I thought it a rocket (I'm not a Reaper user so I could be wrong though).

 

Yes, it's a rocket! You really looked closely, didn't you?

 

I thought it told me how much ink was left in my printer... I'm still looking for a VUMeter that has this feature!

 

Working on something new. Anyone guess what it is?

 

Sure, first you split the load into five parts for low, medium, really hot and super hot, then add water, then heat. You're building a washing machine for five different temperatures.
But why is this in Reaper forum?

 

... ...

 

Well, I am not familiar with these charts, but according to the symbols in there, I'd suggest this could be either a multiband distortion/waveshaper, or a multiband compressor, with parallel mixing.

 

You're right, @No Avenger. It's a flow chart for a washing machine. It will be a wonderful washing machine. Maybe in due course I'll give you a test unit of this washing machine so that you can test it against your washing machine. I can't wait to see which washing machine wins the race. Hop, little washing machine, hop!

 

Working on VU Meter 2:

 

RELEASE: VU Meter 2 (Alpha-Version 0.23)
The time has come! The first alpha release is here!

Here's what you can expect:

• A strictly limited set of features
• Lots of generic UI sliders
• Some minor bugs in edge cases

What you shouldn't expect just yet:

• Optimized CPU performance
• A tuned physics model
• A fully interactive GUI
• Embedded UI
• Other features not yet implemented

I'd love to hear your thoughts and bug reports!

---

Documentation:

Global Control

• View Mode: Selects between the horizontal bar display and the classic analog VU meter view.
• Options Group: Navigates through the different settings groups of the plugin.

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Options Group: Meter Engine

• Channel Mode: Determines how the input channels are processed, e.g., as Stereo, Mid/Side, or Mono. Stereo (summed) processes the summed power.
• Metering Mode: Determines the measurement method of the meter between VU, Peak, or RMS.
  
  Metering Mode: VU

• VU Reference Level (dBFs): Sets the level in dBFS at which the VU meter shows 0 VU (only in VU mode).
• K-Filter (VU/RMS): Activates a frequency weighting (K-Weighting) to approximate the measurement to human loudness perception.
• Physics Engine: Selects the physics engine that simulates the behavior of the analog needle.
• VU Attack Time (ms): Sets the attack time* of the VU ballistics in milliseconds.
• VU Release Time (ms): Sets the release time* of the VU ballistics in milliseconds.
• Mass (%): Controls the simulated inertia of the analog needle.
• Stiffness (%): Determines the simulated spring stiffness that pulls the needle back to the zero position.
• Damping (%): Regulates the damping of the needle movement to control overshooting.

* Attack and release times specify the theoretical optimum. The needle's physical response, however, governs its actual motion, leading it to strive towards this optimum.

Metering Mode: Peak

• Peak Reference Level (dBFS): Sets the reference level for the peak measurement (only in Peak mode).
• Peak Decay (dB/s): Determines how quickly the displayed peak value falls off in dB per second.

Metering Mode: RMS

• RMS Reference Level (dBFS): Sets the reference level for the RMS measurement (only in RMS mode).
• K-Filter (VU/RMS): Activates a frequency weighting (K-Weighting) to approximate the measurement to human loudness perception.
• RMS +3dB: Activates a +3dB boost for the RMS signal to align it with the AES-17 standard.
• RMS Window (ms): Defines the time window in milliseconds over which the RMS value is calculated.
• RMS Decay (dB/s): Determines how quickly the displayed RMS value falls off in dB per second.

All Metering Modes:

• Peak Hold: Activates the function that displays the highest level for a certain time.
• Peak Hold Time (ms): Defines how long the peak hold value is held before it decays.
• The Peak Hold decay time is hard-coded and is always double the main needle's set decay/release time.

​

---

Options Group: Scale

• Scale Type: Selects the type of scale between the classic VU scale, an amplitude scale (6dB steps), and a loudness scale (10dB steps).
• Scale Logarithm: Adjusts the curvature of the logarithmic scale to stretch or compress the display.
• Scale Min (dB): Sets the lowest visible dB value on the scale.
• Scale Max (dB): Sets the highest visible dB value on the scale.
• Scale Horizontal Stretch (%): Stretches or compresses the analog scale horizontally (VU meter view only).
• Scale Vertical Position (%): Shifts the analog scale vertically (VU meter view only).
• Tick Thickness: Determines the thickness of the scale markings (VU meter view only).
• Black Arc Thickness: Sets the thickness of the black, normal range of the scale arc (VU meter view only).
• Red Arc Thickness: Sets the thickness of the red, over-driven range of the scale arc (VU meter view only).
• Arc Feathering (%): Controls the feathering (anti-aliasing) of the scale arcs for a smoother appearance (VU meter view only).
• Oversampling Threshold (px): Sets the minimum width in pixels at which the VU meter's scale is rendered. If the meter's size falls below this value, the scale will still be rendered at the higher resolution and then downscaled (VU meter view only).
• Bar Tick Width (px): Determines the width of the scale markings in the horizontal bar view.

---

Options Group: Coarse Ticks

• Show Coarse Ticks: Toggles the display of the coarse (1dB) scale markings on or off.
• Coarse Ticks Min (dB): Sets the starting point for the display of the coarse ticks.
• Coarse Ticks Max (dB): Sets the ending point for the display of the coarse ticks.
• Coarse Ticks Target (dB): Defines the dB value at which the coarse ticks reach their maximum length.
• Coarse Ticks Min Length (%): Sets the minimum length of the coarse ticks (at the edge of their range).
• Coarse Ticks Max Length (%): Sets the maximum length of the coarse ticks (at the target point).
• Coarse Ticks Curve (%): Determines the curve used to interpolate the length of the ticks between their minimum and maximum.

---

Options Group: Fine Ticks

• Show Fine Ticks: Toggles the display of the fine (0.1dB) scale markings around 0dB on or off.
• Fine Ticks Range (dB): Defines the range around 0dB in which the fine ticks are displayed.
• Fine Ticks Min Length (%): Sets the minimum length of the fine ticks.
• Fine Ticks Max Length (%): Sets the maximum length of the fine ticks.
• Fine Ticks Curve (%): Determines the curve for the length progression of the fine ticks.

---

Options Group: Needle

• Needle Select: Selects whether to edit the settings for the main needle or the peak hold needle.

Main Needle

• Needle Thickness: Determines the base thickness of the main needle.
• Needle Feathering (%): Controls the feathering (anti-aliasing) of the needle edges for a smoother appearance.
• Needle Shape: Selects between a Tapered and a Trapezoid needle shape.
  • Trapezoid Needle Length (%): Adjusts the length of the trapezoid needle.
  • Needle Taper Length (%): Controls how much the trapezoid needle tapers towards its tip.
  • Needle Taper Curve (%): Influences the curve of the taper on the trapezoid needle.
  • Taper Center Width (%): Defines the width of the non-tapered area in the middle of the trapezoid needle.

Hold Needle

• Hold Needle has the same set of parameters as the main needle but affect the red peak hold needle.

​

• Motion Blur: Activates a motion blur effect for the needle to soften fast movements.

• Max. Smear Opacity (%): Sets the maximum opacity of the motion blur.
• Smear Falloff Curve (%): Controls how quickly the motion blur trail fades out.
• Smear Quality: Determines the smoothness of the motion blur effect.

​

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DOWNLOAD:

 

Last edited: Jun 24, 2025

Clever guy you are
I do not use Reaper yet I appreciate the work you put into doing something so essential.

 

I do, but I have no idea if I would need this and even then how to use this. Way above my paygrade. Also I am at v6 something and the flock has already moved on to v7.4. So, yes, old fart but I am happy with all these smart genius solutions people come up with!

 

cool! can we have both (old and new versions) installed at the same time or there is a risk of conflict or something?

 

Yes, of course. There will be no conflicts of any kind.

 

It'll get a lot easier to use (and grasp) once it's past the alpha stage and all the core features are implemented (there's still A LOT to come). I really focus on making sure the features end up being useful, plentiful, and intuitive to use.

 

....and understandable for really old fartz......At least the pictures are big enough for me to read with my glasses....

 

Certainly impressed by the presentation in the post, downloading now! Potential best itb VU meter?

 

That depends on what you mean by "best ITB" and which VU Meter you're referring to.

VU Meter v1:

• Simple, yet convincing physics simulation
• Excellent CPU performance (see here: post-708927)
• Many customization options
• Some GUI quirks

VU Meter v2 (Alpha):

• Great physics simulation (the best I know of*)
• Still acceptable CPU performance (but on the hungry side)
• Many customization options (and alot more to come)
• No GUI implemented yet
• Currently in early alpha status

*but I might be biased here, though – others will have to be the judge of that.

 

Last edited: Jun 24, 2025

Alright, I'll give it a try. So here's a quick lesson:

An analog VU Meter is actually built quite simple and works like this:

• Rectifier: The audio signal (an AC voltage) at the input of the VU meter is fed into a full-wave rectifier, which converts the signal into a DC voltage. To put it simply, the positive and negative swings of the waveform are folded together. This step is necessary because we want to see the signal's absolute deflection, not the oscillation of the waveform itself.
• Coil: This rectified voltage is then passed to a fine coil, which is situated within a permanent magnetic field. When current flows through the coil, it generates its own magnetic field. This new magnetic field repels the permanent one, causing the coil to rotate. A needle is attached to this coil, and the coil's rotation causes the needle to move.
• Spring: To prevent the needle's own inertia from causing it to slam to the right side of the scale the moment the coil moves - that is, to make the needle show us something meaningful at all - a small spiral spring is attached to the system. This spring exerts a counter-force against the coil's rotation. It constantly pulls the needle back towards the zero point, or, if there's no input signal, the spring ensures the needle rests at its home position on the far left.
• Damping: Damping is achieved through air resistance or electromagnetic eddy currents, which prevent the needle from oscillating wildly.

The combination of these parts gives the meter its ballistics. A standard VU meter is calibrated to respond in about 300ms to correctly display a 1kHz sine wave test tone.

But here's the catch: not all VU Meters are the same! Modern VU Meters are often much faster than vintage ones. There's a wide variation in behavior across all models, old and new.


Okay, so let's get to the why:

VU Meters offer a ballistic response that's excellent for determining the momentary loudness of a signal. This is similar to, but not the same as, RMS or LUFS-M.

• The advantage of a VU Meter's ballistics over RMS is that it's being closer to how we hear loudness.
• The advantage over a modern LUFS-M meter is, again, its reactive behavior. The disadvantage is the lack of frequency weighting (like the k-weighted filter in LUFS), which makes LUFS more accurate for perceived program loudness.
  
  The main disadvantage, as mentioned, is the loose standardization. While an official VU standard exists, it's far less precise and rigorously defined than the specifications for RMS or LUFS.

Make sense so far? Still with me? Great!

So that's the challenge for a developer: how do you digitally replicate a device with such inconsistent behavior and loose standards?

The most common solution is to build a digital model based either on RMS (which is then not a VU Meter), or on an envelope and a resonance filter response to model ballistics (I assume Klanghelm uses this method), or the "textbook" physics we discussed earlier.

The "textbook" physics is the approach in VU Meter v1:

• Rectifier: It takes the absolute linear value of the audio sample using abs() to rectify it.
• Coil: A driving force is calculated to push the needle forward.
• Spring: The restoring force of the spring is subtracted from the driving force to get a net force.
• This net force, divided by inertia (mass), gives us the acceleration.
• Velocity is calculated from acceleration.
• Damping: Damping is applied to the resulting velocity, reducing it with each step.
• And finally, the total velocity is then added to the needle's position.

The problem with this (and many other VU meter plugins) is that the physics are hard-coded for a specific scale (a standard 23VU scale). If you change the scale, the physics break.

This is why VU Meter v2 does something completely different.

Forget all the complex physics for a moment. The easiest way to think about VU Meter v2 is to compare it to the power steering in a car.

You give an impulse, the detector registers this impulse, extrapolates its trajectory, normalizes both the actual and target values, and then applies error correction toward the target value until the actual value converges with the target, or you give a new impulse.

Or in extra simple, the system does two things:

1. Figure out the Target: It instantly calculates where the needle should go. You can adjust how this target is calculated with Attack and Release controls.
2. Move the Needle: A physics engine then moves the needle to that target. How it moves is up to you. You control the physics with parameters like Stiffness, Damping, and Mass.

This approach separates "where to go" from "how to get there," which gives you incredible flexibility.

In a bit more detail (but still highly simplified):

• Detector: Instead of a simple rectifier, it calculates an RMS value with a short integration time (I'm still experimenting here, but I think I will replace the RMS smoothing with a rectifier). It then calculates a target value in dB. This target is then smoothed by the Attack and Release parameters.
• Normalization: This is the secret sauce. The target value and the current needle position are mapped to an abstract, internal "physics world". This crucial step ensures the needle's physical behavior remains consistent, no matter what scale values you set.
• Physics-Engine: In this normalized world, forces are calculated. The spring force is determined by Stiffness, and Damping counteracts the needle's velocity. The net force is divided by Mass to get acceleration, which gives us the new velocity and position. It's similar to v1, but the physics formulas are more complex.
• De-Normalization: Finally, the resulting normalized position from the internal physics world is converted back into a dB value for the needle on the GUI (so I can later derive numerical readouts and graphs).

So, VU Meter v2 is essentially a closed-loop control system, which is a novel approach for this kind of plugin. This new engine gives you total control over the meter's feel.

My goal is to visualize all of this in the plugin later, so you can make these adjustments intuitively without needing to be a physicist. It will be easy for beginners to use, but powerful for nerds to dig very deep.
But for now, my focus is on getting this engine tuned.

 

Last edited: Jun 26, 2025

OMG, you actually gave it a try and took a lot of time to explain it to me! Thank you! If only I were able to understand it. But I bookmarked it in my QOwnNotes program so I can study on it. I admire your faith in me!

The principle of a VU meter is only known by me by just experience: keep the needle in the red without overdoing it and the S/N ratio would be best. Especially for Sound on Sound, which was my first way of recording, the amount of noise increased rapidly with each copy.
But the only thing I record analogue is vocals. The rest is mid tot audio so these levels are not critical for noise levels.

Thank you for your elaborate explanation. Very kind of you!