It´s a 2 year old Toshiba aircon, adequately sized for the room, cools well, no complaints except I believe the blower should be less noisy, totally subjective I admit, doesn´t seem to run, "round". The compressor can´t be heard.

Can you change something in the blower? Or replace just the blower?

Some units run noisier than others. Some manufacturers advertise their units quietness as a selling point. Did it always make this noise or has it just started?

Some units run noisier than others. Some manufacturers advertise their units quietness as a selling point. Did it always make this noise or has it just started?

excellent reply ^^^^

If it always made this noise. then it is either a design characteristic or a manufacturing defect, Check to see if other similar unit make the same noise, if they do it is design characteristic, if they don't, it is probably a manufacturing defect, and should had being addressed while the unit was under warranty, now it might be addressed at your own cost.

If the problem just started, then it might be do to normal mechanical wear and tear , and could be remedied by your A/C tech,

or it could be a loose plastic component vibrating,

Try putting hand pressure on some of the plastic housing components to see if the noise decreases or stops. I once stopped an annoying A/C ratle by simply sticking a piece of fold-up paper between two plastic components ,