Determining max power handling

[putergod]

I just registered, but I've been lurking a little while.
I have a few questions regarding home built speakers.
1. How is the input power distributed in a passive 3-way speaker?
2. how do you determine the max input power of said speaker?
3. how is the final speaker impedance determined? Especially in a system using multiple drivers of each type, possible varying impedances between each driver type, and varying numbers of each driver type?
4. If two crossovers are used (keep the same number of each driver type on each) and are then wired parallel/series to the speaker wire terminal, does that have the same effect as wiring a raw driver parallel/series?

Thanks for the help!

[Brett]

1: depends om where the xover points are. The half power point is somewhere between 250-400Hz, ie half the power goes on each side of this..
2: actual power handling is determined by the LF driver, enclosure and porting. You'd need to simulate it to see how much power and at what frequency the LF driver runs out of excursion. This is usually well before rated Xmax.
3: It's sually eye-balled from the impedance curve. There is no standard way of defining it to my knowledge, as except for a few designs that are deliberately designed to be flat through complex xovers, most are far from it. In reality, say 70% of the nominal impedance of the LF driver is often a good guess.
4: Series and parallel xovers are different and would require a redesign to go from one to the other. Nominal Z of the composite speaker should be the same (roughly) with well impemented examples of both types.

[Svante]

Originally posted by Brett
There is no standard way of defining it to my knowledge...

Actually there is a standard (was DIN or IEC?) that stated that the impedance should never go below 80% of the nominal impedance. I think that is why so many drivers have a DC resistance of ~6.2 ohms. (0.8*8=6.4). A bit of DC resistance in cables and coils and we are there.

Anyway, as you say one can never be sure of that the manufacturers follow this standard.

[Brett]

Originally posted by Svante


Actually there is a standard (was DIN or IEC?) that stated that the impedance should never go below 80% of the nominal impedance. I think that is why so many drivers have a DC resistance of ~6.2 ohms. (0.8*8=6.4). A bit of DC resistance in cables and coils and we are there.

Anyway, as you say one can never be sure of that the manufacturers follow this standard.

I wasn't aware of that, but looking at a lot of Z curves, I don't think many follow it too closely.

[Brett]

Originally posted by Brett
2: actual power handling is determined by the LF driver, enclosure and porting. You'd need to simulate it to see how much power and at what frequency the LF driver runs out of excursion. This is usually well before rated Xmax.

Last term should be Pmax.