I hope you are managing to stay cool during this incredibly hot summer. Here in Memphis we are faring much better than other parts of the country. Today's summer rain is much welcomed. Most days I have to keep a fan blowing in my studio or I wouldn't make it. Last week I did a phone patch session that lasted over an hour during which I turned off all fans and AC. By the end of that session I was working up a sweat. The joys of working from home. As it turned out the producers put music behind the VO track which would have masked any noise that my AC might have made. Here is one of the videos that came out of that session. The producer in me can't help but notice that YouTube dumbs down the audio quality of the voice over a bit.
In an ideal setting I would have an HVAC with large enough ductwork and vents so that the flow of air did not make noise. Also the attic AC unit would be far enough away so that you would not hear any mechanical noise. In previous studios that I designed and built that was the case. The work around in this location is to turn down the AC an hour before the VO session. Cool things down first and then it's not so bad.
This week I did a corporate narration for a client in England who will not be putting any music behind the voice. That is when the shortcomings of your studio can be exposed. That is why I went to a great deal of effort when I first moved in to build a dozen sound absorption panels. These are filled with mineral wool insulation that is acoustically rated. While these don't control outside noises they do dampen and control the sound inside the studio.
Here is an excerpt from that session. You'll notice that even though I am using a high quality condenser mic (U-87) which picks up everything the room is pretty quite. A noise gate also helps.
That's all for now. Stay cool. And stay quiet.