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

May 28, 2009 5:00 AM

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

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  • SteveG(AudioMasters)
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    May 28, 2009 3:50 PM   in reply to rowby

    rowby wrote:

     

    I just downloaded a trial of Audition CS4 for windows.

    No such animal - Audition is emphatically not part of the CS suite. It used to be, and that was a right pain. Fortunately for all of us it was removed from it a while back, after AA2.0 was prematurely released. Since this was a direct result of a release date determined only by marketing, it was hardly surprising, really...

     

    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.

    Sorry, no chance. It's like trying to unbake a cake; you simply can't do it. Especially in this case where it's a short reverb, and it inevitably contains only the same frequencies that you want to keep. (This is a reminder to anybody about to suggest EQ, like they usually do, that it can only possibly make things worse, like it always does...).

     

    You are stuck completely with this - no software on earth can get rid of that sort of problem. You have to take rather more care with the recording in the first place to prevent this, I'm afraid. That's why people use treated studios for anything serious - just to get over problems of this nature.

     

    The only exception to this in any way is that if you have a stereo recording where the echo is in the stereo field rather than the summed mono one, you can use the Audition Center Channel Extractor, and effectively extract just the wanted mono part. But with a mono recording (which contains no vector information at all) you simply can't do this.

     
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    May 28, 2009 3:19 PM   in reply to rowby

    For what it's worth, there are deconvolution techniques that are effective at echo removal, but they mostly apply to simple cases, such as telephony, where the echo is a simple time-delayed copy of the original signal.  Such methods applied to natural reverberance most often make things worse.  For now, and probably well into the future, there's no good substitute for controlling the recording environment.

     
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  • SteveG(AudioMasters)
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    May 28, 2009 3:53 PM   in reply to AskMrScience

    AskMrScience wrote:

     

    For what it's worth, there are deconvolution techniques that are effective at echo removal, but they mostly apply to simple cases, such as telephony, where the echo is a simple time-delayed copy of the original signal.

    I've altered the reply above to say 'reverb' - as what's in the sample doesn't begin to qualify as an echo. It's what I meant to say in the first place, but it got overlooked in the reply process.

     
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    May 29, 2009 9:50 PM   in reply to rowby

    I deal with this all the time

     

    use the Graphic EQ

     

    you can't kill everything but a great deal can be removed just by adjusting the bands

     

    here's the settings I used with just a quick pass

    and I've posted the modified file I reversed the name to avoid overwriting the original

    load them both and compare

     

    EQ is fine for speech audio but not the best idea for trying to fix music

    EQ30Band.PNG

     

    Message was edited by: Richard FDisk

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  • SteveG(AudioMasters)
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    May 30, 2009 6:59 AM   in reply to Richard FDisk

    Richard FDisk wrote:

     

    I deal with this all the time

     

    use the Graphic EQ

     

    you can't kill everything but a great deal can be removed just by adjusting the bands

     

    You clearly didn't read or understand my first post. You have killed nothing, and removed signal at the same rate as reverb - which makes it harder to hear the content and almost certainly makes things worse, not better. This is a complete waste of time.

     

    *update* I've now listened to what you did, and it conforms absolutely to what I just said - you've made the intelligability significantly worse, not better, and all the room sound is still there.

     

    THERE IS NO FIX FOR THIS.

     
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    May 31, 2009 8:44 AM   in reply to SteveG(AudioMasters)

    why do you attack me?

     

    ► it actually turned out not too bad oy my system,

     

    ► the "echo" is just re-amplification & recording of certain wave lengths that happen to make it back to the mic, by reducing those signals it's less "tinny" or "echoey"

     

    ► if EQ is a useless tool why include it in AA?

     

    ► the OP asked to reduce the problem not remove it completely,

     

    ► yes the "room sounds" are still there, but not as distracting or "IRRITATING" as when "untouched"

     

    ► the average joe listening to any recording doesn't listen with an Audio Engineer's Ear, why do you think that mp3's and other forms of lossy compressed garbage are so popular?

     

    ► yes you can't "Unbake" a cake, but you can make a bad cake more paletable with a little bit of "bakers touch"

     

    ► sorry I tried to help

     

    Message was edited by: Richard FDisk

     
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    May 31, 2009 9:51 AM   in reply to Richard FDisk

    Richard FDisk wrote:

     

    why do you attack me?

    Steve is not attacking you.  He's attacking the assertion that EQ can get rid of early reflections in a recording of this type.  We've had many discussions in the past over this very thing.

     

    ► it actually turned out not too bad oy my system,

     

    ► the "echo" is just re-amplification & recording of certain wave lengths that happen to make it back to the mic, by reducing those signals it's less "tinny" or "echoey"

    Well the waveform you posted sounds really bad on my system.  It sounds like someone is running lines in a living room and you just happened to record them from the other side of the room.  These early reflections are not just a collection of "certain" wavelengths that "happen" to make it back to the mic.  They are reflections of virtually the entire frequency spectrum of the voice of the person speaking.  EQ cannot fix this and make the early reflections less prominent.  Your waveform confirms this.  The early reflections are still there in your recording and still very prominent.

    When using EQ in an attempt to lessen this problem, one cannot escape the fact that any EQ changes affect everything on the recording, not just the early reflections.  Since the early reflections are generated by the person's speaking voice, they are in the same frequency range as that voice, so when you are using EQ to lessen the early reflections the EQ is also affecting the person's speaking voice, which isn't desirable at all.

    ► the average joe listening to any recording doesn't listen with an Audio Engineer's Ear, why do you think that mp3's and other forms of lossy compressed garbage are so popular?

    Delivery systems of audio have nothing to do with poor recordings.  Poor recordings will sound poor regardless of the final format for listening.  The average joe will be able to tell the difference when presented with a 128kbps .mp3 of two different recordings of a voice over, one done in a proper studio with a voice over booth and one done in an untreated living room.  That's why a lot of money is spent to create recording rooms in studios.  If it were simply a matter of fixing room reflections will EQ then studios wouldn't spend the money for recording rooms.

     

    The only real way to correct the problem of early reflections in a room is to treat the room in some manner.  One of the inexpensive ways to cut down on early reflections is to get some extra mic stands with booms, hang some cheap packing blankets from the mic stands and set these around the voice talent (raising the mic stand height well above the head of the voice talent).

     
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  • SteveG(AudioMasters)
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    May 31, 2009 3:51 PM   in reply to Richard FDisk

    ► it actually turned out not too bad oy my system,

     

    ► the "echo" is just re-amplification & recording of certain wave lengths that happen to make it back to the mic, by reducing those signals it's less "tinny" or "echoey"

     

    ► if EQ is a useless tool why include it in AA?

     

    1) Your system is clearly incapable of reproducing accurately what you are doing - or you can't hear it.

     

    2) That is a complete non sequitur - you haven't reduced the relative amplitude of those signals at all.

     

    3) I never said it was useless for all purposes - I only suggested that it's useless for this purpose.

     

    ► yes you can't "Unbake" a cake, but you can make a bad cake more paletable with a little bit of "bakers touch"

     

    ► sorry I tried to help

    1) Once you've made a bad cake, nothing improves it - if the cooked ingredients taste bad, they stay that way.

     

    2) You have to learn a few things about 'helping'. The very first one is to read what's already in the thread, and unless you have a very good reason for flatly contradicting what's there, then don't. And if you wish to contradict anything, then say precisely why. Otherwise, you are doing anything but helping.

     

    Other than that, read what Eric said.

     
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    Jun 2, 2009 9:14 AM   in reply to rowby

    Adding reverb in an attempt to remove it?  You'd be adding a new layer of reverb to the existing unwanted reverberance was well as to the signal that you're trying to isolate.  It quickly becomes a hall of mirrors - and phase shifts.

     
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  • SteveG(AudioMasters)
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    Jun 2, 2009 12:10 PM   in reply to rowby

    rowby wrote:

     

    There is no success guarantee!"

     

    Any thoughts about this approach?

    Indeed - I can guarantee no success!

     

    If you want to read a sensible explanation of why this won't ever work, then I can refer you to the old FAQ about this that used to be on this forum, but is now only available (like all of the rest) on AudioMasters. It's here.

     
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    Jan 29, 2013 1:14 PM   in reply to SteveG(AudioMasters)

    Just read this and man your an *******.  He was just trying to help. 

     
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  • SteveG(AudioMasters)
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    Jan 29, 2013 2:52 PM   in reply to SammyT303

    And thank you for your helpful, useful comment. Just what we all needed.

     
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    Mar 6, 2013 12:55 PM   in reply to SammyT303

    I agree! If the poster disagreed with the person's solution there is a more tactful way of handling the response.  Obviously, a decent time was spent on the response (a screenshot and audio file were included).  I mean, even if you hate it, you handle the situation better than that.

     
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  • SteveG(AudioMasters)
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    Mar 6, 2013 2:01 PM   in reply to mikemclin

    mikemclin wrote:

     

    I agree! If the poster disagreed with the person's solution there is a more tactful way of handling the response.  Obviously, a decent time was spent on the response (a screenshot and audio file were included).  I mean, even if you hate it, you handle the situation better than that.

    Well, if that's your idea of 'handling a situation better'...

     

    So let me tell you. I spent years doing research into reverberation in spaces for a Master's Degree, not just a couple of minutes posting a screenshot of something that doesn't work. So don't talk to me about 'a decent time' - you have no idea.

     

    There's one plugin called UNVEIL that's supposed to be able to mask out some reverb effects. I tried the 'fully functioning' demo on a nice clean 5 second reverb, nicely delineated. What did I end up with? 5 seconds of reverb. And for the priviledge of achieving this result with their software, you pay $399.

     
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    Mar 6, 2013 8:21 PM   in reply to SteveG(AudioMasters)

    I have to ask...was it really worth resurrecting a four year old thread just to make a personal attack and swear at somebody who, after all, was correct?

     

    Sometimes an idea is simply a bad one that won't/can't work.  Does it really benefit anyone to sugar coat the answer and pretend it's worth further consideration?  You're entitled to your own opinion on that question.

     

    However, on the original question of whether it was worth re-opening a four year old thread simply to attack somebody, there's no debate.  It was simply an exercise in excrement stirring.

     
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    Mar 14, 2013 12:43 PM   in reply to Bob Howes

    I have Audition CS6, but haven't used it very much.  Recording from a telephone, I have an echo of my voice,  significantly lower in volume, about 5 to7 seconds later   I see there's a lot of heat about the ability to eliminate this kind of thing, but being new to this forum, would like to raise it again, without the metaphors or posturing. 

     

    I suppose I could go through the wave form, locate the echo and eliminate it, but that would be quite time consuming. 

     

    Any positive ideas would be much appreciated.

     

    Thanks in advance.

     
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    Mar 14, 2013 4:07 PM   in reply to rmartin215

    Unfortunately it has all been said further back in this thread. There is no easy way of removing echo or reverb. There is one slight chance but it would rely on the echo being very precisely constant time away from your original. You could try copy and mix pasting your full level audio delayed by the exact time over the echoes to cancel them out. I have a feeling that this probably won't work because the delay time of the echo may be variable throughout the piece.

     
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    Mar 14, 2013 4:42 PM   in reply to rmartin215

    I'm curious about the interval.  If it's as long as 5 - 7 seconds, is this by chance a tape recording?  Sounds like a case of magnetic print-though.  In any case, I just did a quick web search on "echo cancellation", and there does appear to be deconvolution software out there, meant for things like Skype, that may hold promise.  I haven't used any of them, so I can't report any first hand experiences.  Within Audition, no, I can't think of anything except perhaps noise gating.  Good luck!

     
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    Mar 14, 2013 7:52 PM   in reply to rmartin215

    I must say that 5-7 seconds sounds long even for a phone line.  Are you sure you're not being bugged? 

     

    In any case, the sort of echo you get on a phone is very different from the room reverb that was being talked about before and you may have a slightly better chance.

     

    If it was me, I'd probably try using a gate, carefully set to allow the "main" voice through but closing for the echo level.  I'm not usually a fan of using a gate for most noise control but on an echoey phone it can work okay.

     

    Failing being able to get a gate to work, I'd just make a cup of tea and sit down with the file, muting the echo manually (which is, in effect, becoming a tea powered gate with automatically variable threshold control).  Or, you might end up with a gate setting that gets most of it with only a few leftovers to attack manually.

     
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    Mar 14, 2013 8:46 PM   in reply to Bob Howes

    Thanks to everybody for a quick reply. I'll try everything that I can.  Since the audio is only 13 minutes long, I will go thru it manually.

     

    The call was from India.  I think it had something to do with that, because local calls have no echo.

     

    Thanks again.

     
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    Mar 14, 2013 9:31 PM   in reply to rmartin215

    Almost certainly because it was from India and transmitted via satellite.  Assuming you are in the US, that's a minimum of 2 satellite hops to get from India to the US and two more to get back.  Each hop is about 2/3 of a second delay so the time could add up quite quickly.

     
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    Jun 3, 2013 11:39 AM   in reply to rowby

    This plug-in does the so-called "impossible" quite well: http://www.zynaptiq.com/unveil/

     

    It's pricey, but if it saves even one session, it can be worth it.

     
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  • SteveG(AudioMasters)
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    Jun 3, 2013 3:36 PM   in reply to Joe12south

    Joe12south wrote:

     

    This plug-in does the so-called "impossible" quite well: http://www.zynaptiq.com/unveil/

     

    It's pricey, but if it saves even one session, it can be worth it.

    Yeah, we did that one a while back in this thread... and it's not that good.

     
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    Jun 3, 2013 4:15 PM   in reply to SteveG(AudioMasters)

    It's not magic in the way Jesus is, but it does work well in a lot of cases. I just hate when people say something is carte blanche "impossible."

     
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  • SteveG(AudioMasters)
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    Jun 4, 2013 1:37 AM   in reply to Joe12south

    Joe12south wrote:

     

    It's not magic in the way Jesus is, but it does work well in a lot of cases. I just hate when people say something is carte blanche "impossible."

    Well, the acoustician in me says it is. The best you can ever manage is to disguise reverberation somewhat, by reducing the tails - perhaps... You can't get rid of the early reflection signal at all; the actual 'sound' you end up with remains coloured the way it is in the original, and that's part of the reverberation that you are absolutely stuck with - period. You might get away with doing some treatment on speech, and hiding some of the decorrelated room sound, but on music signals with clearly delineated reverberation, Unveil simply doesn't work at all. They claim that it works at least in part by using a masking process, and that shows - you get results akin to a low bit rate MP3!

     

    Oh, and Jesus wasn't magic either. he's just been very badly reported by people who wrote about him 50-odd years after the event, and all the other reports that conflicted the four we generally get got 'hidden' by the local Ministry of Truth some time after the event.

     
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    Jun 4, 2013 11:47 AM   in reply to SammyT303

    SammyT303 wrote:

     

    Just read this and man your an *******.  He was just trying to help.

     

    I'm not sure who Sammy was addressing, but now I see everyone else has dogpiled on this to say how stupid it is to dredge up a 4-year-old thread to act like... a 4-year-old.

     

    Steve, adding your opinion about religious matters as fact does not add credibility to your reliable, scientifically-based assertions.  Just sayin, friend.

     
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    Jun 4, 2013 7:43 PM   in reply to MusicConductor

    Much as I agree with SteveG's comments on religion, I guess it might have been inappropriate to bring them into these U2U forums.

     

    However, I'd point out that it was joe12south who brought Jesus into things in the first place.

     
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    Jun 4, 2013 8:02 PM   in reply to Bob Howes

    Actually, I was making a sideways reference to a Sarah Silverman joke. :-)

     

    Regardless, it is possible to improve recordings, at least somewhat, with reverb baked-in. There are several tools and techniques to salvage otherwise unusable clips, and it's good that people know that.

     
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    Jun 4, 2013 11:34 PM   in reply to Joe12south

    Much as I'd love a product that could eliminate early reflections, despite what you say I've yet to hear one that did what it said on the box.  In my experience, usually it sounds worse after processing, particularly in terms of intelligibility, rather than better.

     

    Maybe someday there will be an ultra-clever software solution but none of the simple stuff mentioned (like EQ) does anything other than mess up your sound.  Like SteveG, I hate inexperienced people being mislead by well-meaning people with bad advice.

     
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  • SteveG(AudioMasters)
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    Jun 5, 2013 1:32 AM   in reply to MusicConductor

    MusicConductor wrote:

     

    Steve, adding your opinion about religious matters as fact does not add credibility to your reliable, scientifically-based assertions.  Just sayin, friend.

    The whole point is that it wasn't an opinion. What I said was only based on facts subsequently established by scholars. And I didn't mention the guy in the first place...

     
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    Jun 5, 2013 5:18 AM   in reply to Bob Howes

    The product I mentioned does an admirable job in certain situations. The trick of extracting a center channel from a stereo mic does a good job with vocal recordings...there are options for "rescuing" clips that otherwise might be unusable. Perfect? No. Better? Certainly. The OP wasn't looking for perfection...heck, the recording wasn't that great in a lot of other respects...he just needed to salvage it. We can argue academic "impossibility" or we can try to offer real-world help.

     
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    Jun 5, 2013 7:33 AM   in reply to SteveG(AudioMasters)

    The whole point is that it wasn't an opinion. What I said was only based on facts subsequently established by scholars. And I didn't mention the guy in the first place...

    I know you didn't, and I also know you've seen more than your share of the wretched affects of the abuse of religion, a damnable and very un-Christian problem (regardless of what "label" the religiosity has).  However, "scholars" can be depended on to "prove" most anything, and there is massively much evidence to the contrary for me and many others to agree with yours.  We may have to agree to disagree on this one...

     
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  • SteveG(AudioMasters)
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    Jun 5, 2013 12:11 PM   in reply to MusicConductor

    Starts OT, but gets back on track:

     

    MusicConductor wrote:

     

    However, "scholars" can be depended on to "prove" most anything, and there is massively much evidence to the contrary for me and many others to agree with yours.  We may have to agree to disagree on this one...

    Firstly it's not mine, it's theirs, although I know a present-day one. FWIW, she would be massively more inclined to your point of view than mine, I have to say. And, the physical evidence of what appears to be scholarly abuse approximately a couple of thousand years ago has disturbed her somewhat...

     

    Where's the parallel? We appear to have software where the claims about it can be 'interpreted', and indeed have been. As with all of these things, there are some Laws of Physics involved, and you ignore them at your peril. All I am doing is trying to be objective - as scientists (and scholars...) really should strive to be.

     

    And as for 'impossible' - which was the basic problem this time around - well, some things pretty much will be until some of the Laws of Physics get changed, I'm afraid. The problem with reverberation is that of reconstructing a wavefront at the point it was launched, and removing everything else that happens to it between the source and where it's being received. One very major problem with this is that although the radiated waveform is essentially from a point source (therefore spherical) in the room, by the time it gets to the microphone the angle of the sphere and therefore the shape of the wavefront has altered considerably. The physics behind this is complex; suffice it to say that even with really posh equipment, you can't easily calculate what even the launch wavefront looked like with any accuracy at all - and that's without even considering the impact that every reflecting surface in the room is adding to it.

     

    Whatever you get from 'reverb removal' is going to be fakery for the forseeable future, I'm afraid.

     
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    Jun 5, 2013 9:06 PM   in reply to SteveG(AudioMasters)

     

     

    he's just been very badly reported by people who wrote about him 50-odd years after the event

    50 years after event? It's still way better than other non-religious ancient manuscripts which no one doubts somehow today.

     
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  • SteveG(AudioMasters)
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    Jun 6, 2013 1:35 AM   in reply to Kost7

    Kost7 wrote:

     

    50 years after event? It's still way better than other non-religious ancient manuscripts which no one doubts somehow today.

    Can you provide an example, please?

     
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    Jun 6, 2013 9:13 AM   in reply to SteveG(AudioMasters)

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

    http://carm.org/manuscript-evidence

     
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  • SteveG(AudioMasters)
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    Jun 6, 2013 10:50 AM   in reply to Kost7

    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-Muhammad-unearthed-Turkey.html

     

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

     
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