What's with 4 ohm speakers?

I should probably proof-read better before posting
>The moving mass Mms works as a capacitive inductance Cmes.

capacitive impedance

>When cross-over designers compensate for that with a series load power impedance increases at those frequencies and power dissipated decreases.

series load impedance increases at those frequencies and power dissipated decreases.

Or is there some type of industry standard and everyone measures these type of things the same way?

They are supposed to, anyway. Of course the room is important, about 1/2 of the total system sound, IME.

>The statement is ambiguous. We know that doubling power is 3db, and that there is or should be a direct correlation with driver output. Since this is so then driver output is also proportional to power.

Nope. You're confusing voltage and power where power is voltage squared divided by impedance.

Sorry - not confused. I am quite literal though. If you are saying there is not a proportion then you are contradicting yourself. But I suspect we are arguing semantics. To clarify I was simply stating that +3 db more watts is twice as many watts.

Amplifiers which don't accommodate these physical realities with terminal voltage that's a fixed multiple of input voltage regardless of load impedance aren't universally useful in high-fidelity applications for speakers having impedances that are otherwise compatible causing neither instability nor power dissipation issues.

Certainly this is true. However not all speakers have this requirement of an amplifier- such speakers can be incompatible with amps that are capable of Constant Voltage behavior. Rather than repeat myself ad naseum I invite you to go back to an earlier point in this thread an look for a link I dropped to an article on the Voltage and Power paradigms, so you can catch up on the conversation.

Whats' with 4 ohm speaker's? Its the damn drivers. Many of the tweeter's on the market from RAAL, ScanSpeak and other's have a 4 ohm impedance.

In tweeters the mass of the voice coil becomes an issue so I do not doubt that they would use 4 ohms over 8. All things being equal that would cut the voice coil weight in half.

I was incorrect on the RAAL ribbon's. They are all 8ohm impedance. ScanSpeak has 36 different tweeter model's in production. 23 of those models have 4ohm impedance. Vifa currently has 18 tweeter model's that have 4ohm impedance.