How to silence an EL Wire AC Inverter?

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firedingo
 
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Re: How to silence an EL Wire AC Inverter?

Post by firedingo »

what about running a piezo and sound board to play the same "note" in reverse polarity to cancel out the sound? any thoughts?

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adafruit_support_mike
 
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Re: How to silence an EL Wire AC Inverter?

Post by adafruit_support_mike »

The noise emitters in the EL inverter are the wires in the transformer (it doesn't matter how tightly you wrap them, there's always a little room for them to move) and a minor piezoelectric effect in any ceramic capacitors used in the circuit.

Active cancellation (playing the same sound 180 degrees out of phase) is theoretically possible, but the phasing is critical. If you get it wrong, you double the noise rather than cancelling it.

The easiest solution is just to put the inverter into something that mutes sound, like a neoprene cover.

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StalePhish
 
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Re: How to silence an EL Wire AC Inverter?

Post by StalePhish »

adafruit_support_mike wrote:The easiest solution is just to put the inverter into something that mutes sound, like a neoprene cover.
Sorry to necro an old post yet again, but this is still an issue in 2018. I tried a ton of your suggestions and it ended up being that Mike's neoprene suggestion was by far the best.

I turned a neoprene fishing glove inside out and tucked my 12V EL wire/tape inverter (ID#448) inside and folded the glove a few times. It went from ear piercing at 15 feet to can't even hear at 15 feet. Even right up close a foot away it's so faint that you wouldn't even notice it was there unless someone told you. Thank you Mike!

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adafruit_support_mike
 
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Re: How to silence an EL Wire AC Inverter?

Post by adafruit_support_mike »

Glad to hear it worked for you.

Transformer noise will always be a problem thanks to the physics of magnetism. The Lorentz forces that make electric motors work also apply to the wires in a transformer. A fast-changing magnetic field produces a fast-changing physical force on the wires. The diameter and length of the wire changes slightly. That adds up to a mechanical vibration, which creates sound.

The whine can't be prevented, it can only be damped.

glymph
 
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Re: How to silence an EL Wire AC Inverter?

Post by glymph »

I found that wrapping the inverter in a small bubblewrap bag (Jiffy Bag JL000) seems to have reduced the sound to an almost inaudible level - once it's placed under a table somewhere, the Christmas tree will benefit nicely from the wire. Now I have to decide which type to get next.

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