Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!sun-barr!lll-winken!aunro!alberta!cpsc.ucalgary.ca!yogi.fhhosp.ab.ca!janus.mtroyal.ab.ca!ewilts From: ewilts@janus.mtroyal.ab.ca (Ed Wilts) Newsgroups: comp.sys.amiga.audio Subject: Re: Re:Perfectsound Message-ID: <1991May14.142330.8211@janus.mtroyal.ab.ca> Date: 14 May 91 20:23:30 GMT References: <1991May13.022242.13462@magnus.acs.ohio-state.edu> Organization: BC Systems Corporation, Victoria, B.C. Lines: 32 In article , othomas@athena.mit.edu (Oliver J. Thomas) writes: > In article <1991May13.022242.13462@magnus.acs.ohio-state.edu> mdoerner@magnus.acs.ohio-state.edu (Mike R Doerner) writes: > >> 2.) Is it possible to take "fuzzy" & "hissy" studio recordings >> and have them re-recorded as "clean" without the hissing & fuzz (in >> other words, recording w/o dolby equipment & cleaning it up.) > > This is a little more tricky. Basically, to clean up a signal, what is usually > done is filtering (digital or analog) out those frequencies where you suspect > most noise to be concentrated, and, in some cases, convolving the waveform by > a smoothing function to take out the "hard edges" associated with noise. > > Now, to do this filtering on the Amiga, the basic procedure would involve > transforming the incoming signal into the Frequency Domain (through Fast > Fourier Transforms, usually), multiply that by the appropriate filter > function, and by a smoothing function, the reverse transform it to get a time > signal back, which is the cleaned up audio. Sounds simple enough, and the > algorithms aren't that hard, but don't expect your Amiga to do it in real > time. If you just want to clean up recordings, though, real time should not be > an issue. Check out a product called Studio Magic, also from Sunrize. It lets you do all sorts of manipulating of the samples, including FFTs. It will generate 3D graphics of the samples, as well as do some basic editing kind of things like cut & paste, echo, etc. > Oliver Thomas > othomas@athena.mit.edu -- .../Ed Preferrred: Ed.Wilts@BSC.Galaxy.BCSystems.Gov.BC.CA Ed Wilts Alternate: EdWilts@BCSC02.BITNET (604) 389-3430 B.C. Systems Corp., 4000 Seymour Place, Victoria, B.C., Canada, V8X 4S8