Jayelles
New Member
One of the problems with Dave's analysis seems to be that he is depending on his aural competency for analysis.
The real experts do not just rely upon what they hear (aural) but also what they see on the graphs which are produced by the specialised forensic audio equipment. These graphs are called spectrograms and they can show sounds which are inaudible to the human ear (even a trained ear). The expert that I have been in contact says the real key to forensic audio analysis is the spectrographic. Aural analysis is guided by this. He suggested to me that I should ask how Dave analysed the audio waveforms (spectrograms). Courtesy of Rainsong, Dave was asked this very question and his response was:-
Here is a link which explains why aural analysis is insufficient on its own:-
Here is a link which demoshows how the visual analysis of the graphs aids with the analysis:-
http://caeaudio.com/forensicmethod.html#audibility
Also, check out these enhancement examples. There is one which sounds a bit like the Ramsey tape:-
http://caeaudio.com/forensicmethod.html#audibility
I've read quite a few websites about this at the suggestion of my contact. On one of the websites (it might be the CAE one actually), it stressed that the client should go and hear the enhanced tape in the studio because their playback equipment was far superior to an ordinary cassette and that this made a considerable difference to the audibility!
>>I also think that there is a large difference between people's abilities to hear things. It takes some training to be able to distinguish sounds ("trained ear"). This may explain why some people seem to hear nothing at all, others hear conversation, and those of us who have at least somewhat of a trained ear can easily locate the noises but don't understand how anyone could possibly confuse these noises with conversation.
http://www.***********.com/dcf/DCForumID101/1772.html#38
The real experts do not just rely upon what they hear (aural) but also what they see on the graphs which are produced by the specialised forensic audio equipment. These graphs are called spectrograms and they can show sounds which are inaudible to the human ear (even a trained ear). The expert that I have been in contact says the real key to forensic audio analysis is the spectrographic. Aural analysis is guided by this. He suggested to me that I should ask how Dave analysed the audio waveforms (spectrograms). Courtesy of Rainsong, Dave was asked this very question and his response was:-
Rainsong,
The short answer is that my report stands on its own. I invite others to reproduce what I've done or to run their own tests and write up their results. Then we'll have something to discuss. The questions you posted are a form of cross-examination by a hostile attorney who isn't familiar with audio engineering and basic signal analysis, and isn't familiar with the spectral characteristics of voice and phone lines --- or assumes that the audience is not. I see no indication of a search for the truth here at all.
Technical issues are decided on based on technical merit, not on pedigree nor brand and cost of equipment used, etc.
http://www.***********.com/dcf/DCForumID101/1772.html#8
Here is a link which explains why aural analysis is insufficient on its own:-
"When listening to difficult to hear audio the brain will eventually impose an order to the frequencies and rhythm patterns, and may decide that something specific was said, or may assign a particular subjective interpretation."
http://caeaudio.com/illusion.html
Here is a link which demoshows how the visual analysis of the graphs aids with the analysis:-
http://caeaudio.com/forensicmethod.html#audibility
Also, check out these enhancement examples. There is one which sounds a bit like the Ramsey tape:-
http://caeaudio.com/forensicmethod.html#audibility
I've read quite a few websites about this at the suggestion of my contact. On one of the websites (it might be the CAE one actually), it stressed that the client should go and hear the enhanced tape in the studio because their playback equipment was far superior to an ordinary cassette and that this made a considerable difference to the audibility!