Need help ASAP with studio set-up to record e-book (Irvine, CA)

Say who you are and what you do.
Writer and producer who has a book coming out in July. The author and I have been tasked by the publisher to record the e-book and would like to record it in our in-house studio, as soon as possible.

Do you have a job specification or creative brief?
I need help optimizing our in-house studio in order to record audio for our e-book, as there are some hum and intrusive background noise in the current setup.

Gear includes:
Shur SM7B mics
Soundcraft 12 channel mixer
Adobe Audition

Is the job location specific?
We need a freelancer in or around Orange County, California. Our studio is located in Irvine, off of Research Drive.

Do you need any other services?
No.

Are you looking to pay or is this a collaboration?
Pay to hire someone

Is this ongoing work or a one off job?
One-off specific project or job

How would you prefer to pay for the project?
Hourly rate

What’s your hourly rate budget range? (USD)
$50-100 (Senior)

Do you have an estimate of the job or project length?
1-2 hours

Are you a company or individual hiring?
Company

Do you have internal sign off on the hire?
Yes

Do you need to hire for a specific city, country or place?
Yes, they need to be at a location (give location in job title)

When do you want to have the freelancer secured by?
ASAP

What is most important for this job?
Quality

How many freelancers do you want to contact you?
4-5

Do you have a job specification or creative brief?
Yes (please enter this in the description)

Does the freelancer need insurance?
Don’t mind

Where did you find Twine?
Google