I think we need to take a step back here as these claims aren't quite accurate. I'm wondering where some of this info is coming from. In reality you're not going to have any issues with 2000W unless you are running a sine wave or test tones at those levels for long continuous periods. Even then, without an upgraded charging system you will not burn up a coil in one of the AV drivers.
We need to look at what power handling means. Power handling is a rating of a safe level without thermal failure. Contrary to what some believe, this is totally separate and has nothing to do with a level of power where it can run out of excursion. The typical first failure in a woofer thermally is where the glue holding the coil windings together will soften and begin to dissolve. As that happens, the coil can end up becoming unwound. In order for that to happen the temperature of the coil must have to reach a given temperature where that glue fails. The typical cheap Chinese coil has windings wound into an adhesive that then air dries. These adhesives typically fail around 375 degrees F. A good US made coil that is dipped and baked can withstand temperatures of up to 600 degrees F. Both the drivers TC made and our drivers use these high temperature coils.
Now to compare between the two, lets look at a few things. First of all, an AV15H is 90.7dB 1W where the AP Axis is 87.4dB 1W. While the Axis can work in a slightly smaller enclosure, the AV15H is 3.4dB more efficient. Lower in frequency the system is dominated by the enclosure, but higher in frequency it is dominated by the woofer efficiency. That means to get the same SPL levels towards the upper bass range you need less than 1/2 the power to the AV15H. This is a substantial difference. The less power (less current) the less the coil will heat to begin with.
The next thing to look at is getting the heat away from the coil. A few general things to look at. The typical woofer relies on the coil to transfer heat away to the top plate and the pole. The more surface area you have with the steel next to the coil the better. This is why when all else is equal, a larger diameter coil handles more power as it has more surface area to dissipate the heat to the top plate and pole. As a result, thicker top plates are also much more effective pulling heat from the coil as they have more area. Also a kapton former is essentially an insulator while an aluminum former is thermally conductive. That means in most drivers with a kapton former you are relying on the top plate to pull almost all the heat from the coil, while an aluminum former will sink heat into the pole as well.
Now if the coil was directly coupled to the top plate and pole that is all we'd have to look at. There is however an air gap between the coil and top plate and coil and pole. Air is not a good conductor of heat. Therefore, to get optimum heat transfer you need to minimize this air gap. The tighter you can get it(without coils rubbing) the better the transfer of heat from the coil. The steel top plate and pole are very good at absorbing massive amounts of heat. The problem is that steel does not absorb heat very quickly from the air. Other more thermally conductive materials will absorb heat much more quickly. This is one of the great benefits of having the copper sleeve on the pole of every one of our drivers. This quickly pulls heat from the air gap and then is directly affixed to the steel pole. This heat will continue to "flow" from the hotter surface to the cooler surface until a point of equilibrium is reached. In the case of a loudspeaker this equilibrium point can never really be reached.
Now taking that into account, the typical failure is that the coil heats past it's limits because it can't dump the heat quick enough. The AV15H having a much tighter gap than the AP Axis will much more effectively transfer heat from the coil. The full copper sleeve on the pole has an enormous surface area to further the effectiveness of heat transfer. Now add into the equation that the AV15H is 3dB more efficient as well. You can begin to see why the AV series and TD Series are able to handle such high amounts of power with smaller diameter coils. This is why we have never gone forward with a larger diameter coil to this point. We have never needed it.
We recently did a comparison between our TD15M and some of the highly regarded pro audio 15's with 3" and 4" coil drivers. While we use a thick top plate and the aluminum former, many of them have a very thin top plate and kapton former. In reality our 2" coil driver has as much as 4x the effective heat sinking area as most of the 3" drivers and more than 2x the area of even the 4" coil drivers. Then take into account again the increased heat transfer rate with the full copper sleeve on the pole. It becomes clear to see why our TD15M has equal or even lower power compression than these massive coil drivers. Our first 4 of the TD18H+ woofers, which are the same size coil as the AV series, were delivered to Elite Audio in Green Bay here. They are being powered by a Lab Gruppen PLM 10000Q which is 2500WRMS x 4 with built in Dolby Lake processing. He uses these for live sound events where continuous levels of 110dB with 6-10dB peaks are required to be sustained at a distance of 50-75ft from the stage. Live sound is much more demanding as things like kick drum and snare are much less compressed than in recorded music. This is in reality one of the most brutal applications they could ever be in.
Again back to my point that you won't burn up an AV coil with standard charging system. One of the things to note is that in any driver as the coil heats up, the resistance of the coil goes up as well. We all know that amps put out more power into lower impedance's. This is known as power compression. On one hand you always want to pull heat from a coil quickly to avoid losing output, but on the other hand power compression also gives you a little extra added safety mechanism to keep from burning up a coil.
Let's make an assumption to illustrate that point. Say we have 2000W input to 2.7ohm coil. This gives around 27amp and 74V. We'll assume that 27 amp current applied to the coil to the 600 degree F failure point. Again this is just an assumption. The resistance of copper goes up by .0399 ohm per degree C . We'll convert F to C and we get 316C. Room temperature is typically 20C.
So we have a 2.7ohm coil heating 296 degrees C and we plug into the formula:
296 degrees * 0.00393 per degree * 2.7 ohms = 3.14ohm increase in resistance putting it at 5.84ohm total now. This is more than double the original impedance. Most amplifiers are going to be limited in output voltage regardless of impedance. We take our 74V limit again and divide by the new 5.84ohm resistance and now have only 12.7 amp. Again we determined that it would take 27 amp to reach the 600F failure point and we are nowhere near that point due to the power compression. If we started out applying the 2000W input to the 2.7ohm coil we would likely see the coil come to an equilibrium point well under the 600F point and it would not be near failure. Combine this power compression aspect with the high heat sinking area of the AV coil and the increased thermal transfer due to the copper sleeve on the pole, and you wont' burn up a coil with a standard charging system.
John
