Can I improve my audio?
 

I'm was taping an interview (just a hobby, not for $$) in my house when my shotgun mike failed. Wasn't the battery, it just quit (but I've learned enough from this site to monitor my sound with headphones so at least I knew there was a problem!)

With no other choice, I shot the interview with the on-board mike. I was close enough so that the volume is fine, but it sounds, well, hard and amateurish.

I edit in FCE. Are there any filters that I could use to soften the sound a little bit so it doesn't sound like the talent is in a concrete box?

Just a little additional info: I was shooting in front of a green screen with the idea of keying in an outdoor scene, but the audio is now definitely mis-matched with an outdoor scene.

One final question: Is it possible to improve the sound when shooting indoors by hanging blankets, comforters, pillows or other materials in a room? Sorry if that sounds bizarre, but I think the hard walls make the audio hard.

The final question: Yes indeed. Soft materials makes for "soft" audio. Also: Hard materials with uneven surfaces softens audio, too (egg cartons for example). That's because it spreads the reflections so much they die fast.
First question: Wild guess, because you don't say much about the quality of the recording, and I don't know FCE. You'll probably want to use some equalizer and lift the bass region (150 - 400 Hz?) a little. Experiment. To make it sound like outdoors it would help if you added a track of the right outdoor atmoshere. Anything appropriate to the area and or the mood you want (dogs barking in the distance, neighbours mowing the lawn, cars passing, birds singing, people passing by. Or just the soft wind touching the trees.
You will find that the proper "drawing" of the environment says more about time and place than the right colouring of the voice recording. But that too, of course, helps.

Someone who knows your camera can perhaps give you better advice. Or you could post a clip somewhere and hope someone will listen to it.

Thanks for your input on my last question, and your thoughts about adding some ambient sound.

I have tried to experiment a little, but the filter names mean nothing to me, and the adjustment sliders for each filter are even more foreign. I'm a complete novice at this so I was hoping someone could guide me a bit. If not, I will just keep on with the trial and error method. I will try to bring up the lower frequency if I can.

If it matters, I used a Sony TRV950 for the shoot.

Simon, I love your signature!

Can you color correct? In other words, do you understand the principle?
In the video to Audio world:
Black= low frequency audio
Skin tones=midrange
White=high frequency colors
Blur=Reverb

If you can remove some of the "muddy Skin tone" or audio in the lower midrange areas, say around 300-600hz, you might be able to clean it up.
"Add Pedastle" by slightly increasing the bottom end. You'll create a more solid foundation on which the rest of the audio is heard.

Bad analogies for some, but color correcting and EQ'ing audio are basically the same thing. Just different mediums.

For a built-in camera mic, the TRV-950 probably has one of the better! I use the 950 myself. Although the house mic is idle most of the time, I don't hesitate to use it for odd stuff. It does pick ut a lot of detail, which means the track can be manipulated in post. There will certainly be a bit of motor noise on your recording. You should get rid of that, and the best way I know is to use Sony Noise Reduction (a plugin that will also repair the sound of your vinyl records when you get around to burning them to CD).
Apart from that, I believe the distance between the speaker and the mic plus the characteristics of the room itself is your main problem - not the quality of the mic.
Like I said, I don't use FCE. But the filter you need most will probably be called something like EQ, Graphic Equalizer or just Equalizer. A compressor might do you some good, too. It will raise the volume of an audio track while keeping the peaks below a set level.
If you find that FCE's audio capabilities are too bad you might want to look at Sound Forge. But you're probably saving up for a new shotgun right now :-)

Try to find the reverb main frequency and eq it down a bit.

You can gate the reverb tails using a gate with variable attack and release. Don't let the gate close completely because then you will notice it even more since there will be a pumping effect. The gate will "close" to a predetermined level after each phrase.

Mask it all with the sound of nature in glorious stereo.

It will not be 100% but if the reverb is not too heavy you will get away with it.

For noise removal state of the art there is always www.waves.com restoration bundle that works great within limits (the best?) but for a price.