New releases last two weeks: All genres

Notes: Rack power bringing 1.25A (1250mA) on both the +12V and -12V rails. There is a 5V rail, but it pulls from the +12V rail, up to 750mA. So only use the +5V rail if you have to.

Comes with 12-position flying bus cable and wall power supply. The wall power supply is the same unit as After Later Audio use on their cases, so there's plenty of headroom and you don't have to worry about memorizing which amperage is for which.

This should be roughly enough for 1 rows of modules in a 104hp case. If you need power for 2 rows, check out The Force module.

Notes: In only 12hp, Axis condenses all the classical blocks for the audio amplitude management, redefining the classical envelope -> vca -> mixer path. The idea is to manipulate a sound over three axes: its length, its volume, and its place inside the stereo field.

Axis is a dual envelope generator that features an integrated VCA, a crossfader, and a voltage-controllable mixer section. The initial concept was to combine digital control over an analog VCA to closely emulate the classic Vactrol sound. After more than a year of refinement, Axis has evolved into more than just that. It offers exceptional versatility, providing a wide range of waveforms and the unique capability to simulate the natural percussive qualities of different materials. All this is in a complete analog path.

For the function generator section, we choose a faster method over the classic AD/ ADSR style: a selection of waveforms studied to give back a precise musical effect can be selected with the shape knob. The function length is independent from the actual wave shape and can be settled with the fader timeX from 30hz to 15 seconds. Also, setting the timeX fader at its maximum level will leave the VCA open.

A more typical collection of envelopes can be found in the first half of the dial. All kinds of sounds, from plucked notes to long volume swells passing through lead-friendly lines, can be obtained here.

More unusual, the last section of the knob is thought to simulate the acoustic vibration of a percussed object. Starting with a triangular envelope, from this point on, the more you turn the knob, the more rebounds will be added, simulating the natural ring of a material. Using this section at low rates can generate complex envelopes that could also be suitable for the vibrato-style AM effect. The envelope generator section includes a mode switch (cycle,trigger,hold), a trigger/gate input, an EOC trigger out, a function output, a CV for the envelope shape selection, and one CV for time.

As a cherry on the cake, a crossfader is placed at the end of the chain, blending both Axis halves. With a dedicated fader and CV control, raising it will invert the L/R output, creating nice stereo effects or moving the voices around the stereo field.

The VCA section is more straightforward: it has an audio input/output[1] and a VCA CV input[3].

You can plug the audio I/O to use Axis in its completeness and eliminate a lot of cables and mess!

Soundwise, here at Clank, we are all about vactrols LPGs, but since we knew it's not the most versatile option on the market, we came up with a different design. Blending together a VCA with a not-so-step filter, we obtained a VCA with a nice mild LPG flavor: enough to sound not so "clicky" but not too slow to inficiate really fast sounds.

By default, the envelope created by the function generator is normalized to the CV in of the VCA. Plugging a cable into the VCA in breaks the normalization, in this way you can use a different source to control the VCA and free the function generator for LFOs or modulation duties.

The range Y fader sets the strength of the envelope, but you can also see this control as a volume fader, which is nice since you won't necessarily need an additional volume for your voice after the Axis. Take into consideration that since the Axis VCA is actually a low-pass gate, lowering the rangeY fader also affects the cutoff frequency. The range fader also has its CV control to program dynamic changes to the sound. Basically, it's a VCA over a VCA that permits every note to be at different intensities. Last but not least, Range CV can also be fed by a unipolar modulation CV to obtain vibrato effects or audio rate AM modulations

Notes: Chaos is excellent for modulation purposes or as a clock multiplier/ divider, but that's only scratching the surface... It takes a different approach to writing sequences than traditional sequencers, as it is built on six touring machines combined with an effective pattern and clock generator. One of the biggest challenges in electronic music production, especially when it comes to sequencing, is finding that sweet spot between hands-on control and possibilities.

It can be frustrating because many sequencers with lots of fun and playable controls don't always pack the punch you need. On the flip side, you have those bigger menu-based sequencers with tons of options but can feel overwhelming with all the programming they require. It's designed to help you overcome these challenges and make your music-making experience smoother and more enjoyable, whether you're jamming or writing a song you want to execute live.

Typically, a sequencer starts with a blank canvas. However, with Chaos, you begin with all possibilities at your disposal and can easily narrow them down to fit your vision with just a few adjustments. This makes creating a sequence that conveys a specific mood quick and straightforward. Once you have established this initial mood, you can loop it from the last step to step 32 whenever you hear something you like. At this point, you can choose to modify the entire loop or adjust the parameters of any individual step. There is no need for extensive menu navigation; simply pressing a button and turning the encoder gives you control over parameters such as gate time, gate probability, gate width, gate ratcheting, gate swing, notes, scale, slew, and slew amount.

The LED bar continuously displays the voltage output of the selected channel, as well as the gate and each parameter's value, eliminating the need for a screen. You can save and recall the entire sequence of its six channels at any time. Additionally, there is an internal function that allows you to randomize all parameters or just a select few within a specified range, helping you discover new melodies to work with.

Chaos is an endless reservoir of tunes and is incredibly quick and powerful for composing sequences, gate patterns, or modulation. In a short time, it will become the brain of your system.

Six CV outputs can be used for a wide range of applications; everything from chaotic modulations to fine-tuned sequences can be obtained. Thanks to its interface you can quickly adjust the voltages from where the random engine picks new values and then edit them in every aspect.In addition, Slew amount, Quantization, and external sampling are available on every channel.

Thanks to its 6 gate outputs, Chaos can be used as your system's quick and effective clock manager and gate pattern generator. Chaos also provides a stable master clock (10mS to 10Sec) from a separate output and can be clocked from external devices. On every channel, you can set Probability, Width, Swing, Ratcheting, and Time as a multiplier/divider of the master clock or unquantized in mS.

You can freeze the last 1 to 32 steps of randomly generated CVs and Gates in a locked loop when you hear something you like. Loops are not static; every parameter of Chaos can be used again to change the loop behavior in a non-destructive way.

Entering sequencer mode means taking control of every aspect of the looped sequence generated by the random engine. You can change time, width, probability, ratcheting, slew, slew amount, note, note deviation, etc., for each of the 32 steps of all six channels.

Thanks to the external input, you can substitute the random generator with external voltages, transpose a sequence on the fly, and a lot more.

If you're more into generative stuff or want to add a bit of craziness to the patch, you can use the Chaos function to randomize all the parameters on a channel. A sophisticated control named entropy is available on every parameter to set the distance of the new value from the last one.

Chaos can save and recall 10 slots where you can save entire sets or preferred channel behavior. Recall can also be done with an external voltage.

Notes: The name, indeed, comes from ancient Greek mythology since Proteo was a shapeshifter who could assume whatever shapes he preferred. In this way, our Proteo, has not a precise sound on its own but a clever mechanism that permits to acquire and transform every signal into waveforms. What if you can use your envelopes, LFOs or any other signal as a sound source?

What sets it apart from other oscillators? What's very different in Proteo is its internal pseudo-tape recorder, which is capable of continuously acquiring and transforming any external signal into waveforms and morphing them from a basic sine.

In Proteo, waveforms are not a static digital representation of a sound; they can continuously evolve in a very organic way, and tape loop time is a fundamental factor: changing it will drastically affect the resulting output even with the same sources at the inputs. Slowing down the time will capture a bigger portion of the incoming source with more harmonics. As a result, increasing it allows to capture up to low audio rate signals or really small fragments of the signal.

Exploring the interaction between Proteo, the sources and the time will force you to change your mind about how sounds and harmonics can be generated: visualizing how different shapes can sound and looking for new sources to generate YOUR waveform is the fundamental idea behind Proteo.

Proteo is also stereo, thanks to the Span knob you can easily detune one oscillator from the other to create nice stereo effects. Beside the common pitch the two oscillators have independent acquisition paths and morph controls, each one can emit different waveform.

Notes: Thererec is a 6hp smart dual-function generator based on a different approach! Two modern proximity sensors have replaced all the Attack/Decay thing, and this not only saved a lot of space but also turned Thererec into a whole new thing: a fusion between THEREmin gestural expressiveness and a tape RECorder,

Thererec, indeed, can quickly capture your hand movements and translate them into complex Envelopes and LFOs, adding a lot of expressiveness to your set. Once recorded, your movements can be mangled in both time and amplitude; they can be cycled or triggered in one-shot mode, letting you create complex but synchronized control voltage streams.

A straightforward movement with immediate feedback: move your fingers, listen, and connect yourself to the environment. Your body will do the rest.

Thererec sensors will track your movements to generate a voltage flow, and the LEDs and the CV outputs will reflect those movements.

Notes: Toolbox is the newest essential utility module for your modular system. It's designed to summarize and replace all those necessary small one-function modules, often overlooked due to their space and cost requirements. With a compact 12hp design, it offers a comprehensive selection of carefully curated blocks to expand and enhance the potential of every patch. The module is also specifically designed for internal interaction, allowing the combination of various basic blocks to achieve compelling outcomes, from complex rhythm creation to unusual sound shaper. Every system needs a Toolbox!

Since VCAs are always not enough, the first two blocks on the top row consist of two linear and very fast VCAs, which are also great for AM modulation. They are arranged from left to right: input (DC coupled), control voltage input (ranging from 0 to 8V), and output. The two inputs and control voltages are normalized from left to right, facilitating easy stereo operation. These VCAs, designed primarily for voltage attenuation, are versatile tools that excel in scenarios requiring linear response. With audio, their true strengths shine when applied to amplitude modulation (AM) scenarios, where the benefits of linear control become quite significant. Although they are optimized for AM and voltage control, using exponential envelopes with these VCAs can transform them into two highly effective and fast VCAs for audio applications.

The threshold CV (0-8V) is crucial for the functionality of the blocks labeled with an asterisk (*): AND/OR gates, sequential switches, and flip-flops. By default, the threshold for each block (the voltage that must be reached at every input for the circuit to operate) is set very low, allowing almost any positive signal to be used. By increasing the threshold with an external voltage, you will change the point at which the circuits marked with the * begin to operate. This may seem a little tricky at first, but once you master all the functionality of the Toolbox, the Threshold CV rarely found in other Eurorack modules will open up many more possibilities!

Still composed of two identical parts, the second and third rows contain two blocks of two-channel summing (A & B). This region offers many ways to combine two signals. From left to right, input A, B, SUM out inverted SUM out, and two Boolean operators: AND/OR While any input signal can be used here, the first two outputs are primarily intended for audio sources. In contrast, the Boolean outputs are more suitable for summing gates and logic signals. This setup also allows for the use of both logic and analog signals together; don't hesitate to experiment with Boolean operators using analog or audio signals.For example, connecting two different LFOs to the input of the summing section can create many gate rhythms from the two Boolean outputs by varying the threshold with external voltages.

Summing mixers/Mult Out: This section consists of two 3-input summing mixers connected in series: the output of the upper mixer is routed to the first input of the lower mixer, allowing you to combine a total of five signals with two outputs available. To break this connection, insert a patch cable into the first input of the lower mixer. This action separates the two sections, enabling you to sum two sets of three signals each. Additionally, the lower section includes a multed output by default.

A bidirectional sequential switch is located at the center of the module and labeled with three "I/O" tags. This often overlooked component allows for a wide range of functions, from the most practical to the most creative. When a voltage exceeding the threshold level is applied to the * input, the switch connects the upper left jack to the lower right one. If the voltage is below the threshold, the lower left jack is connected instead. Being bidirectional, each I/O can function as both an input and an output, enabling a 2:1 or 1:2 configuration. Try using the switch at audio rate; this can function as a versatile oscillator waveform shaper. Think of something other than this block as a simple channel switcher!

On the right side of the sequential switch, we have a more classic block: the flip-flop. This block outputs a square wave at half the frequency of any signal applied to the input, whether audio or gate. Two flip-flops are available, which can be used individually or normalized in series. This block is handy for creating sub-octaves of square format from any sound or as a clock divider.

Offset / Attenuverters: Located at the bottom are two offset and attenuverting channels.This section comprises two identical blocks that can easily attenuate, invert, and offset any input signal. Each block features an input jack, one output, and two small knobs. The first knob functions as an attenuverter, allowing you to invert and scale the signal at the same moment. The second knob, the offset, adds a static voltage of +/-0-8V to the resulting output. This functionality is crucial when seeking a more refined control over voltage or a signal. Without any signal at the input, you can use the offset knob as a manual control generator for any control voltage (CV) in your system. For example, try to change the threshold with it.

Notes: Mutes goes above and beyond basic muting by allowing you to split groups of signals to multiple destinations, making it great for FX dub performing and varied signal routing.

Vactrols on the circuit gives to the switching a pleasing decay for both audio and modulation as well a totally click free muting.

Three-position switch: MOMENTARY signal pass-through (it springs back to the center when released); OFF (or muted) in the center; and ON to the right.

Notes: Module A-145 is a low frequency oscillator, which produces cyclical control voltages in a very wide range of frequencies.

Five waveforms are available: sawtooth, inverted sawtooth, triangle, sine and square wave. The LFO can be used as a modulation source for any number of modules - for instance modulating the pulse width or frequency of a VCO, modulation of the cut-off frequency of a VCF, or amplitude modulation with a VCA.

A three-way switch lets you select three frequency ranges, spanning from one cycle every several minutes at the lowest, to moderate audio frequency at the highest (about 4-5 kHz).

The LFO signal can also be synchronised, via the reset input.

Identical to the A-145-1, but only 4 HP wide and with additional LEDs for the square wave and the sawtooth signal.

Power consumption: 30mA at +12V and 20mA at -12V
Depth: 45mm
4 HP

Notes: Euphoria is a full analogue 8-stage phaser, delivering rich, vintage phase shifting with deep modulation capabilities.

A versatile phaser perfect for lush movement and evolving soundscapes in Eurorack setups.

Specifications & connections

8-Stage Phase Shifter
OTA-Based
1 Input for eurorack level (10pp IN)
1 Input for instrument level (500mVpp)
Built-in LFO
Current Draw: 58mA (+12V), 52mA (-12V)

Included in the box:

Euphoria Eurorack module
1x Ribbon cable
4x 3mm Screws

Requirements:

Eurorack case and power supply
Monitor or Amp.

Notes: Polyphonic sequencing from Elektrofon, the Klang allows you to program and perform chords and multi-layered harmonies. Circular clock-style display gives visual feedback and real-time indication of chord progressions.

Supplier's Notes:
«Klang» is a 4 voice polyphonic controller. It stores, traverses and manipulates chord progressions.

Overview

«Klang» is a unique take on polyphonic control within Eurorack.

Displaying chords in a circular clock-like display, and giving the user immediate control over every aspect without "menu diving" makes for an easy to use and inspiring module.

The module can store up to 99 chords, where each chord is made up of 4 voices.

Each voice is represented by a colored indicator on the clock-face which in turn is controlled by an encoder.

The indicators points to notes on the chromatic scale drawn in 360- around the clock-face.

Interface

The big grey encoder in the middle of the module lets you browse the chords - the active chord and total chord count is shown just above the encoder on the display.

The + button lets you ad a new chord. The new chord is added after the currently active chord, and the new chord is then set as the active chord.

The - button removes the current chord.

Inputs

The module has 3 inputs - 1 trigger input and 2 bipolar CV inputs.

Trigger input

The trigger input triggers a chord change.

If the direction input is unconnected, a single trigger results in a single step in the forwards direction.

Direction input (+-5V)

The direction input normalizes to a single step in the forwards direction.

You can feed this input a bipolar CV (+-5V).

Direction maps the total chord count to 5V. This means that +5V results in a single trigger progressing +n steps, where n is the total chord count.

A negative voltage will do exactly the same but resulting in backwards stepping.

0V equals no movement.

Transpose input (+-5V)

This bipolar CV lets you transpose the current chord up or down within 1 octave.

It is therefore a 5V/oct input.

The reason for this is that it is intended to be used with an analoge voltage source like the Pressure Points from Make Noise, or any other analoge sequencer.

It is much easier to fine tune a 5V/oct signal with a regular potentiometer than a 1V/oct signal.

Outputs

Each voice has a separate color coded 1V/oct CV output.

Notes: ADSR (Attack-Decay-Sustain-Release) is a module designed to generate a voltage, which acts as the envelope with the adjustable stages. This envelope, generated in response to the incoming gate signal or manually pushed button, can then be used to shape the sound amplitude via VCA, modulate filter's cutoff frequency or any other parameters expecting CV control.
It features exponential Attack, Decay and Release stages, switch to select fast/slow operation mode, push button with led indicator to manually activate the envelope.

Notes: Noise Engineering is excited to announce a limited-edition BIA. Same great Basimilus Iteritas Alia (with all the perks of an Alia!), spiffy new outfit.

The panel features black ink overprinted on a black powder-coated aluminum panel. These panels will not be sold separately.

Universal drum synthesizer with roots in the analogue world on a swappable 10HP oscillator platform

Basimilus Iteritas Alia is a parameterized digital drum voice with its roots in the analog world. At its heart, the BIA is a simple six-oscillator additive and FM synthesizer with waveform, harmonic spread, and envelope controls. An adjustable noise oscillator and an extreme take on a wavefolder round out its synthesis abilities. Its straightforward controls make sound design fun and performable: create sub-shaking kicks, snares, hats, and unique drum hits with just a few tweaks.

BIA is a classic percussion module but you'll be blown away by how much more it can do. Use it for leads, basslines, or build a whole drum kit with some external CV. Plus, the envelope output means you can use the BIA for shaping and modulating other parts of your patch.

Basimilus Iteritas Alia is available on our 10HP Alia oscillator platform. Buy an Alia module and use the included USB cable to connect to the Firmware Swap app and check out any other Alia firmware, free of charge, any time. More info can be found on the World of Alia page here. Hotswappable overlays are also available so you can easily panel your module to match your firmware, no assembly required.

Basimilus Iteritas Alia is the successor to the Basimilus Iteritas Alter. It was developed to sound nearly identical, with added features and new firmware-swapping capabilities.

Size and Power
10HP Eurorack
+12v:100mA
-12v: 15mA
Basimilus - small foundation - from Latin basos "foundation" with suffix -lus "small"

Iteritas - repetitiousness - from Latin itero "repeat" with suffix -tas "state of being"

Alia - another, other from Latin alia "other", also marine animals, or salty from Greek "halia"

"more small salty foundation of repetitiousness"

Notes: Patterns is a 4 channe modular sequencer designed for deep flexibility and hands on performance.

Each channel supports up to 64 steps, with essential creative tools like randomisation, probability, gate length control, swing, clock divisions, and more, giving you everything you need to build evolving, dynamic rhythms.

Its 4×4 grid layout makes programming intuitive and performance friendly, letting you quickly visualize your sequences and punch in steps with ease.

But the real power of Patterns lies in its dedicated Pattern button, your instant gateway to 16 different pattern slots. Switch between them on the fly, program your custom pattern chains, or use CV to jump between patterns and create unexpected breaks, fills, and experimental grooves.

Whether you're building complex arrangements or just jamming, Patterns gives you the immediacy and depth to stay in the flow.

Notes: Control Forge's core functionality is drawn from the E-mu Morpheus's insanely powerful (but hard to program on a two-line display) Function Generators. But now expanded into a supremely flexible modulation source encompassing elaborate one-shot contours, evolving cyclical patterns and sequences of arbitrary length and complexity.

At its most basic, it's an 8-segment function generator with variable time and target voltage level for each segment. Each segment's level can be defined either absolutely or relative to the ending level of the previous stage and can optionally be quantized to the nearest 1/12 volt, additionally, each segment's level may have a user defined range of randomness of either linear or gaussian distribution.

'Tempo Mode' lets you specify each segment's length in musical note values relative to a tempo set in BPM. The time scale may be modulated under CV control or manually via the encoder during runtime.

There are 67 different transition shapes between segments (indicated graphically on the display during selection), from linear and exponential shapes to various flavours of random, chaotic, and many more that don't lend themselves to one-word descriptions, including the ability to pass CVs directly through to the output for individual segments. Also included are 'DC' shapes that allow the module to be used as a sequencer with all of the module's available programmability. When combined with the Preset Sequencer described below, sequences can be hundreds of steps long and modified in real time manually or by CVs.

Each segment may optionally have a conditional jump mode that results in a jump to another selected stage if a particular condition is met. e.g. a CV being above or below the selected conditional value, the presence or lack of a gate or logic high at their respective inputs, rising or falling edges at the inputs, etc. So, in addition to one-shot shapes, extremely elaborate cyclical patterns can be programmed that evolve based on the various conditional inputs.

Control Forge's AutoChain functionality allows the creation of two very specific kinds of multi-preset patterns: A multi-preset retriggerable pattern (like a long syncable LFO), and a multi-preset 'envelope-like' pattern with retriggerability, an optional sustain section, and a 'release' section that's jumped to on gate fall. Two independent triggers can be programmed to fire in response to a variety of events and can be used to affect either CONTROL FORGE itself or external modules.

500 presets can be saved and recalled. a preset sequencer allows stepping through up to 200 user-defined series of presets under trigger, clock or manual control. This allows contours and sequences of almost unlimited length and complexity. All presets and sequences can be transferred to any number of Satellite modules, which can then operate as stand-alone modulation sources, completely independent of the Control Forge.

Notes: A sequencer and a filter-bank got together...

...And a love child was born !

Introducing NIGHT RIDER, from RYK Modular

Four multi model filters with stereo capability, combined with a six-stage four-channel modulation sequencer.

Finally a filter bank that unifies the control of multiple parameters, enabling a spaghetti-free approach to formant animation fun.

NIGHT RIDER cleverly turns the dials to where you want them, when you want, via it's unique modulation sequencer

Create dreamy swooshing 70's phaser filter sweeps
Phenomenal for phoneme vocal formant rasps and wheezes
Plucking great for strumming Karplus Strong twangs, and pinging filter pings!
Or, turn your silk into shredded cabbage, with the built in bad-ass clipping-saturator

Technical specifications

Frequency range - from rumble to wispy
Resonance/Feedback range - from tame to insane
Individual Filter levels - silent to beyond 11, for serious saturation-clipped sonic destruction

Features:

Four filter blocks, with multiple models , including:
6db BPF [ pingable ]
12db BPF [ pingable ]
12db variable width BPF
Comb Filter for Karplus Strom [ pluckable & flanger vibes ]
All Pass filter [ crazy Phaser vibes ]

Dual Input and Stereo output, with Pan control for each filter in the stereo field. Input can
be Mono [ CH1 - 1,2,3,4 ] or Dual [ CH1-1,2 CH2 - 3,4 ]
Modulation Sequencer capable of being clocked, scanned, and interpolated
CV inputs for sequencer Interpolated scanning, 1V/Oct frequency offset, Slew amount,
Resonance amount, Clock or MIDI clock input for sequence animation, MIDI CC
Memory slots for storing and retrieving Filter and animation setups, and retrieving preset formant, and chord based Filter setups

Vital stats:

Width 16 HP
Depth 25mm

52mA +12V
9mA -12V
0mA 5V

Notes: Add 3 more V/Oct and Gate inputs to your Vector Wave with the Expander

The Vector Wave Expander module from RYK Modular allows you to use CV and Gate to control the Vector Wave as a 4 Voice multi-timbral synth module.

And it looks nice.

Features:

3HP

Notes: Upgraded version of WMD's excellent performance mixer module, the PM MKII features four stereo or dual mono channels, CV control of levels, panning and aux sends, plus soft mutes per channel.

Supplier's Notes:
Need More Inputs?

Add four channels at a time to your Performance Mixer MKII setup, or you can use the Channels MKII as a standalone four channel mixer.

The expansion is simple -- identical channels, just more of them. Four at a time, up to four Channels units, for 24 total stereo channels.

A simple 16 pin 2mm pitch expansion cable is provided and is the only connection necessary. Units can be daisy-chained easily resulting in a clean setup.

Additionally, the outputs on Channels MKII still work when connected to the PM MKII. So you get a submix of AUX1, AUX2, and MIX available for whatever you may want to do, drum submixing, FX routing, etc.

Not Just an Expansion -- Standalone Operation
As a standalone unit, you get three stereo outputs, MIX, AUX1, AUX2. The buttons are soft mutes. It's a robust four channel setup.

FYI -- You can not connect CHANNELS MKIIs together without a PM MKII. The summing, buttons, and control brain is in the master section of the PM MKII.

Recording Outputs:

Pre and Post fade headers are available on the rear for connection to the DB25 MKII. Each Chanels MKII will fill 1/2 of a DB25 with the Pre or Post connections.

Specifications:

24HP
36mm Depth behind Panel Including Cables
Board Height Between Rails 111.5mm
Channel Input Gain: -12dB to +20dB
Fader Gain: -100dB to +5dB (Applies to Aux1, Aux2 also)
Pan Curve: -100dB at Hard L/R, -3dB at Center
All Inputs and Outputs (Including Sends, Inserts, Headers, etc) are IN PHASE
HPF: -1.3dB at 20Hz