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Forensics examiners are often confronted with the problem of authenticating a recording. Often, these recordings are of the Microcassette variety. At issue is the question of whether or not the tape has been edited or modified in some way. Often, tapes are edited on a different machine from their original recording device. If a different machine was used to edit the tape, and since each machine leaves its own distinctive stop / start pattern when viewed in the time domain (display), it can be determined if the start / stop breaks were all made on one machine or two or more.
But, often the examiner is confronted with hours of tape and needs to focus in on the start / stop sequences rather than sitting through the entire tape(s) looking for these interruptions.
The attached multifilter preset will provide a way to Mark the file where these breaks occur so that a close examination of the file can be made in the time domain display without listening to the entire file(s) to look for recorder erase / record head signatures on the recording.
There are two methods that one can use to operate this Multifilter Preset.
Method 1:
This method is the easiest to use, but is not self-documenting. In Classic Edit mode, run the attached preset on the Source file with the system (View Menu) set for Sync mode. Each start / stop sequence will be identifed by a very large rail to rail pulse which shows up in the destination display. You can then zoom-in on the various start / stop events.
Method 2:
This method is a bit more complicated to use, but it is self documenting (meaning that the audio material and the markers are integrated into the same wavefile).
1. Use the File Converter Filter to make a Stereo File out of the Mono one that you have from the Microcassette recording.
2. Make the Destination the Source.
3. Clone the File.
4. Run the attached multifilter on either the Left or Right Channel only.
Results: You will see a large pulse appearing on one channel wherever there is a Microcassette start / stop sequence. The pulse should be clear and obvious and rail to rail.
Let us know if this preset is helpful to you.
Thanks,
Craig
Important Note: This preset is only compatible with the Forensic Version of the Diamond Cut software.
keywords: Forensics Tape Authentication, Tape Splicing, Tape Editing, Evidence Tampering Detection, Tape Integrity Detection
But, often the examiner is confronted with hours of tape and needs to focus in on the start / stop sequences rather than sitting through the entire tape(s) looking for these interruptions.
The attached multifilter preset will provide a way to Mark the file where these breaks occur so that a close examination of the file can be made in the time domain display without listening to the entire file(s) to look for recorder erase / record head signatures on the recording.
There are two methods that one can use to operate this Multifilter Preset.
Method 1:
This method is the easiest to use, but is not self-documenting. In Classic Edit mode, run the attached preset on the Source file with the system (View Menu) set for Sync mode. Each start / stop sequence will be identifed by a very large rail to rail pulse which shows up in the destination display. You can then zoom-in on the various start / stop events.
Method 2:
This method is a bit more complicated to use, but it is self documenting (meaning that the audio material and the markers are integrated into the same wavefile).
1. Use the File Converter Filter to make a Stereo File out of the Mono one that you have from the Microcassette recording.
2. Make the Destination the Source.
3. Clone the File.
4. Run the attached multifilter on either the Left or Right Channel only.
Results: You will see a large pulse appearing on one channel wherever there is a Microcassette start / stop sequence. The pulse should be clear and obvious and rail to rail.
Let us know if this preset is helpful to you.
Thanks,
Craig
Important Note: This preset is only compatible with the Forensic Version of the Diamond Cut software.
keywords: Forensics Tape Authentication, Tape Splicing, Tape Editing, Evidence Tampering Detection, Tape Integrity Detection