Holder Walkthrough: Spectral Editing, Freezing, and Processing

When we approach an audio effect, we usually try to understand it based on some conventional categories, such as delays, reverbs, modulations… Sometimes, however, some effects don’t quite fit into a specific category. Holder is one of these. Is it a sampler? A reverb? A video engine? All of them together?

Today we’ll uncover the secrets of Holder. In this blog post, we’ll talk about what’s under the hood and why Holder does what it does. In the embedded video walkthrough, we’ll put everything into practice and show how to get the best out of Holder. As always, if you want to jump straight to the video, scroll until the bottom of the page or check this link!

What is Holder?

In its simplest form, Holder is a device that samples some sounds, stores them in a buffer, and plays them back. However, it is not quite a sampler because something unusual happens between the sampling and the playback stage.

First of all, Holder samples eight continuous sound slices whenever it receives a trig. We can send this trig manually, or we can program Holder to generate trigs at a specific time interval (in sync or free-running).

These sound slices are like eight contiguous stop-motion pictures of the sound at a given time.

Then, Holder analyzes the spectral content of these “sound pictures” by dividing them into 2048 frequency bands and measuring each band’s amplitude.

The result is a table with eight columns of 2048 values each: they are eight spectral moments of our sound.

We can then chose what to do with these spectral photographs: we can play them in sequence, like a stop-motion; we can blur them one into another; we can eliminate some of the 2048 values to change the harmonic content, and so on. To better understand how this is possible, we need to introduce Holder’s video environment.

Video Environment?

We compared our eight sound slices to eight stop-motion pictures, and we did that on purpose.

Holder’s core is, in fact, a video engine: it takes our columns of 2048 values and treats them like video matrices.

It now can apply some of Jitter’s video tools, whose parameters we can control from the user interface.

In the image above, we can see a visual representation of what is going on inside Holder: the first animation shows the eight columns of 2048 colored lines; the second one the currently read slice; the third one the video processing.

First of all, we can choose which sound slice to play (i.e., which picture to show; i.e., which matrix to read). We have three options:

  • Read just the first matrix and play just the first sound slice (Still). The result is a freeze effect.
  • Read the eight matrices one after another and play all the eight slices in a row (Linear). It creates a rhythmically-evolving texture.
  • Read the eight matrices randomly (Random). It is similar to the previous mode, with a more pronounced and unpredictable effect.

Both the Random and Linear modes move from one slice to the other through clock impulses. We can define the time resolution on the user interface.

Then, we can apply some video effects to our matrices. You can think of it as a photo editing process whose controls are in the Dronizer panel.

The Void control creates some “blank stripes” across the matrix that remove some frequencies from the spectrum, creating some “holes.” Since these holes are linearly spread across the whole spectrum, they won’t match any harmonic series. The result is a balanced sound treatment that ultimately can lead to metallic sounds. A visual equivalent of the Void effect is the static lines effect.

The Swarm control injects some noise into the data, adding some grit to the sound. To continue with our video analogy, we can think of it as film grain or static noise on a TV.

Finally, the Blur section morphs one of the eight slices into another. It integrates each number of the 2048 rows to the corresponding one in the next slice. It can make Holder loses its distinct rhythmic texture, and, at high settings, it can create a vast, resonant reverb. A visual equivalent is like shooting a video with a very slow frame rate, where each frame seems blurred into the following one.


Then Holder converts our tables back into sound (after all, in the digital world, everything is numbers). It plays (or better, holds) a sound slice according to the playback trigs. If the playback mode is set to Still, Holder will play just the first sound slice. As a result, the Blur control won’t produce any noticeable effect in this mode.

To hear what Holder is capable of, check out the video part of this walkthrough!

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