audtatious wrote:They look nice. 87db sensitivity does not seem very high (granted, 6ohm instead of 8). I'm used to 1w/1m specs, how do you compare that to 2.83V@1m?
Well using the 1w/1m to me seems pretty universal. It means, regardless of impedence (ohms) at 1watt of input, the speaker will put out XdB's whatever it's efficiency is.
Using a 2.83v/1m is useful when building speakers from scratch using raw speaker drivers (tweeters, mids, woofers, ect...) because an amplifier is technically a voltage source and not a "wattage" source.
So you can pair up an 8ohm,
[email protected] tweeter with a 2ohm,
[email protected] midbass and when hooked up to an amp, they will produce the same SPL's even though one is getting 1w of power and the other is getting 4w of power at 2.83v. Ultimately that's what's most important. Having one put out 90db and the other put out 80db would create an issue.
It however can also give missleading results when, say, subwoofer companyA has a dual 2ohm sub and they give the sensitivity as
[email protected]/1m wired in parallel, but companyB rates their speaker as 88db@1w/1m and it's a single 8ohm voice coil. Once you do the math, you will find that companyB produces a more efficient subwoofer than companyA. However, companyA produces a more sensitive subwoofer.
Efficiency does not equal sensitivity
How a 2.83v/1m rating works out is like this:
At 16 ohms, 2.83v = 0.5 watts.At 8 ohms, 2.83v = 1 wattAt 4 ohms, 2.83v = 2 wattsAt 2 ohms, 2.83v = 4 watts...
So a 2ohm speaker rated at 90db@1w/1m would also be rated
[email protected]/1m, because at 2ohms, it would receive 4w instead of 1w.
-Everytime you double the power to a single speaker (negating power compression), you get 3db more output.
-Everytime you double the cone area (meaning two speakers, or an identical speaker but twice the cone size [which is impossible]) but keep the power the same, you get 3db more output.