[gruez]

but if you have two 60db transmitters, the max you can produce (from my understanding) with constructive interference is 70db , since db is logarithmic. so does that mean the transmitters in question were already transmitting at 100+db?

[jimrandomh]

Some ultrasound devices operate at power levels that would be dangerous by themselves if they were at a different frequency. Eg the article mentions "One advertised jammer emits 120-dB ultrasonic interference at a distance of 1 meter".

[jhpankow]

2x 60dB is 63dB.

[basementcat]

If the two sources are coherently phased up you can get 66 dB.

[gruez]

yeah sorry, got apparent loudness and amplitude confused.

[jcims]

While true, the energy delivered to the subject depends on the radiation pattern. A 100W light bulb can help you pick out clothes in the closet, a 100W laser can cut steel (sorta).

[fh973]

A 100W laser cuts acrylic and wood, not steel. This is the power level of hobbyist laser cutters.

[jcims]

That's in part why I said 'sorta', but Kern actually sells a 150w CO2 laser that they will support for metal cutting applications (2mm for mild steel).

I'll conveniently ignore the O2 assist for the sake of counterpoint. :)