Each orchestra has its own way of recruiting new members. The audition rules, committee, format, duration and repertoire will vary a lot from one orchestra to another even within the same country so you should be prepared for anything. Sometimes, musicians are hired without audition but it is rare.
You can find information about available jobs online ( www.musicalchairs.info for exemple) or in publications such as the Das Orchester magazine in Germany. You need to send them your resume and contact details and wait for the invitation. Some orchestra will invite everyone, others will invite selected candidates based on age, experience and recommendation . Having your teacher or someone you know giving a call to one of the section members to support your candidacy can help you getting an invitation.
If you are invited, they will send you a letter of invitation with a list of solo repertoire and excerpts to prepare. European orchestras tend to put more emphasis on the solos in general as in North America, the excerpts are more important but again that varies a lot from one place to another. In any case, you should take everything you have to play seriously!
The jury will be composed of members of the vacated position's section, principal players of the larger group (winds, or strings), and other selected members of the orchestra( for ex. the concert master) . Some orchestras have the entire orchestra voting. The chef conductor may be present and have a veto right on the final decision.
There are usually 3 rounds to an audition. (it can also be more or less) After each round, the jury will eliminate a certain number of candidates and the remaining people will move on to the next round. It is common for an orchestra to not hire anyone after 3 rounds if they aren't satisfied with the level of playing they are hearing. In that case, they will have another audition a couple of months later. Another chance for you!
Most candidates are eliminated in the first round for accuracy, intonation, rhythm, tone quality problems or lack of musicality. The jury can also cut someone after a few bars if they think they've heard enough. It isn't pleasant if you are the "victim" but having sat in many audition committee, I can tell you that an audition day is long and tiring for jury members and if someone just isn't doing well and has no chance of winning, they will try to shorten the day a bit by eliminating that person immediately. That's life... If this happens to you, don't take it personal. Learn from this experience, tweak your playing and try again.
Making it to the second round of a professional audition is quite an achievement in itself. It means that this particular orchestra consider you a contender for the job and wants to hear more of you. There will usually be only a few candidates left. At this point, it becomes a matter of physical and mental endurance. They already see something in you so keep giving it to them!
In my experience, the hardest excerpts will be asked in the second round to see who's got solid nerves and chops. They can also ask you to sight read something.
And finally, if you survive the cut, comes the final round. At this point, there are normally only one or two candidates left. If you've made it that far, it's already a moral victory and you should be very proud. Don't get too excited ! You're not done yet. You might have to play a whole movement of the concerto with the remaining excerpts on the list and more. Considering that your "rival" is probably just as skilled as you, it's really about your personality as a musician here. They will look for someone who they think will fit the section and the orchestra the best. You might also have to play with the section and/or the entire orchestra.
If you win, congrats! You will generally get a year trial on the job after which the panel will decide to give you the job for life provided you don't mess up and keep a decent level of playing.
Winning a position in an orchestra is a remarkable achievement for a musician considering the expectations and the competition. I personally went through around 25 professional auditions not counting the ones for schools and festivals. Sometimes I won. Sometimes, I made it to 2nd and third rounds. Other times, I thought I played great but was eliminated immediately or thought I didn't play so well but still advanced.
You really can't predict what the jury will think. You just have to go there, do your best and hope the planets will line up on you that day. If things don't go well, don't be discouraged. You didn't fare worst than most people on that day.
Once the audition is over, it's no use making up conspiracy theories about how unfair the jury is or the audition being "rigged", etc. That's a loser attitude. Learn from the experience and tweak your playing for the next one. If you know someone on the panel, try to get some feed back if possible.
In the last post about auditioning, we will go over a few good tips and strategies to prepare yourself for the big day.