←back to thread

Amplification of electromagnetic fields by a rotating body

(www.nature.com)
142 points keepamovin | 2 comments | 13 Oct 24 07:23 UTC | HN request time: 0.002s | source
Show context
colanderman ◴[17 Oct 24 20:02 UTC] No.41873209[source]▶
Apparently this effect applies to sound waves as well: https://arxiv.org/pdf/2005.03760
replies(1): >>41874452 #
1. ricardobeat ◴[17 Oct 24 22:29 UTC] No.41874452[source]▶
Does this mean impossibly small subwoofers? Would the rotating part have to precisely match the audio frequency to be amplified?
replies(1): >>41874795 #
2. foobar1962 ◴[17 Oct 24 23:18 UTC] No.41874795[source]▶
The mechanical driver part of the subwoofer might be able to be made smaller, but the surface that moves the air still needs to be large - there is a relationship to the wavelength of the sound involved that I no longer remember. This is why tweeters are small.