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Transposing quantized pattern via Slope?

Today I explored the Slope funcionality of the ER-102. I tried to transpose a running pattern by pressing keys on an attached keyboard (QuNexus) while staying within the choosen scale – and failed. Here’s what I did…

  1. I picked the MINOR scale and created a simple 3 Step Pattern: C, D#, G.
  2. I connected the note CV out of the keyboard to the Xmod input of the ER-102 and set the SLOPE for CV A to “1.0”.

When the ER-102 CONFIG.INI option “CV Slope Modifier behavior” was set to “post-lookup” everything worked as expected: like combining the ER-101 sequence and the keyboard notes with a Precision Adder. I could transpose the sequence for instance by an octave or single note steps. But his way I wouldn’t make sure that every final note would stay in the C minor scale.

So I set the ER-102 CONFIG.INI option “CV Slope Modifier behavior” to “pre-lookup”. Now every output note stayed within the C minor scale, but transposing by pressing keys on the keyboard didn’t work as expected at all. For instance switching octaves (pressing a C key one octave higher = switching from 0 to 1V) resulted in D, F, G#.

So what am I doing wrong here – and how could I make it work withou adding an external Quantizer? Any help would be very appreciated. Thanks!

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Okay, either nobody is interested in this topic or nobody knows the answer or my question is completely dumb. @odevices, Brian, could you please just briefly let me know what I’m doing wrong here?

index -> [table lookup] -> voltage

Pre-lookup means that the modifier is added to the index (i.e. scale degree). That is why 1V (which is just 1 when the slope=1) just shifts everything up by one index.

Post-lookup means that the modifier is added to the final voltage in the same way that an external precision adder would as you noted.

Chromatic transposition can be accomplished in one of two ways:

  1. Quantized output: Pre-lookup (slope = 12) but then you would have to use the 12ET voltage table.
  2. Unquantized output: Post-lookup (slope = 1)

Scalar transposition can be done only this way:

  • Pre-lookup (slope = Number of notes in the scale)

Thanks Brian! Scalar transposition is what I want to achieve. I used Pre-lookup already, but couldn’t find the right Slope setting.

If anybody else want’s to give it a try:

Example 1 – MINOR scale: It has 7 notes (C, D, D#, F, G, G#, A#) but I think what Brian means is the number of CV-A steps for one octave of the voltage table: It’s 12 steps (for instance 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47), so Slope 12 works.

Example 2 – BLUES scale: It has 9 notes (not important here), but also 9 steps per octave (for instance 27, 28, 29, 30, 31, 32, 33, 34, 35), so Slope 9 works.

Side note: It’s important to always use the first possible step of the voltage table for the spedific note. For instance in the MINOR voltage table CV-A 36 and 37 are assigned to 3.C.00, but the transposition works only correct if you use 36 and not 37.

Please correct me if I got anything wrong, but at least for these two scales it seems to work this way.

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That is exactly what I meant! Thank you for catching that.

Not sure what I’m doing wrong here ? When choosing post-lookup notes changes when cv from my keyboard is being input as expected. But when I choose pre-look up cv-a display values changes, but I can’t hear my sequence being transposed.

Even after following the suggestions in the replies after that post?

Not sure i understand the suggestion fully. For example “but couldn’t find the right Slope setting”, “so Slope 12 works”. How do you choose the slope setting - i though there was only slope X, Y, Z ?

There are 12 slopes in total:

3 (X,Y,Z) * 4 (CV-A, CV-B, DURATION, GATE) = 12 (slopes).

Page 15 of the manual describes these and has an example table in the upper right corner.

You need to set the slope (also could be called gain, multiplier, or factor) for the CV-A parameter for the mod channel in question.

Right - now i understand. Thanks for explaining. Here is what i did:

  • Chose Pre-lookup in the CONFIG.INI file
  • Track 1 contains my sequence going to VCO (CV A/Gate)
  • A keyboard CV goes to Er-102 group CV X
  • Group Modifiers: Slope/X is chosen

When i play my keyboard CV A values changes at Group Modifiers pages - but pitchsequence going out from track 1 remains unaltered.

Could you be more specific here?

Also, did you remember to add all the steps from Track 1 to the group that you are editing? Remember this section of the ER-102 is called GROUP MODIFIERS.

I meant that Slope and X is chose on the group modifiers select switches.

Yes i added all steps.

This has no effect. You are just choosing which slopes to edit with those switches. Did you actually set the CV-A slope to a number (like 12)?

FYI: If you have the high/slope/low switch set to slope and you press the GROUP MODIFIERS focus button, the ER-101 displays will show the slope values for each step parameter for the selected MOD channel.

Yes i set it to 12.IMG_0092

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No. That is 0.12.

Ah :grinning: now it works. Thanks !