M300 Owner's Manual-English - Lexicon

The Algorithms and their ParametersStereo Pitch Shift Delay and Feedback PageLDLY adjusts the length of a delay line in series with the left input. The range iszero to 510ms in 2ms steps.Pre-delay also affects the delay of any feedbackwhich is applied. In stereo mode the two pre-delays must be set to the samevalue, or the signals will not be in phase. Optimal pitch shift occurs when LDLYis about 40ms.LDLY and RDLYRDLY is the same as the LDLY, except that it acts upon the right channel.L FBK and R FBK control the amount of positive feedback from the output of thepitch shift to the input of the pre-delay line. The control is adjustable from 0 to+99%. Some very useful efects can be obtained by combining pitch shift, delay,and feedback.LFBK and R FBKBNPS is a band-pass filter which rolls off the frequency responce of the audiobefore the splicing algorithm. The -3dB point is 100 Hz. The purpose of the bandpassfilter is to give the pitch shifter less information than it actually needs todecide when to make the splice. Typically, this will inprove the performance ofthe pitch shifter.BNPSSYNC is only active in STEREO mode. This control forces an exact sync of thetwo channels when the control is turned from 0 to 1. When SYNC is 1, there isan automatic re-syncing any time the two channels differ in phase by about 10samples. This can occur if PCHL or LDLY is changed. Re-syncing can cause asmall click in the output. If the pitch shifter is being used to manually pitch-correctclassical music using the GLDL control, it may be better to set SYNC to 0, or Off.There is an automatic sync tracking feature which will keep the two channelslocked to within 2 samples. If precise synchronization is desired, the GLDL orPCHL controls should be set, SYNC should be set from 0 to 1, and then the pitchshould not be changed. The two channels will remain precisely synchronized,even though both are continually changing the splice length in response to theincoming pitches.SYNC4-17