Clearly communicate your ideas incorporating both your expertise - make sure the other party understand you are not undermining their opinions

One thing that can help is clear & honest communication, but with respect kept at the forefront. Both parties are professionals and experts in their own ways. It’s important to maintain equal respect when communicating your emotions and disagreements. Say how you feel and ask how we can meet in the middle. Don’t be so stuck to exactly what you want and show that you’re open to finding a compromise that can work for both parties.

It is quite possible that a singer could end up at odds with their recording producer. If the project has been initiated by the singer, hopefully he or she had in depth conversations with the producer being hired long before the project began. If the project is someone else’s, the situation is more tricky and a fair bit of diplomacy is probably called for. A singer should not expect that a producer who normally records pop singers using lots of technology to modify the voice will go along with an approach to recording that is more natural. Or vice versa. So best is to do the research before money is being spent in the studio. It’s possible that the singer could end up either turning down a certain job or expanding their sonic horizons.

As a singer, you must educate yourself about recording methods and acoustics. You must know what sounds you like and which you don't and as an artist you have the right to express that to a producer.

Explain the vision, nothing hurts to try in a truly creative environment. Some battles aren’t worth the fight, but when it is, if they respect you as a musician and passionate about the art they will see your vision through. If it doesn’t work for the producer allow them to express they’re vision and see it through.