Higher sound pressure from a MAX98357A ??

[espena]

I'm working on a IoT doorbell circuit: https://github.com/espena/dual-button-doorbell. It's a hobby project, and it works very well except for the speaker's sound pressure being a little bit on the low side. I'd wish for the output to be more audible.

I went for the MAX98357A amplifier (U2 on the schematic) - assuming 3W output would do the trick. Still, the sound pressure is a bit too low using this 3W / 4ohm speaker: https://no.mouser.com/ProductDetail/DB-Unlimited/SW1000304-1?qs=DPoM0jnrROUOabiEq0xXSQ%3D%3D.

The sound pressure is rated to 106 dBA (EDIT: at about 10 cm), I assumed that would suffice (wrong?). Don't know if my actual output is anywhere near that limit. If I increase the volume further, it seems to overdrive the amp/speaker.

I've tried a 5W / 4ohm speaker as well. It resulted in better sound quality, but the sound pressure is of course pretty much the same.

Having no experience with audio designs, I would love to hear from you: What would a proper design look like if it should replicate the audio output one usually expects from a loud doorbell? Another amplifier chip? More watts? Different kind of speaker? Additional circuitry? Other suggestions..?

Ive seen some very small designs emitting impressive sound levels - so how do professional designers go about to get there?

Regards

Espen

[TimFox]

From a typical website list:
100 dB(A) is a jet take-off at 305 meters.
110 dB(A) is an auto horn at 1 meter, a normal sound level at a teen-age boomety-boom concert, and a typical threshold of pain in a human ear.
Note that this reading is meaningless for a source unless you specify the distance from the source.
How much sound does your dog need to bark at the door?

[espena]

Thanks for pointing that out. I think the 106 dbA rating was specified at 10 cm distance

[TimFox]

In my house, the distance between the doorbell sounder and my living-room couch is roughly 5 meters, so by inverse square law the sound level would be (5/0.1)² or 34 dB lower.

Edit:  corrected calculation

[Zero999]

Use a more efficient speaker such as a reflex horn. It won't have such good sound quality but will produce a much louder sound, given the same power level in.

[moffy]

With a speaker it is important to seal the back from the front so that air doesn't flow directly from front to back severely reducing its efficiency.