Xref: utzoo rec.music.makers:9406 rec.music.synth:14579 comp.music:1586 Path: utzoo!utstat!news-server.csri.toronto.edu!rutgers!ucsd!helios.ee.lbl.gov!nosc!logicon.com!trantor.harris-atd.com!trantor!apolivka From: apolivka@x102a.harris-atd.com (polivka al 60047) Newsgroups: rec.music.makers,rec.music.synth,comp.music Subject: dbx vs. Dolby C Noise Reduction Message-ID: Date: 15 Jul 90 14:27:45 GMT Sender: news@trantor.harris-atd.com Organization: Harris Gov't Aerospace Systems Division Lines: 43 X-Local-Date: 15 Jul 90 07:27:45 PDT Can anyone answer some or all of the following questions about Dolby C and dbx Noise Reduction systems? dbx --- 1. I understand that dbx is basically a compander. - Is the signal simply passed through a non-linear device such as a log amp, or is there a dynamic gain device such as an AGC (automatic gain control), or what? - If it uses a dynamic gain device, then: - How does the playback expander know when and by how much to expand? - Is there a separate control signal recorded that is used to dynamically adjust playback level? Dolby C ------- 1. How does Dolby C work? Comparison of the two --------------------- 1. I've seen advertised SNR's of 85 dB for dbx. What SNR performance does Dolby C achieve? 2. What are the pros and cons of Dolby C vs. dbx, particularly with respect to the application of multitrack recording? 3. The Nov '88 issue of Keyboard magazine, p147, mentions a problem with dbx having a "tendency to cut off leading edges of transient sounds, such as drum attacks and so forth." What causes this problem and how serious is it? Thanks, Al -- ------------------------------------------------------------------------ Al Polivka arpa: apolivka@x102a.ess.harris.com Mail Stop 102-4858 usenet: uunet!x102a!apolivka Harris Corporation phone: 407-729-2983 Government Aerospace Systems Div. Bldg: 102 Room: 3433 P.O. Box 94000 Melbourne, FL 32902 ------------------------------------------------------------------------