Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site watcgl.UUCP Path: utzoo!watmath!watcgl!dmmartindale From: dmmartindale@watcgl.UUCP (Dave Martindale) Newsgroups: net.audio Subject: Re: Bias Adjustment in Cassette Decks Message-ID: <2295@watcgl.UUCP> Date: Thu, 22-Mar-84 13:27:36 EST Article-I.D.: watcgl.2295 Posted: Thu Mar 22 13:27:36 1984 Date-Received: Fri, 23-Mar-84 08:13:57 EST References: <6062@umcp-cs.UUCP> Organization: U of Waterloo, Ontario Lines: 25 When adjusting bias by ear, I would say do it with Dolby off. There are three adjustments (at least) that must be made to adjust a deck properly for a particular tape formulation: bias, record EQ, and record level. With a user-adjustable bias control, you can get only one of those, so results won't be ideal. If the record level is misadjusted, you will inevitably get Dolby mistracking, as the Dolby circuits will read the same signal as being at different levels on record and playback, and apply differing amounts of high-frequency boost/compression. With Dolby switched off, at least you will be dealing with only bias-related frequency response changes. Note that setting bias by perceived frequency response won't get you the best possible bias either, unless the record EQ just happens to be correct for that tape. The normal procedure for setting up a deck in the shop seems to be to set the bias to produce some specified level of distortion (that the manufacturer has found to produce the best tradeoff of various problems), then set the record EQ so the frequency response is flat, and then set the record level so that a given signal level into the tape will produce the same level coming off, as seen by the level meters and Dolby circuitry. Without setting all three, you just won't get the best the deck is capable of. Is recording on many different varieties of tape that important?