Comparing sensitivities

[Grahamt]

Hello,
I have been looking at the different sensitivity ratings and wondering how to compare them.

For example,

An 8 Ohm woofer with sensitvity of 86 dB (1W, 1m)

And a 6 Ohm Tweeter with sensitivity of 88 dB (2.83V, 1m)

Is there a formula or something to convert the 2.83 V rating into 1W, 1m)?

Thanks in advance,
Graham

[BillFitzmaurice]

I believe it's Ohms law, or a derivitive therof. The voltage required for one watt is the square root of the impedance load; 8ohms= 2.83v. 4ohms =2 volts; 6 ohms =2.44 volts, etc.

But what really matters is comparing everything with the same voltage, not wattage, as an amp is a constant voltage device and all the drivers in the system will see the same voltage, not the same wattage. In your case the 8 ohm driver is getting 86dB/2.83 v, the tweeter 88dB, so the tweeter may have to be padded by 2dB to match the woofer. BUT- woofers seldom actually get their rated SPL broadband, it's usually measured as an average, so even more padding may be required.

[Grahamt]

Thanks Bill, very helpful.