On the K2 Plus, is it possible to turn off that damn long beep before a print starts?
I understand the need for it, but can it be shortened or turned in to short beeps? It is so loud and long it penetrates my skull and gives me a headache! lol
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Can you record and upload an example of this? My K2 Plus is 10 ft away from me and I do not believe I’ve ever heard it beep. In fact. I had to open the back of the machine a week ago and was poking around to see what was on the circuit cards. I did not see evidence of a Piezo speaker.
I never heard a long beep at the beginning of a normal print, so I would not assume that is standard behavior across all K2 Plus machines.
A few things come to mind worth exploring:
- AI detection may be enabled and triggering an alarm-style sound during startup.
- The slicer start G-code or Klipper START_PRINT macro may include a beep command, such as M300.
- It may be tied to a CFS filament load or filament-change routine.
- It could be firmware/profile-specific if they are using a different slicer, printer profile, or firmware version.
I would first ask whether the sound happens with AI detection turned off and whether it happens on a simple single-filament print sliced with the stock K2 Plus profile. If it only happens with one slicer/profile, then I would inspect the generated G-code for M300, BEEP, or a START_PRINT macro call.
do you have it plugged into a UPS? if so it sounds like the UPS it’s reaching it’s limits during heat-up, as my k2 plus does not beep 
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When I first saw this response I scoffed a bit because the beep only started after the last firmware update and it never made a sound on the UPS before. Then it occurred to me that the Firmware update COULD have changed something in the power consumption on startup, so I decided to remove the UPS from the scenario, just for $hits and giggles, and low and behold IT WORKED! The beep stopped and I can now run my K2 at night again because the obnoxious sound is no longer preceding every print. I never would have thought of this without your input so I wanted to say thank you and let everyone else , who may have also dismissed the idea like I almost did, know to give it a try if they have the printer going into a UPS. Just move it straight to the wall outlet and try again. Hoping this fixes it for everyone. TYVM!
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Hahah happy to hear, indeed there was probably some updates on the power assignment to speed up the initial heating to reduce initial prep time, and for UPS that are already working close to their limit you’ll then have some issues, sounds like time for an upgrade to the UPS 
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Sorry, I am late to getting back to this. I never consider that they sound was not coming from the printer.
What I am hearing I thought was a warning sound that a print was about to start.
I will get it printing here sometime in the next hour and then will report back.
- Dave
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Well, DUH! It is the 1500VA APC UPS! lol lol lol I swore it was the printer.
I have the same type of UPS on my BL H2S printer, I see it get overloaded when it first starts up, but it doesn’t beep. but I see its beeper is turned off.
- Dave
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Just wanted to bump this because everywhere else talked about firmware updates, menu settings, etc. As soon as I unplugged my Bambu H2S from my UPS and plugged into the wall, long (~20 seconds?) LOUD beep at the start of each print went away.
Note that the H2S display gave NO indication of a low voltage issue. In fact it displayed a “foreign object detection” status message which as a new user I mistook for an error message for the longest time, and went about troubleshooting THAT.
Anyway bump this answer and THANK YOU!!
I still leave the printers plugged in to a UPS. After a few startup seconds, they are fine and do help keep my printers going with frequent brown outs and momentary power outages. I just turned off the beepers.