Originally Posted by jcx
Beyer's comments are suspect - probably marketing not understanding the tech
for the same motor structure - same mag field, same voice coil dimensions - you are "free" to design to "any" impedance you want by using the same weight of copper - trading of turns count against wire size - within the limits of practical wire size, some "2nd order" limitations of fill factor/insulation thickness tradeoffs
the effect is like having a "ideal transformer" built in - the electro-mechanical driver properties are identical except for the terminal impedance scaling factor - the the electro-acoustic response should be the same as well
for Beyer to claim that the same model # with different impedance has different "speed" means they didn't follow this well known motor design principle and deliberately designed in different responses
or the marketing guys just couldn't refrain from making something up
I'm just going by what Beyer says.
And I am shocked, SHOCKED! that the marketing guys don't understand the Engineering guys!
Anyway, I'm not a motor or transformer designer.
I guess more windings in the high impedance can don't come into play, which is what I had originally suspected.
Beyer claims a high impedance DT770/880/990 is preferable to a low impedance DT770/880/990.
If what you say is true, I wonder why they would even bother marketing various impedances of the same model since a good desktop amp will drive either a low or high impedance can, so may as well just make a low impedance can and be done with it.
Beyer's claim is that the high impedance cans are designed for the desktop amp.
But I can see your point: if it's an ideal transformer, 1 mW will always lead to the same SPL, which is what Beyer claims.
Some folks argue that Beyer's efficiency claims are not accurate.
Edited by Chris J - 8/4/12 at 4:41pm