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DCart has some forensics filters, and just a few days ago I received a letter informing me that they were sponsoring a forensics audio seminar. You might find more at www.tracertek.com or www.enhancedaudio.com or www.diamondcut.com Joe Salerno Video Works! Is it working for you? PO Box 273405 - Houston TX 77277-3405 http://joe.salerno.com ----- Original Message ----- From: "Paul T. Jackson" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, April 17, 2003 12:46 AM Subject: [ARSCLIST] Heavily distorted signal > I've lost the original post, but has anyone used audio forensic software? > Here is one outfit and there is at least one other in Europe: > http://www.intdevices.com/ > > Paul T. Jackson - Trescott Research > Information Resources and Library Development > [log in to unmask] <mailto:[log in to unmask]> > http://www.bookbay.com/PioneersInBrass.htm > > > -----Original Message----- > From: Association for Recorded Sound Discussion List > [mailto:[log in to unmask]]On Behalf Of Mike Richter > Sent: Wednesday, April 16, 2003 11:50 AM > Subject: > > > Subject: Re: [ARSCLIST] Heavily distorted signal > Comments: To: Association for Recorded Sound Discussion List > <[log in to unmask]> > To: [log in to unmask] > In-Reply-To: <[email protected]> > X-Server: High Performance Mail Server - http://surgemail.com > X-Smite-CRC: > A#1nGKQX6$1a8yLaQ$n1yIYv#HNsbFH#kZcu02#1yIj62W#1CA6gmw#1hE5y6s$1JS693y > > At 11:36 AM 4/16/2003 -0500, Peoples, Curtis wrote: > >I have a copy of some Turkish folk poets speaking with and without > >music. The original analog tape is very distorted. Are there any tricks > >or techniques to make the voice sound clearer. Is there a certain > >frequency range I can work with for distortion? Are there any software > >programs or outboard gear to remedy this problem? Any advice is > >appreciated. > > For some reason, two replies arrived at my in box before this original > message. > > You should play with equalization (which may vary from speaker to speaker) > to optimize retrieval. Frequently in live recording, subsonic and low > frequencies are excessive and overload the electronics. You cannot correct > for the recording overload, but you can reduce the playback effects by > judicious filtering. Experiment for your material; I often use a > fourth-order filter at about 150 Hz. > > The highs may be loaded with distortion further reducing intelligibility > but the formants are important. For a male speaking voice, try about a 6 db > boost from 1-2 KHz followed by a 3 db per octave rolloff. You may want to > move it up a half octave for female voices, but again the best > intelligibility will depend on the faults of the original and the timbre of > the speaker. > > Most denoising (I've not used the Sonic Foundry plugins) will be > ineffective at low settings and objectionable for artifacts (metallic > sound, audible echo) when set high enough to be useful. Analogue > autocorrelation has proved more effective for me than digital, so I > occasionally pull out an ancient Phase Linear autocorrelator for really > noisy sources. > > If you have a short sample for me to try digitally, please contact me > off-list. > > > Mike > [log in to unmask] > http://www.mrichter.com/