Originally Posted by noah katz
Some pro audio mfgr's like JBL and 18Sound publish power compression data.
As an example, the spec's for the 18Sound 12ND710 woofers in my mains are
Power Compression @-10dB 0,6 dB
Power Compression @-3dB 2 dB
Power Compression @Full Power 2,8 dB
Cool to see. Just for grins, I looked up the speaker. It's pretty sensitive at 101 dB, and rated not to explode with 450 watts.
As I understand it, the compression figures mean, theoretically, that at 45 watts (-10 dB), when the speaker would be expected to put out a little over 115 dB at one meter, it could be expected to be at about 114.4 instead.
Now for my purposes, in my current room at the levels I listen, this means the driver would not ever compress (I am a -20 dB from reference person generally).
But for those who sit farther away and listen louder, the -3 dB spec means that when the driver is receiving 225 watts, and could be expected to be outputting a bit over 123 dB at one meter, it'll be at something more like 121. FWIW, that means, if it were linear up to 100 watts, that extra hundred watts generates the additional output that an extra 25 watts should. (AIUI, a 25% power increase is about 1 dB)
And that last 225 watts, getting you to 0 dB at 450 watts input, which theoretically should get you a bit over 126 dB, would actually yield only 123.2 dB. So it takes about 450 watts to yield the output that 225 watts would produce if the system were linear out to 450 watts.
Overall, impressive (to my eyes) performance.
If my little Studio 10s performed similarly, I think I'd be looking at 95.6ish dB at -10 (max power is specified at 90 watts, but I'm using 100 because I'm lazy and it's less than a dB difference). If it's only .6 dB down, it's pretty close to linear and louder (with ten whole watts) than I'm likely ever to need them to be at my listening levels and distance. My WAG is that the Studio 10s would not hold up in the low end (relatively speaking) as well as the 18 Ssounds at -3 dB, and certainly not at full rated power. I also suspect that I'd increase distortion from the speakers significantly as I push them into compression. Luckily for me I don't have to (I think/hope/guess) although one day I'll probably get Studio 60s for the fronts just to have a little more air movin' capability.