Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site hou4b.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!houxm!vax135!ariel!hou4b!mat From: mat@hou4b.UUCP (Mark Terribile) Newsgroups: net.audio Subject: Re: Are DNR noise reducers sold commercially? Message-ID: <1351@hou4b.UUCP> Date: Sun, 10-Mar-85 01:04:44 EST Article-I.D.: hou4b.1351 Posted: Sun Mar 10 01:04:44 1985 Date-Received: Tue, 12-Mar-85 03:34:04 EST References: <494@hou2e.UUCP>, <236@ihlpg.UUCP> Organization: AT&T Information Systems Laboratories, Holmdel, NJ Lines: 39 >> >> has anyone one the net heard a DNR unit operate? i would be very >> interested in opinions ! >> >Don't expect miracles from DNR. The system will make a difference >when listening to inherently noisy sources like old 78's, AM radio, ... >The amount of noise reduction is pot-adjustable, but the more noise >you cut out, the more of your highs you lose. However, the effect >is much better than what you get by using a simple lowpass filter > ... Unfortunately, any treble information recorded near or below the noise >level is lost, although your ear can normally distinguish it from the >surrounding noise (the cocktail party effect). > Bob Fishell Well, Carver claims that the autocorrelator on his top-of-the-line preamp uses a bank of comb filters, designed so that a significant signal in the midrange or lower treble will open the gates on all of the areas where harmonics are likely to appear. I believe it's true, since I once (and only once) heard mine fooled by an old piano recording (Schnabel, if that matters) which had a passage of notes in rather chromatic clusters ranging up and down the second and third octaves from the top of the keyboard. You could hear the noise following the music and (apparently) its harmonics up and down the scale. I don't believe that Carver sells the autocorrelator seperately (and if he did, it would cost a bundle) but a less sophisticated unit that he designed was sold some years back by Phase Linear (Carver's first venture). I don't know how it compares to the one I've got -- it is supposed to be a little more noticeable in operation -- or whether it's still available. Might be something to look at, though. Also, the Feb AUDIO magazine had an article about a DNR box available in kits of various sophistication, from just the semiconductors (about $35) to a complete kit with a silk-screened cabinet for about $120. -- from Mole End Mark Terribile (scrape .. dig ) hou4b!mat ,.. .,, ,,, ..,***_*.