How to add an UPS beeper volume controller so that I can make it sound quieter when it beeps?

Question

I've an EATON 5E850iUSBDIN 850VA/480W UPS.

This UPS makes a very loud beep sound both when it's first plugged into the mains(short beep) and when it's first turned on from the button(3x longer beep) (I'm not including the case when it beeps because the mains power is cut off).

I would very much like to somehow attach a volume controller so that I can make this beep quieter for two reasons:
1. thin walls - I worry about disturbing the neighbors with the loud beeping sound (mainly during the night).
2. this UPS constantly uses 7.5W even when nothing is plugged into it (this is after the battery is already well charged) - and due to 1. I'm keeping it plugged in full time. (as a side note: if I turn the UPS off from the button it consumes 7.0W constantly, even though the battery is already charged)

A volume controller would allow me to unplug it whenever I want thus saving power (and noise).

What kind of volume controller should I attach and where/how to wire it ?
and Would adding it possibly affect the UPS functionality ?

EDIT: picture of the beeper/buzzer inside:

Answer 1

That's a common self osscilating Piezoelectric buzzer. You can lower the volume electronically by reducing the voltage to it. A few 1n4001 diodes in series would work. A low ohm resister in a pinch. Or you can just snip it off, or pierce the membrane inside with a screwdriver

But a mechanical method works fine too. Some tape over the hole, or some cotton in the hole. Both. Muffles the sound.

Answer 2

I know it has been a while, but I do hope that this answer will help those who don't want to tamper with the electronics.

the simplest solution I found was to drown the speaker in hot glue. just place the nozzle of the gun into that hole and fill the speaker with hot glue. it will muffle the sound to a point where you have to hold your ear against the unit to hear it. worked very well on silencing my EATON 5E 850I.

Answer 3

Another late to the party offering, but adding for the sake of future google link followers...

My personal solution for taming these kinds of beepers is to simply stuff a bit of neoprene (black rubbery sponge like material often found as shock absorbent matting in many products), flip-flop/thong foam (known as L200, L400, L800, etc. The number indicates firmness/density of the foamed rubber material), or anything spongy into the hole. Be aware, stuffing too much, too tight, can press against the disk changing the resonance and in effect increase the noise/frequency. However, simply stuffing some dense spongy material in the hole, with slight contact to the disk, if any, can absorb the majority of the vibrations, either mechanical or acoustic, while still allowing an audible amount of sound through. Leaving a small bit of foam protruding allows for easy removal or modifying the amount of foam therefore the amount of deadened sound. Ill usually peel a pinch of neoprene off a foot pad or something from an old salvage device, roll it between my fingers, then get it into the hole before it re-expands leaving a little tail sticking up to pull it back out if need be (twist the same direction as you rolled it when removing). Worse comes to worse a pair of good long point tweezers can fish out foam that gets stuck. Easy to undo if one wants to return the device to stock (ie, for sale, noisier environment, etc), I've used that trick on just about every UPS, multimeter (continuity beeper), and random annoyingly loud devices I've owned.