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I'm trying to make a smooth pitch bend down 5 semi tones or so.

I have Melodyne and was trying it with that.

I was also trying to do it using the built in Pitch Shift plug-in via the automation window. I have to choose either semitones or cents.

I can't get the desired effect with semitones because it jumps too fast, and with cents, the range is not available to go multiple semitones.

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2 Answers 2

It is possible to do a smooth pitch bend with Logic and the Pitch Shifter II plugin, but it isn't easy. The core problem is that Logic is built around MIDI, and most MIDI messages are 7-bit. A 7-bit number can represent any of 127 different values, which isn't very many when you are dealing with pitch bends.

Fortunately, Logic does support a special kind of MIDI message - the 14 bit CC message. 14 bit messages are actually two 7-bit messages sent one after the other. The first message contains the first, and the second contains the second 7 bits.

If you were dealing with MIDI hardware, it wouldn't be too difficult to figure out how to do the routing. Since you are dealing with Logic plugins, you need some additional magic, which is described in this Blue Cat Audio tutorial. We won't be using any Blue Cat plugins for this, but this is the only place I've seen instructions on how to control Logic plugins from the environment.

Here are the step-by-step instructions:

  1. Open up your Logic project that has an audio track. Make sure the Pitch Shifter II plugin is inserted into that track in the TOP slot in the inserts list. Per the Blue Cat tutorial, that will assign the Pitch Shifter II to channel 2.
  2. Open the Logic Environment: Window | Environment
  3. You should be in the Mixer view in the Environment window. If you aren't, use the dropdown in the upper left to select "Mixer"
  4. Create three vertical faders by using the New menu, then select Fader, then Fader 1. Repeat twice so that you thee faders
  5. Rename the first fader "pitch" by holding down command and clicking on the label below the first fader. Rename the second one MSB and the third one LSB. This step isn't critical, but it will make the tutorial easier to follow. You may also want the Pitch fader to be much taller than the other two.
  6. Connect the output of the Pitch fader to the MSB fader
  7. Connect the output of the Pitch fader to the LSB fader
  8. Connect the output of the MSB fader to the track that has the PShifter II plugin
  9. Connect the output of the LSB fader to the track that has the PShifter II plugin
  10. Your Environment should look roughly like this:

    Fader Arrangement

  11. Now click on the title of the Pitch fader, and make the following settings. The Input and Output settings must match. The range could go to the full 14-bit range, but Pitch Shifter II only allows 12 semitones, and 12 * 127 = 1542.

    1. Output: Control
    2. Channel: 1
    3. -1-: 20
    4. Input: Control
    5. Channel: 1
    6. -1-: 20
    7. Range: 0 1542

    Pitch Settings

  12. Now make the following settings for MSB:

    1. Output: Fader
    2. Channel: 2
    3. -1-: 1
    4. Input: Control
    5. Channel: 1
    6. -1-: 20
    7. Range: 0 12

    MSB Settings

  13. Now make the following settings for LSB:

    1. Output: Fader
    2. Channel: 2
    3. -1-: 2
    4. Input: Control
    5. Channel: 1
    6. -1-: 52 (this is the LSB CC that corresponds to MSB CC 20)
    7. Range: 0 127

    LSB Settings

You should now be able to smoothly adjust Pitch Shifter II using the large Pitch fader.

Why This Works

The Pitch fader generates a 14-bit MIDI CC message, which is great for smooth pitch bends. If Pitch Shifter II was a piece of MIDI hardware, then we would be done. Since it is a plugin, we need to turn the 14-bit CC into two separate Fader messages which point to the Semitones and Cents controls. We do that by sending the output of Pitch to both MSB and LSB. The MSB and LSB are both configured to take Control inputs (remember that Pitch is outputting Control), but they produce Fader outputs.

Pitch is outputting on CC 20, but since it is generating 14-bit CC messages, it will be outputting a second message on CC 52 (you can find this in a MIDI CC reference, or you can just look at the -1- menu an see that Logic helpfully identifies 52 as the LSB controller for 20. You could use any MSB-LSB pairing you want, I picked 20 arbitrarily, and that mandates that we use 52 as the LSB).

The next thing we need to do is adjust the Fader output settings so that they correspond to Pitch Shifter's needs. The Blue Cat link above indicates that the first insert will have channel 2, so I used that for both MSB and LSB. Then I experimented and found that when Output -1-: is set to 2 for LSB, LSB controls Cents. When Output -1-: is set to 1 for MSB, MSB controls Semitones.

The last thing I needed to do was scale down the maximum value of MSB and Pitch. Recall that we are working with 14-bit values. 2^14 = 16384, so we can use values from 0 to 16383. However, Semitones can only take on 13 values (I realize now that I was wrong - it can take on -12 to +12, including zero. That is 26 values. But you should be able to figure out how to clear up this problem on your own), so I set the maximum value of MSB and Pitch accordingly. (Note to editors: if you want to go back and fix this error in my answer, please also redo the screenshots for MSB and Pitch so that they match the updated text.)

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I know i'm a year late, but hopefull this will still help someone. I found a little VST today called Son of a Pitch. It's free and pretty darn good even if it is kind of hard to catch on as to how to work it at first, but it has 3 octaves up or down that you can adjust to your liking and it's automatable. After installing it though, don't look for son of a pitch in your VST list, you'll find it under Container - Synthedit.

http://www.vst4free.com/free_vst.php?id=871

Hope this helps someone out, cause VSTs like this seem hard to find :)

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