Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!cbosgd!cwruecmp!neoucom!wtm From: wtm@neoucom.UUCP Newsgroups: sci.electronics Subject: 3800 Hz notch filter [will] be used on CD masters Message-ID: <598@neoucom.UUCP> Date: Fri, 5-Jun-87 14:02:01 EDT Article-I.D.: neoucom.598 Posted: Fri Jun 5 14:02:01 1987 Date-Received: Sun, 7-Jun-87 19:48:55 EDT Organization: Northeastern Ohio Universities College of Medicine Lines: 56 Keywords: with possible icky results! Hi, I just heard from some people that got back from the Chicago CES, some of the details of the proposed new standard to be employed for production of source material (compact disc records) and digital audio tape (DAT) machines. From my understanding, what will possibly be done is to master CDs with a narrow band notch set for 3800 Hz as the material is mixed down into final form for the consumer's copy. DAT machines are to be equipped with a so-called spoiler chip that will monitor three narrow bands of 3800-, 3800, and 3800+ Hz. The idea is that if the chip detects energy in the two outer bands and none in the middle band, that it will shut down the recorder, as "obviously" a pirating event would be under way. The question for the net is, just how wide is the missing mateial notch going to be. Supposedly, people that have heard trial recordings of the processed material claim that it is very noticable on things like classical and jazz recordings that feature solo instrument passages more than rock does. Apparently, some notes are curiously dull sounding on piano passages due to the action of the notch filter. Vocals are also apparently affected. The record companies are currently lobbying the US congress to enact legislation that would make the use of the spoiler chip mandatory on DAT machines sold in the US. Columbia Records announced that it is going to start processing all its releases in the next few months to have to 3800 Hz notch. Other record companies have not officailly announced any plans. Marantz plans to begin importing in September of '87, a DAT machine that *will not* have a spoiler circuit. They are operating under the assumption that the legislature won't be able to do anything before then any way. The whole DAT spoiler seems silly to me. The wost thing is that people who do not pirate the material are punished by having to listen to recordings of reduced quality. It would be possible for pirates to go about their business by summing low level hiss with a spectrum centered at 3800 Hz. I suppose that a correlation could be done to see if the amplitude of the 3800 component related to the sidebands, thus preventing hiss injection from spoiling the spoiler, but that sort of DSP would probably be too expensive for consumer equipment. There is something you can do. The recording rights coalition has a phone number, 800-282-TAPE, that you can call to get information about where you can complain about the proposed spoiler legislation. Bill Mayhew Division of Basic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272 USA phone: 216-325-2511 (wtm@neoucom.UUCP ...!cbatt!neoucom!wtm)