KnowledgeBase | K2600R | Program Mode


Portamento And Clicking Sounds

Question:
I am trying to use portamento with sample-based programs but am experiencing clicking sounds.

Answer:

Portamento is an inherently difficult thing to do on a sample playback device. This is because the unit has to bend one sample up (or down) and at some point grab the next sample from the next key range and have it bent down (or up) and then start bending it. Going from one sample to another smoothly without any noticeable artifacts is almost impossible. This is why portamento is not normally found on sample playback units. In fact, it may be different now, but when the K2000 was released, it was the only sample playback unit that could do portamento. The only solution to the problem is to lessen the transition between sample ranges.

You can reduce the number of clicks you'll hear in one of two ways:

Option 1) edit the keymap so that you have the a particular root assigned across the entire stretch of keys where you want to do your portamento. Then you will only be bending a single root instead of transitioning between two or more roots and you won't have the problem.

EditKeyMap          <>KeyRange:C 0-G 10 
MasterXpose :0ST          
Key Range   :C 0-G 10   Lo:C 0  Hi:G 10
Sample      :1  Grand Piano-C 4
Course Tune :0ST
Fine Tune   :0ct
VolumeAdjust:0.0dB
Name   Save   Delete Dump  NewRng Assign

Option 2) entering the Program Editor and adjusting the KeyTrk parameter on both the KEYMAP and PITCH pages. The quickest way is to set the KeyTrk value on the KEYMAP page to 0,

EditProg:KEYMAP            <>Layer:1/1  

KeyMap:1 Grand Piano         Stereo:Off
Xpose :0ST        TimbreShift :0ST
KeyTrk:0ct/key    PlayBackMode:Normal
VelTrk:0ct        AltControl  :OFF
SmpSkp:Auto       AltMethod   :Switched
<more  ALG    LAYER  KEYMAP PITCH  more>

...and to 100 on the PITCH page.

EditProg:PITCH            <>Layer:1/1  
Coarse:0ST         Src1  :OFF
Fine  :0ct         Depth :0ct
FineHz:0.00Hz      Src2  :OFF
KeyTrk:100ct/key   DptCtl:OFF
VelTrk:0ct         MinDpt:0ct
                   MaxDpt:0ct
<more  ALG   LAYER  KEYMAP PITCH  more>

This will stretch the sample root that plays at C 4 across the entire keyboard. Now any amount of portamento will play only one sample root, and the clicks will disappear.

There's a tradeoff here, since many sounds will change in timbre as these single sample roots are pitch-shifted during the portamento. This will be most noticeable for acoustic instrument sounds, and may not be noticeable at all for single-cycle waveforms like sawtooth waves. Furthermore, some samples will not glide all the way up to the highest notes—there's a limit to the amount of upward pitch-shifting that can be applied to samples. If this doesn't work for you, you can compromise between the number of clicks and the amount of timbre change by further adjusting the KeyTrk parameters on the KEYMAP and PITCH pages.

As long as the combined values of the KeyTrk parameters on both pages add up to 100, you'll have normal semitone intervals between keys. If you set both parameters to values of 50, for example, the sound will still play normally, and you'll have several sample roots (about half the number of the original sound) stretched evenly across the keyboard, instead of just one. This will give you fewer clicks than in the original sound, but not as much change in timbre as setting the KEYMAP KeyTrk value all the way to 0. Set the KEYMAP KeyTrk parameter higher to reduce the change in timbre, or set the PITCH KeyTrk value higher to reduce the number of clicks. Just make sure the combined values add up to 100, to preserve the normal intervals between notes.


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