Removing slight echo with audtion - recorded in room with hard walls

[Guest]

Hi

I just downloaded a trial of Audition CS4 for windows.

I have already used it to remove a few clicks which are evident in this short (attached) PRE-audition sample.

Now I would like to go in and remove (if possible) or at least reduce the slight "echo" of the room itself.  You can hear the "echo" in this attached wav file.

I realize I might not be able to remove all of the "echo" but if I could remove some of it it would be nice.

Thanks

Rowby

[Kost7]

Approximate time span between original & copy: Plato - 1200 years, Herodotus - 1300, Aristotle - 1400,  Homer  - 500.

http://carm.org/manuscript-evidence

[SteveG_AudioMasters_]

All that site does is to support the 'Ministry of Truth' argument. For all the sites that say things like that, I can produce an equal number that say some rather more interesting things...

http://www.dailymail.co.uk/news/article-2105714/Secret-14million-Bible-Jesus-predicts-coming-Prophet...

And quite frankly, all of this is pointless to debate here, so can we stop it now, please?

[robertchapin]

As a music major, I was introduced to an amazing workshop on room tone.  The presentation was a simple voice recording that was played in a room with a slight reverb.  The recording was played over and over again, each time recorded and played back in the same room.  After about 100 iterations, the voice became music - a series of overtones.  The room absorbed certain vibrations and reflected others back.  Seems to me, an advanced custom filter could detect those overtones to cancel them out.  This is why some problems can be minimized with a simple EQ - the reverb of every room has a different resonance, and those frequencies don't always contain the full spectrum.

[SteveG_AudioMasters_]

Rooms do not reflect back anything that isn't present in the stimulus signal - which means that whatever you cancel out also comes out of that signal, which is exactly where your problem with this approach lies.

The only system I'm aware of that works on signals like this (and you don't need 100 re-recordings to achieve it) is a feedback killer. Feedback in a room with a speaker and a mic is predominently based on the greater reflection of some frequencies than others, and this builds up very quickly. Feedback killers work by putting a small real-time pitch shift on the feed to the loudspeaker, so direct reinforcement doesn't occur. And the loudspeaker is the other significant contaminent, of course - possibly more than the room in some situations. And the response errors in this (both time and frequency-dependant) build up significantly, being reinforced each time around...

So what your workshop actually showed you wasn't really about the room, I'm afraid - it was about the system being used in it, and the room was only incidental. This is because the room, unlike the speaker, won't cause frequency distortion, only temporal disturbances.

Experiments/demonstrations like this very rarely attempt to control all the variables - and in this case it may well be that they didn't even explain them all to you, I'm afraid. How do I know? Rooms and reverberation were a significant part of my Acousics Master's thesis...

[robertchapin]

Correct.  The room was reflecting back the stimulus signal, but only frequencies which resonated with the room, which also included overtones.  So it was like music.  If it was pure reflection, it would've just been noise.  So the room was acting like a sounding board - like a guitar or any other instrument.  Really cool presentation.  Sorry if you don't think so.

And I should've known to post in a thread where there are so many people willing to jump in immediately and say "no, you're wrong" without even thinking.  Oh, wait, this is the same guy who was the first to say "it can't be done"?  Should've guessed.  Dude, looking back at every single one of your posts, there is nothing that you say is even remotely positive.

I'm no "audio master", but I know that every room has its own acoustic property, regardless of what system is being used, which resonates based on specific frequencies.  Has nothing to do whether it's an amplifier or a human voice.  And I'm sure there's plenty of online sources and peer-reviewed journals to back that up.  If you want to argue anything further, you might want to cite  sources other than yourself.  And you might want to talk to people instead of talking down to them.  They tend to listen better and believe in what you say as opposed to thinking that you're just a bitter know-it-all.

[SteveG_AudioMasters_]

robertchapin wrote:

And I should've known to post in a thread where there are so many people willing to jump in immediately and say "no, you're wrong" without even thinking. 

Yes you should have. But hey, you didn't - which says quite a lot about you, really. Not only that, but you didn't even read what I said properly, or apparently understand it.

I'm no "audio master", but I know that every room has its own acoustic property, regardless of what system is being used, which resonates based on specific frequencies.  Has nothing to do whether it's an amplifier or a human voice.  And I'm sure there's plenty of online sources and peer-reviewed journals to back that up. 

And where exactly did I say that wasn't true?

And I wasn't talking down to you, or even about you. I will now though - I think it's you that needs a lesson in humility, not me.

[CRGreenDotCom]

http://dl.dropboxusercontent.com/u/3675908/echo-removal-test2.wav

[ExpoToddC]

Lol. I just thought SteveG might like to know that his helpful reputation has grown beyond the mere confines of Adobe Forums. Removing Echo from Audio with Adobe Audition