Review – Momentum from Impact Soundworks

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Impact Soundworks’ Momentum is a Kontakt/REX/WAV percussion loop library. Not all that into loops? Don’t be too sure … this one makes them fun.


by Dave Townsend, Nov. 2017


First, an admission: I am not a loop guy. I’ve spent more than half a century learning to plunk my fingers down onto a keyboard at the right time and in the right places, and loops have always seemed to me to be lazy a shortcut to music composition and performance.

But once in a while, I bend my own rules. Percussion is one area where I don’t have too many ethical qualms about using loops in lieu of a real performance, especially when it comes to tedious 3-minute shaker and tambourine parts. But I am still picky. Too often loops are either what-you-hear-is-what-you-get, or editing them to get what you want ends up being way too much work.

Well, Impact Soundworks has sucked me into the looping world with Momentum. Yes, they’re still canned performances. But these folks have made it so easy and fun to manipulate loops into something unique that I actually enjoy programming this instrument.

The loops are all human-played acoustical instruments, so they don’t sound mechanical or artificial. But if you’re looking for garden-variety hand percussion, know that these 100+ instruments lean toward the non-ordinary. Slapped cellos and guitars, spoons, a metal door, a plastic teapot and bicycle spokes are some of the more unusual “instruments”. Oh, there are some conventional pieces in there, too, such as bass drum, shakers, congas and cajon. But even they are often played in unconventional ways (such as striking a bouzouki with a rubber mallet), such that even ordinary instruments can come out sounding unexpectedly un-ordinary.


Disambiguation Note

Shakespeare asked “what’s in a name?” True, a rose by any other name would smell just as sweet. However, telling your wife you ordered a dozen graboids for your anniversary might lead to some confusion.

Unfortunately, both Impact Soundworks and Cakewalk released products named “Momentum” in the same month.

Cakewalk’s Momentum is a completely different animal, a tool for capturing musical ideas and storing them in the cloud. It runs on both mobile and computer-based operating systems, which means you can jot down a song idea on your iPhone while waiting for the bus, and then bring it into your DAW when you get home. A nifty idea, and we’ll be covering it in a future SoundBytes issue.



Momentum consists of two main .nki’s: Momentum.nki and Momentum Loop Mapper.nki.  The former will be your primary interface for editing and playing individual loops, while the latter lets you build a custom collection of loops and assign each one to a different key on the keyboard.

Pre-made loop constructions can be selected by dragging in Kontakt Snapshots. There are 72 snapshots included, not enough to come close to covering every possibility (there are over 2,500 customizable loops!). But they do provide at least a broad overview of the possibilities, so a good place to start is to load Momentum.nki and audition different snapshots to get an idea of the instrument’s potential.

Each of the percussion instruments is also included as pitched one-shot samples, each with their own .nki, for programming in your DAW’s piano roll view or playing by hand on a MIDI controller. The easiest way to approach this mode is via the Momentum Loop Mapper, which we’ll delve into later.

 Getting Started

Load momentum.nki and navigate to the snapshot folder in Kontakt’s Files view. There you’ll see snapshots categorized by BPM (80, 86, 110 and 140). Open the 110 BPM folder, as it contains the most snapshots. Drag one of the snapshots into the instrument header.


The main window is dominated by a view of the sliced loop. Here you can modify parameters for each slice independently.


What you’re looking at here is the prerecorded loop, sliced into individual hits. The number of slices depends on how many distinct hits there are in the loop. Each slice can be adjusted independently by pitch, volume, pan, filters or modulators. In this screenshot, we’re modifying pitch values.

Click on the die image to let Kontakt assign random values. It’s gray-colored and hard to see, and looks more like a snowflake than a die, but it’s there in the upper-left, under the label “RANDOM”. This button is a great inspiration-starter.

Next, enable the Kontakt keyboard display if it’s not already there.


Keys are divided into color-coded sections. The blue keys represent starting positions for playing back the loop; the more steps in the loop, the more blue keys there are. To play the entire loop, click on the root note, which is always C4 (or C3, depending on what your DAW considers middle C). To start the loop at some other point, click on one of the other blue keys (the slice number is shown in the information label below the keyboard).

Green keys are for transposition, from 1 to 7 semitones (click the yellow key to reset). Red keys enable various effects. Purple keys play one-shot samples.

And that’s about as difficult as it gets. Just drag in a snapshot and start playing!

Note the tabs at the bottom, labeled Main, FX and Mod Matrix. Click on FX to get to the eight built-in effects (EQ, compressor, transient designer, distortion, bitcrusher, delay, reverb and limiter). Aside from having randomize buttons, these effects are all pretty standard and self-explanatory, so I won’t bore you with the details. They only really get interesting when you modulate them via the modulation matrix, which we’ll discuss separately.


Customizing a Loop

Now that we’ve got a snapshot loaded, we can start playing around with it.

Here’s an initially boring shaker loop, which gets more interesting when it starts bouncing between left and right channels. Then, I randomize the pan settings using a MIDI CC in my sequence, so we get different random pan positions for every measure. Totally un-natural, I agree, but oddly pleasing. It sounds like the shaker player has had too much coffee and couldn’t stop dancing.

   Shaker Clip

In the next example I’ve chosen the “Tubular Adventure G” snapshot. Despite its name, the sequence was actually made from slapping an acoustic guitar body.

The raw loop is first played with no effects or modulations, then with volume, pan, filter and modulation applied to each slice. (The pan effect is especially dramatic if you listen with headphones.)

   Tubular Adventure Clip

You probably detected that there was a delay effect involved in that clip. But not a boring old straight-up delay. Instead, I had this one randomly modulate the feedback parameter of the delay effect so that the number of echoes is constantly changing.

Which brings us to the modulation matrix.


The Mod Matrix

Modulation options in Momentum are pretty deep for a Kontakt instrument. You normally only see this level of flexibility in synths. Click on the “Mod Matrix” tab at the bottom of the main screen to bring up the matrix.


The modulation matrix provides eight slots for routing modulations. You can choose from nineteen modulation sources and seven destinations. Any control within the destination effect can be modulated.

In the screenshot to the left, I have routed the LFO to the EQ’s high-pass filter gain, using a free-running sine wave as the LFO.

Back on the main loop screen, you can set the amount of modulation for each slice independently.

Let’s say you want some reverb, but only on the last hit of the loop. Or maybe you want randomly changing ADSR envelopes or a slowly-changing bandpass filter for a wah effect. All are achievable via the mod matrix.

TIP: don’t forget to visit the FX tab and enable the effect you’re modulating. They aren’t automatically enabled just because you added them to the matrix.

Note that, as in a synth, modulations are additive. That means you can set a base value in the effect itself and the modulation source(s) will be added to (or subtracted from) it. It also means you can modulate a single parameter from more than one source, e.g., LFO and key value. Every modulator has a depth control, but be careful because high mod depth values mean extreme modulation that might make some hits in a loop disappear.

Two of the more interesting modulation sources are “Random Uni” and “Random Bi”. This fun option generates random modulation depths for each MIDI note received (uni-directional or bi-directional, meaning positive-only or both plus and minus). So rather than enter one long-duration note in your PRV to kick off and sustain a loop, try instead entering a separate note for each measure. This will alter the modulated effect in a random manner with each measure, as if your percussion section was ignoring the producer’s instructions and having its own party.


The Loop Mapper

The other main instrument, Momentum Loop Mapper.nki, lets you map any loop to any key and thus build up a collection that you can select via MIDI notes.


Choose a loop from the menu at top, then click on a key to assign that sample to that key.

The keyboard display will reflect your assignments as blue keys.


There are a lot of instrument types to choose from, so it’s helpful to narrow the selection by choosing one of the nine timbre categories (e.g. glass, pluck, brush) and/or pitch ranges (low, mid, high or full).

Note the little speaker icon above the list. Click on this to toggle loop auditioning, handy for perusing loops.

Here you can also specify a time signature for each individual loop, as well as enabling pitch transposition (via the green keys). After you’ve made your choice, click the checkmark button to add the loop to the collection.

And yes, there is a Randomize button here, too. (Note: if the checkmark button isn’t enabled after clicking the randomize icon, click on a different loop name and then click back on the random selection. This might be a minor bug.)



As someone who doesn’t often use loops, I am very appreciative of easy-to-use UIs. This one is so easy that even I, a non-looper, was able to figure it all out in a few minutes without referencing the documentation. However, you should at least take a look at the PDF, because it’s concise and clear, and might even tip you off to some non-obvious feature (case in point: I did not figure out the keyboard shortcuts on my own, e.g. Ctl+Alt / Cmd+Opt to reset the entire grid).

Although this review has dealt exclusively with Kontakt, the library actually comes in three flavors: Kontakt, REX and WAV. Running it in Kontakt will give you the most options, but it does require the full version of Kontakt.

If you don’t have Kontakt, don’t despair; the WAV loops can be dropped into an audio track in any DAW. Even better, if your DAW supports REX imports (as many do), or if you have a REX player such as Propellerhead’s ReCycle, Cakewalk’s RXP or Spectrasonics’ Stylus RMX, you can import the REX versions and they’ll be automatically synced to your project tempo, plus you’ll be able to edit them using the player’s features.

Momentum is only available as a download – 12 GB if you get all formats, 5 GB for just the Kontakt files. Get it from the Impact Soundworks website. Price is $149 USD.





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