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On 20/12/2011 15:15, Steven Smolian wrote: > Has anyone tried using the Izotope phase correcting program on a left/right > groove transfer of a mono groove to line up both channels? > > > From what I can tell, Izotope's phase correction works at 1/100 of a bit > rather than the 1 bit as with many other programs and, I am told, makes a > noticible audible improvement on stereo tape phase issues over programs in a > similar price range. > > Steve Smolian > > > -----Original Message----- > From: Association for Recorded Sound Discussion List > [mailto:[log in to unmask]] On Behalf Of Richard L. Hess > Sent: Tuesday, December 20, 2011 9:50 AM > To: [log in to unmask] > Subject: Re: [ARSCLIST] Straight Line Tracking was Stanton Turntable > reviews....anyone? > > Hi, Don, > > The time/phase error at the stylus tip could cause significant problems if > an attempt was made to create a mono sum of the signal. It's the same thing > we see with tape azimuth. > > The 1/400,000 of a second at 78 rpm would translate to approximately 32 > degrees of electrical phase angle difference at 15 kHz at 33.3 rpm, which is > not huge, but significant. This is the order-of-magnitude of azimuth wander > seen on less-than-ideal, but not horrid 3.75 and 7.5 in/s tapes. > > But you are certainly correct that a one foot path length difference would > produce an error of a full cycle at about 1120 Hz, but somehow we don't hear > that path length difference in the same way we hear a mono sum before the > signal is fed to the speakers. > > Cheers, > > Richard > > On 2011-12-20 8:59 AM, Don Cox wrote: >> On 18/12/2011, George Brock-Nannestad wrote: >> >>>> From: Patent Tactics, George Brock-Nannestad >>>> >>>> >>>> Hello, >>>> >>>> Eric Jacobs has given a very full answer to the S- and straight >>>> arm question. >>>> >>>> However, there is one further aspect of the tangential tracking >>>> arm question and pivoted arm question that has to be kept in mind. >>>> The original derivations of the advantages and disadvantages of >>>> the various pivoted arm geometries was based on mono only, and >>>> coarse-groove dimensions. Percy Wilson pointed out a special form >>>> of time distortion: the overhang in his elaborated example meant a >>>> gradually slower reproduction because in effect the needle tip >>>> moved along the groove during play. However, he calculated that on >>>> one revolution at 78rpm the delay only amounted to 1/400,000 >>>> second. That is not discernible to a listener. However, in the >>>> stereo case, and in particular with line contact or elliptical >>>> stylii, the situation is different, and the time scale between the >>>> two channels shifts. With a slower speed and higher recorded >>>> frequencies there are definite time delay shifts between channels at > the high frequencies. >>>> >> I think this would be negligible compared to the effect of not being >> precisely equidistant from the speakers. >> I routinely use the Cedar phase program when dubbing from disc and it neatly sorts this problem out.