Gain Structure (sample level, amplitude volume, track level...)

There are so many ways to affect sound level on the Digitakt: Trig velocity, Sample level, Amp volume, and Track level. Which one should I plock? Do they have different ranges? effects?

I set out to find out… and did!

First, the sound architecture diagram in the manual is lacking some detail. Turns out, the gain stages are in the pipeline like this:

  1. Sample Level & Trig Velocity
  2. Overdrive
  3. Amplitude Volume
  4. Filter
  5. Track Level
  6. Pan
  7. Delay & Reverb Sends
  8. Mixer

The first gain section is a pair of gain controls: Sample Level and Trig Velocity. These feed the Overdrive. Then come the Amplitude Volume gain section. Since Overdrive is non-linear, it is matters where you modulate gain (sound, plock, and/or LFO): If you do it before Overdrive, you affect the timbre. If you do it after, just the volume.

The difference is often subtle. To hear it clearly, pick a sample like “Anasine”, and set it to loop. Also set Overdirve up all the way. Finally, set trigs 1, 4, & 7, and plock them as follows:

  • Trig Velocity 4, Sample Level 100 & Amplitude Volume at 100
  • Trig Velocity 100, Sample Level 20 & Amplitude Volume at 100
  • Trig Velocity 100, Sample Level 100 & Amplitude Volume at 20

The final sound level will be the same for all three (pretty quiet). The first two will be the same, less Overdrive. The third will have more Overdirve, but be the same volume.

The Track Level comes after the filter stage. Alas, you can’t plock Track Level, so you can’t choose to driving the filter always affects the volume. Note also that Track Level comes before the Delay & Reverb sends, not in the final mixing stage, as I might assumed based on the diagram in the manual.

Lastly, I took a lot of measurements to determine the gain curves of the four gain controls. Three are identical, Sample Level, Amplitude Volume, and Track Level, if you assume a setting of 100 is nominally 0db, then they follow this curve:

Trig Velocity has less effect:

[ These are 40 log₁₀(x/100) and 20 log₁₀(x/100) respectively. Or if you’re thinking in terms of sample processing, the first three each multiply the sample by x²/10000 where as the last multiplies by just x/100. ]

So, if you’re going to plock, you have less range with Trig Velocity than Sample Level… which might be good, or bad, depending on what you want. Also, remember that Sample Level and Amplitude Volume can be set in very fine increments, whereas Trig Velocity and Track Level are only integers.

Hope this satisfies your curiosity!

Edit: Renamed “Master Level” to “Track Level” to match the manual.
Edit: Updated with correct location of “Track Level”, and added a clear way to hear the effect of gain stages on Overdrive.

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Points for performing tests, bonus points for including graphs with analysis! :thup:

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Are the channel level (master) and level in the mixer not the same thing? Curious as this is how it is on the A4/AK perf mixer.

Trig velocity simply scales the volume of the track, that’s why it has an offset in your graph. The resolution will increase if you lower the volume.

Regarding filter non-linearities, this means that there are saturation stages in the filter so that it doesn’t sound stale.

The Sample/Amp volume stages are before the Filter, and the Track Level naturally controls the track ‘master’ so to speak.

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Yes, the “LEV” parameter that appears on the bottom left of the display on most screens, and controlled by the LEVEL/DATA knob, is the same parameter as appears on the Master screen, controlled by the A thru H knobs. These are both now referred to as Track Level in the above, to match the manual.

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True, I measured the effect Trig Velocity while keeping everything else constant. I’ll map out it’s effect over different ranges… “for science” (and 'cause I’m an OCD nerd!)

So, Track Level comes after the filter? Hmmmm… I couldn’d find a setting to make that clear (like the 20/100 experiment I did for Overdrive)… I’ll keep hunting!

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Track Level turned down will silence the track completely. :wink:

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Here is the signal flow chart from the manual:

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Yup. Spent lots of time with that before I started. It doesn’t really tell you where the track level is applied, nor what the effect of trig velocity is. Plus, I’m to much of an engineer not to want to know the relationship between 0…127 and db… Hence my investigations!

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intresting… the amp is before the filter

I measured it out. Trig Velocity has the same effect no matter what the other gain settings. That is: It is effectively an independent gain stage at the start, just with narrower db range mapped onto 1 to 127 than the other three.

I was finally able to pull out the clear difference between driving the filter and then attenuating with Track Level, vs. the opposite. Alas, since you can’t plock Track Level, you can’t make use of this feature much. (And it is a somewhat involved experiment using multiple tracks.)

I’ve updated the report above.

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Thank You mzero.
very valuable !

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I’m confused on what the level, volume, and sample level controls on the DT actually do. The manual says:

  • level = overall volume of the active track
  • volume = volume of the sound, independent of the overall track level.
  • sample level = level of the sample.

I’m not sure why I would adjust one over the other. I usually just keep the level and sample level at 100 and adjust the volume to suit. Maybe someone can clear this up for me. Thanks.

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Level = mixer channel
The other two are somewhat paired. The sample is the lowest of the level settings and the volume is sound which contains a sample. Different settings are made for gain staging which allowing you to get an overall uniform level.

If you are only using 1 sample per track and not doing any sample flipping, it doesn’t really matter what one you adjust. The end result will always be the same.

When you start getting into flipping to different samples/sounds on the same track, you need to be careful that the volume of each one is similar so the volume doesn’t jump over the place.

Sample flip - adjust at the sample level to match.
Sound flip - adjust at volume of each sound to match.

Mixer level would be best suited for mix/performance.

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https://www.elektronauts.com/uploads/default/original/3X/f/6/f63af36b2b2d3a4fbf77bc925f4834510b1f0041.png

I haven’t done tests, but it also seems that the level in the sample engine would also change the input gain of the overdrive. It’s not analog, but still should lend to different output.

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Also, I try to leave SRC LEV and AMP VOL at 100 (that also means dropping AMP VOL from 110 to 100) using the Track Level as output gain. I also try to leave the Master at around 75%.

If I need more gain, I usually just nudge the master a bit. This gives plenty of headroom and really gives the FX plenty of space to shine.

Just my approach to keep things from going “all knobs up.”

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Here’s some useful information:

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Thanks folks, it’s beginning to soak in.

I believe they are also there to offset bit reduction and overdrive. You have access to the distorting parameter and a volume parameter on the same page so you can distort a sound live whilst keeping control of the volume.

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So, just like overdrive and amplitude volume are on the same page, bit reduction and sample volume are on the same page to provide control of the volume when using those parameters.

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