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Do almost all modern smartphones use piezoelectric speakers for both the ear speaker and the speakerphone speaker?

The reason I ask is because I rinsed off my waterproof smartphone (which I've done dozens of times) and the speakerphone speaker now sounds horrible: the volume is very low and the sound is exceptionally "tinny".

Its done this before after rinsing it off, and I can usually just make a call on its speakerphone to resolve the issue. But this time, after making several speakerphone calls and letting a single bass-filled track of music play repetitively for an hour, the sound quality is still poor.

In order to determine how to hopefully resolve this issue, I first need to understand what type of speaker is likely involved. The brand is Samsung, if that matters. Is it almost surely piezoelectric?

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    \$\begingroup\$ It is unlikely to be piezoelectric. Most speakers and earphones are electromagnetic. \$\endgroup\$ – JRE May 10 at 22:13
  • \$\begingroup\$ is your smartphone really "waterproof", or is it "water-resistant"? \$\endgroup\$ – jsotola May 10 at 22:37
  • \$\begingroup\$ I guess put it in a bag of rice. If same , it’s not moisture damage but perhaps corrosion. \$\endgroup\$ – Tony Stewart EE75 May 10 at 22:40
  • \$\begingroup\$ A piezo transducer sounds awful as a speaker. A piezo is usually used as a one frequency beeper. \$\endgroup\$ – Audioguru May 11 at 0:21
  • \$\begingroup\$ @JRE and Audioguru Thank you both. I didn't realize electromagnetic speakers could be made with such impressive output in such a small form factor. \$\endgroup\$ – RockPaperLz- Mask it or Casket May 11 at 5:51
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No, on the contrary, most if not all of them are common dynamic speakers, just small and usually employ an neodymium magnet.

This is the Moto G 3rd generation speaker for example

Many (if not most today) have a slightly different configuration from this one in the image, with a larger square coil all around the diaphragm (in order to increase power density, having the biggest possible coil for that frame).

Piezoelectric speakers are limited to trebles, and even then their frequency response is extremely limited and usually far from ideal (from being flat) in the desired operation range.

They'd never be able to reproduce all the range a smartphone speaker can (even considering how poor they are).

The reason your speakers got damaged is most probably purely mechanical, water getting in the magnet and between the coils or behind the diaphragm will absolutely destroy the sound quality, and to make things worse it can be very stubborn to evaporate from there.

Not to mention it can also cause rusting of the metals inside, and if they rust they can swell and lock or friction against the coil.

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  • \$\begingroup\$ Excellent answer. Thank you. Upvoted. If you happen to have any more modern photographs to add to the image you provided, that would be great. If I'm understanding you correctly, the speakers in the smartphone are most likely just a tiny rendition of a "classic" speaker that you would buy at any electronics store. Is that correct? \$\endgroup\$ – RockPaperLz- Mask it or Casket May 11 at 5:49
  • \$\begingroup\$ I was thinking a little more about your answer. Since the device is intended to be used underwater, why would the manufacturer use a part that is so susceptible to water damage (and difficulty drying)? Are there no other reasonable alternatives? \$\endgroup\$ – RockPaperLz- Mask it or Casket May 11 at 6:00
  • \$\begingroup\$ @RockPaperLz-MaskitorCasket Here's a more modern one maxbhi.com/images/detailed/3244/… \$\endgroup\$ – user2934303 May 11 at 16:47
  • \$\begingroup\$ @RockPaperLz-MaskitorCasket But in all cases, water getting into it should not have happened once it's waterproof. The front of the speaker is waterproof anyway, even in the non-waterproof phones, because the diaphragm and suspension are impermeable. What changes in a waterproof one is that it has a tighter seal around not to let water enter around it. You should also consider the probability the water didn't get into it, but it's stuck in front of it somehow. Which phone you have? \$\endgroup\$ – user2934303 May 11 at 16:53

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