Fixing audio recorded to low?

Not sure if there is a better place on here to post this but i've got audio recorded from a presentation that I'm editing together, and the camera operator got audio from the sound board guy for the whole event. Well i guess he was just giving him audio that was going out of the speakers in the house, so the volume out wasn't extremely high. So the audio we got was low, and i mean low. Like -30db's low.

When i jack the volume up, i get the obvious high hiss sound that comes with boosting up audio and some background mud sound. Does anyone have any recommendations on where to begin with improving this the best i can? or any plugin's i could purchase to help?

search / post at pro audio site gearslutz.com.
you'll probably need to maximize it then denoise it using something like rx www.izotope.com/en/products/repair-and-edit/rx.html

without any 3rd party tool:

try to apply a Compressor effect (there a Vocal presets), and in the Audio Inspector, Hum/Background removal

Hi Brady
Know this is an older post, but been away.

Go to the clip and set the audio somewhere between 0 or +6 (default is +12)

Now apply the "Gain" effect in Effects "Audio"
In the inspector pane for the clip, scroll down to the Gain effect and "boost" the volume increase.
Boost till the clip has enough level. Since you reduced the original volume level, you now have some additional headroom to finesse the final level by using normal clip audio level adjustment.

Now apply an EQ effect.
Open the EQ plug-in and click on the analyze button as the clip is playing. You will see the waveforms. You can remove specific frequencies that may be causing hiss and distortion. Try to find a section that is mostly the "noise" you want to remove and work on that. You will need to attenuate the problem frequencies and use the "Q" width parameter to try to limit the attenuation (cut) to only the problem.
You can "color" the sound if need be, and there is the ability to switch to a 30 band EQ for narrower widths if needed.

The hum and noise filters may also help.

Hope this helps, Greg

There are 4 main steps you can take to salvage nearly any audio.....depending on the end use.

1. apply a de-noise. The Final cut de-noise is OK, but some third party ones like sound soap or izotope are better.
2. apply a de-reverb (if it is from an indoor shoot and you are getting too much room sound). There is a cheap one from crumple pop that does a decent job.
3. Use the eq to adjust. 240khz frequency is the depth of a voice, 500k is the muffled frequency range, 1k is the nasally range, 2k is the rasp, 5k is the 'esssss' range and 7k+ is breathiness or the airiness (also where the hiss lives). Often when you remove noise you also muffle the voice a bit.
4. Finally, you can increase the level via the volume, or by using a limiter or compressor to get the volume back up to a reasonable level. The loudness in FCPX is good as a start.

I've been an audio editor for approx 20 years and this is my workflow.