First, an anecdote from Jeff Bezos, Amazon founder:
One of the programmers set up the computers so that a bell would ring
every time an order came in. A great novelty at first, it quickly got
annoying and had to be turned off.
Then an idea of how to live with your "bells" (you have several ones!). Setup two types of alert. On new order comming:
- first display visual alert (changing color of a block on the page,
blinking tab title in browser or favicon to focus attention to the
order page, notification in Chrome etc.). Visual alert is less distractive for operator and other people in the office.
- use sound alert in case of no reaction from operator within reasonable period of time.
- change sound alert as a function of time, starting from quiet and gentle sound to more loud and urgent one.
- use snooze while signalling.
This approach allows to minimize bell rings and sound distraction in your office.
There is also important psychology trick which I've mentioned in a comment. If the sound alert is mandatory you could use false dilemma effect, (choice without choice). It's a situation in which limited alternatives are considered, when in fact there is at least one additional option.
An example is a question: "Would you like a tea or coffee?" which pushes user to choose between two options while he actually would prefer just a cup of water. This is NLP trick ).
For sound alert it could be used, too. Let user chooses a sound from a set. Making a choice, user will feel a freedom of choice and control. While actually it's only illusion of control and choice from limited set of options is actually "choice without choice".
And more anecdote from Inmates Are Running the Asylum by Alan Cooper concerning bad designed in-flight entertainment system:
With cash collection connected to content delivery by computer, the
flight attendant had to first get the cash from the passenger, then
walk all the way to the head end of the cabin, where the attendant's
console was, enter an attendant password, then perform a
cash-register-like transaction. Only when that transaction was
completed could the passenger actually view a movie or listen to
music. This inane product design forced the flight attendants to walk
up and down those narrow aisles hundreds of extra times during a
typical trip. Out of sheer frustration, the flight attendants would
trip the circuit breaker on the IFE system at the beginning of each
long flight, shortly after departure. They would then blandly announce
to the passengers that, sorry, the system was broken and there would
be no movie on this flight.
This is a hint of why some sound speaker in your office could be non-working suddenly.