a more efficient cooling mechanism.
Jaminator said:
The gauge of the wire used determines only the purely resistive component of impedance. This is the sole component of resistance only at DC, or 0 Hz.
But, a loudspeaker can also be thought of as a coil, and the impedance is going to be Rdc + jwL, where Rdc is the dc resistance of the wire, w = 2*PI*frequency, and L is the inductance of the coil. j is a notation that signifies that the inductive component has a 90 degree phase shift from the purely resistive part.
As you sweep the frequency, the impedance is greater than Rdc. This means that only a portion of the current results in thermal power loss.
In addition, the speaker will have a resonant impedance peak caused by the mass and compliance of the speaker and box. IIRC, Linkwitz has a derivation somewhere on his website to express this as lumped electrical parameters (i.e., as additional resistive, capacitive, or inductive components of impedance).
Finally, that 1000 W power rating might be a continous rating, a 1-hr rating, or an instantaneous rating. All 3 would yield different current figures.
Jaminator said:
You can infer:
1. The rating is essentially meaningless
2. operating anywhere near the rating will not sound good.
3. ergo, your question is essentially moot.
Your speaker has a short term operating temp of ~200-250C. IF the transformer operated that high, the resistive losses would be too high and too much power would be wasted for most purposes. We don't care much about wasted power in the speaker, it is basically inevitable.
I think of something similar I've read, like this:
"We all like sport cars and their powerful engines, and admire the speed and force they give. But we are not (and shouldn't be) proud of their high fuel consumption. It's about efficiency."
In every other kind of energy conversions, people strive for high efficiency, as high as possible. We brag about how powerful the car is, but don't brag about "my car drink a gallon within a mile", then why do so on speakers?
It's said there're some strong woofers can be plugged into the mains socket directly and give you 60Hz (or 50 in some other region). It sounds magnificent. But if they can not deliver related SPL, what's the point? A power resistor can do that, too.
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
First comment - I've never seen any speakers that can actually handle 1000 watts continuously. I've seen speakers claim that, but I believe that they only actually exist in some of the sound reinforcement drivers. So the question that arises is which 1000 watt speaker did you look at - and is it really a 1000 watt continuous speaker? A second comment -IMHO power ratings for speakers are at best misleading and are pretty low on the list for speaker designing.What the other guys said.
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You need to tell us which speaker it is. Most speakers indeed cannot handle anywhere near 1000 watts of continuous power, so almost all "1000 watt" ratings are meaningless baloney qualified by terms like "peak" or "dynamic" or "music power." (There are some drivers that can actually handle this much power, but pretty much pro sound. Or, high end autosound, I know the guys at Rockford are up to around 3000W continuous before stuff starts to break. Home speakers generally need not apply, they are just not designed to be so robust).
Looking at Ohm's law, 1000W into 8 ohms means about 11A of current. Looking at some charts on the internet, it seems like this implies a conductor somewhat larger than 2 mm in diameter. The wire in a coil is next to the magnet which should draw heat, and often ventilated by moving air...but then again, the wires are all packed next to each other and so each wire cannot radiate individually.
So if you are wondering, how could skinny little wires handle all that power...maybe they can't, and it's a "max" rating.
Looking at Ohm's law, 1000W into 8 ohms means about 11A of current. Looking at some charts on the internet, it seems like this implies a conductor somewhat larger than 2 mm in diameter. The wire in a coil is next to the magnet which should draw heat, and often ventilated by moving air...but then again, the wires are all packed next to each other and so each wire cannot radiate individually.
So if you are wondering, how could skinny little wires handle all that power...maybe they can't, and it's a "max" rating.
Now that it's up again I think I could give a proper answer as well...
The driving force in a speaker depends on magnetic flux B, length of wire in the gap l and current I. Magnetic flux is dependent on the magnet system, lenght of wire and resisitance, thus current, are dependent on the way the voice coil is made...
Someone in a German forum once proved mathematically, that the driving force with a given voltage is only dependent on the mass (!) of the copper in the gap. With thicker wire the length of the wire in the gap is shorter, but resistance is increased thus allowing a higher current which results in the same output at a given voltage.
Under these circumstances there are several reasons for thinner wires: First of all, smaller wires can be wound tighter, so the coil is smaller with a given amount of copper, and so the gaps can bei smaller and more efficient. Of course there are ways to wind thicker wires more densely, mainly by changing the form of the wire (Dynaudio uses hexagonic wires), but:
Secondly amps usually need at least 4 Ohms of impedance to run properly, so reducing Re gives no advantages like higher SPL for a given power, but only stresses the amp.
Lower inductivity Le isn't a point as well, as the lower Le is corresponding to the lower Re, resulting in the same filter frequencies...
Bye,
Spatz
The driving force in a speaker depends on magnetic flux B, length of wire in the gap l and current I. Magnetic flux is dependent on the magnet system, lenght of wire and resisitance, thus current, are dependent on the way the voice coil is made...
Someone in a German forum once proved mathematically, that the driving force with a given voltage is only dependent on the mass (!) of the copper in the gap. With thicker wire the length of the wire in the gap is shorter, but resistance is increased thus allowing a higher current which results in the same output at a given voltage.
Under these circumstances there are several reasons for thinner wires: First of all, smaller wires can be wound tighter, so the coil is smaller with a given amount of copper, and so the gaps can bei smaller and more efficient. Of course there are ways to wind thicker wires more densely, mainly by changing the form of the wire (Dynaudio uses hexagonic wires), but:
Secondly amps usually need at least 4 Ohms of impedance to run properly, so reducing Re gives no advantages like higher SPL for a given power, but only stresses the amp.
Lower inductivity Le isn't a point as well, as the lower Le is corresponding to the lower Re, resulting in the same filter frequencies...
Bye,
Spatz
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