Eliminating Echo

[theperfectsong]

I just did a series of interviews today in a large room that I knew had a hollow sound, but I had no choice. The question is, how do I get rid of the hollow or light echo sound for a flatter, studio sound?
I used a Marantz PMD660 recorder, Heil Microphone and for software I used Adobe Audition. I've spent years adding echo effects, but I've never had to soften or eliminate it.
Any help is most appreciated!

[EclecticMix]

I think you're pretty much stuck with it. Once the sound starts bouncing around, it just becomes part of what you're recording, and I don't know of anything that will take it away.

If you had no choice then you had no choice. I did an interview in a stairway, so that's just the way it goes sometimes.

Cheers -

george

[theperfectsong]

I was afraid of that. I'll just go with it. Thanks!

[WyethDigital]

Does your software have a preverb filter? I've used that with a modicum of success in the past.

Eric

[Soccer Shout]

Don't know if this will work, but try applying a noice filter that will take away everything under, say, -35db.

If will affect overall quality but it might help with the echoes. Play around with the parameter and do the A-B comparisons to see what sounds better.

Wavepad is a simple, free program that will do this kind of processing.

[pwfenton]

I just did a series of interviews today in a large room that I knew had a hollow sound, but I had no choice. The question is, how do I get rid of the hollow or light echo sound for a flatter, studio sound?
I used a Marantz PMD660 recorder, Heil Microphone and for software I used Adobe Audition. I've spent years adding echo effects, but I've never had to soften or eliminate it.
Any help is most appreciated!

I think that if such records were kept, this would be the most asked audio question. The answer is that there is nothing you can do that will help in any significant way.

Theoretically speaking... I think it could be done.. it's all math after all. But it's genius level math, and so far the technique hasn't been discovered. I'm sure it would involve going back and making a careful analysis of the space. It wouldn't be simple, even if it were possible.

In the future... things like highly directional (shotgun) microphones or very close mic placement are the only ways to get a decent recording in very live spaces.

[Soccer Shout]

Okay, now I'm interested to see whether my idea would work.

If you don't mind, send me clip and I'll run it tonight.

soccershout@gmail.com

I'll let you know how I got on.

[pwfenton]

Okay, now I'm interested to see whether my idea would work.

If you don't mind, send me clip and I'll run it tonight.

soccershout@gmail.com

I'll let you know how I got on.

I think you will find that what you are suggesting will turn a recording that is hard to understand... into a very strange sounding recording that is just as hard to understand. A gate may remove reverb in between the words you need to hear... but that isn't the problem. It's the reverb that competes at he same time as what you want to hear,

[Soccer Shout]

I'm sure you're right...I just want to see.

(By which I mean 'hear', obviously.)

[EclecticMix]

Actually, a gate will probably end up sounding very distracting, though give it a try to confirm. The only thing I can think of would be to try eliminating noise, though that may also be quite tough. If you've got ten seconds of the silence of the room then perhaps using that as a profile to be removed may be helpful, but probably not to a significant level.

Cheers -

george

[zircon]

It's basically impossible to get rid of natural reverberation. If you had an impulse response of the room's reverb made with the EXACT same recording device, you MIGHT be able to do some phase cancellation but that's really really unlikely. Your best bet is to simply make sure you have the mic as close as possible to whatever you're recording and try not to record in rooms with bad acoustics.

[kelvin0mql]

It's basically impossible to get rid of natural reverberation. If you had an impulse response of the room's reverb made with the EXACT same recording device, you MIGHT be able to do some phase cancellation but that's really really unlikely.

But... but... but... I've SEEN them do this on TV!

Why can't we just get the un-reverb hyper-genius-math program they have on that Numbers program on TV? It's just an algorithym.

~heheheh~

[mental-escher]

It's actually quite simple. After estimating the geometry of the room, feed this info into a vector mapping program (http://www.llnl.gov/graphics/docs/Viz94.pdf#search=%22velocity%20vector%20mapping%20 program%22) and then run your virtual audio signal (ie, the voices in the recording, with initial direction and velocity estimates) with various dampening levels until you match the latent audio spectrum of your original recording. Then subtract this audio spectrum and viola- echo gone.

[theperfectsong]

Thanks for all the feedback. I'm going to try some of the suggestions but it sounds like I'm stuck with what I have. The show was with an optomitrist. I had done a sample interview with him in a small examination room with carpeting and it sounded great.
When we did the real interviews, he suggested another room where we wouldn't hear patients walking around and phones ringing. I should have gone with my instincts and stuck with the first room and the ambient sounds that actually would have added to the show. One of the good things about podcasts is the ambient sounds. Yes, doctor's offices have sounds of footsteps, phones, ringing, people talking.
Thanks, all, for the help and discussion. I'll play with the suggestions and keep in mind what I've known all along -- one of the beauties of podcasting is ambient sounds that lend the sense of place and immediacy.

[TALK RADIO SHOW]

Fully carpet the walls and ceiling.