"Efficiency = ( B^2 * L^2 ) / ( R * Sd^2 * Mms^2 )
B = magnetic field strength
L = length of wire
R = resistance
Sd = surface area
Mms = mass
Not sure but I think he's overlooking mass. As a denominator, it would at least partially offset the his length of wire. Seems like more wire in the voice coil = more mass you have to move.
Would you care to explain what Mms is then? How about mechanical Q (Qms). Mass is taken into the equation. And you are correct it is a detractor, as stated in the above formula.
Npdang even says it's a very simplified explanation. Fact is though, that it's still accurate. You're calling out one of the most respected members of the car audio community. He's also well known in home audio circles. He knows his stuff. If you want to challenge him, then by all means do so. I'd like to see it. He's very professional, and very approachable. He also deals in facts, and not opinion, unless you're talking subjective sound quality analysis. He's also the founder of that forum. The sub on the front page is designed by him, and quite a piece of equipment.
So, you have yet to prove to any of us "kids" that you have objective, factual data to dispute what he states. Which, remember he states as "can be beneficial", not will be beneficial.
You haven't provided any data to support your conclusions. Now I will admit, again, that it's a very simplified explanation that we're giving. If you have some real world experience that produces varying results, then great. I have real world experience that reinforce Npdang's statements.
Also, in the case of subs, you have a lot more mass to move. More power can equate to higher output over a moderately more efficient sub with a higher impedance. Also, we're talking about low frequency response. Hoffman's Law has a whole lot to do with it.
You stated same sub. Is it the same sub, in the same box, ran off the same amp, just a different impedance? There are so many variables that can affect how a sub performs beyond just impedance and power supplied.
Comparing two different home audio setups, (6 ohm to an 8 ohm), you once again, haven't supplied us with models, or any other data than "the 6 ohm was louder". Once again, low extension, drivers, box alignment, and so many other variables that you haven't stated need to be taken into account.
I'm not disputing that one was louder than the other. There is so much else that needs to go into that statement before you can objectively debunk anything Npdang has said.
You won't make many friends by trying to trash Npdang. Like I said, he's extremely well respected, and one of the most approachable people in car audio. He is without ego, and the elite attitude that comes with many of the big shots in car audio.
So, again, I ask you to really challenge his statements, from a technical standpoint.
