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Path: utzoo!watmath!clyde!cbosgd!ihnp4!zehntel!tektronix!tekig1!gregr
From: gregr@tekig1.UUCP (Greg Rogers)
Newsgroups: net.audio
Subject: Re: dbx vs. Dolby B/C
Message-ID: <1807@tekig1.UUCP>
Date: Tue, 4-Dec-84 03:42:34 EST
Article-I.D.: tekig1.1807
Posted: Tue Dec  4 03:42:34 1984
Date-Received: Wed, 5-Dec-84 01:00:24 EST
References: <3582@ucbvax.ARPA> <723@watdcsu.UUCP>
Reply-To: gregr@tekig1.UUCP (Greg Rogers)
Organization: Tektronix, Beaverton OR
Lines: 29
Summary: 

I don't think dBx is the "only suitable noise reduction system for tape" as
stated.  I own a dBx unit and have seldom used it because I find the breathing
very objectionable as I've indicated several times before on the net.  There
is nothing wrong with my dBx unit, this is very normal and is simply a designed
in side effect.  The dBx home units are single band, 2:1 companders.  The single
band creates a problem whenever the program material consists of narrow 
frequency band information, such as a solo instrument.  The program material is
too narrow to mask the tape noise which then rises and falls with the solo
instrument output.  This effect is simply known as breathing.  Note that 
professional compander systems like Dolby A split the frequency spectrum into
multiple bands (4 for Dolby A).  This allows the signal to rise in one band 
without allowing the noise to rise in another band.  So I am afraid for most
classical music the home dBx units are unacceptable for me.

Now the good news.  Sanyo makes (or did) a home noise reduction unit called
Sanyo Super D.  The Sanyo Plus N55 is a simultaneous record/play (4 channels)
unit that is also a 2:1 compander BUT has TWO frequency bands.  The two 
bands seem to solve most of the breathing problems of the single band units.
I wouldn't have thought of Sanyo for this type of equipment but this is a very
nice unit that is a dramatic improvement over my dBx unit.  The N55 is about
the same price as a dBx 224 (maybe $50-$100 more retail) but I'm not sure if
they are still selling them.  I can't emphasize enough how much better the
Sanyo unit is and since I got both of them I have no reason to care which
is better.  Oh the best news, I got the Sanyo unit for $35 (new) last summer
when a local high volume discount stereo store unloaded them along with other
Sanyo amps and stuff.  I don't think they even knew what they really were.

				Greg Rogers
				Tektronix