Nemisindo, our new spin-out, launches online sound design service

We haven’t done a lot of blogging recently, but for a good reason; there’s an inverse relationship between how often we post blog entries and how busy we are trying to do something interesting. Now we’ve done it, we can talk about it, and today, we can launch it!

Procedural audio is a big area of research for us, which we have discussed in previous blog entries about aeroacoustics, whistles, swinging swords , propellers and thunder. This is sound synthesis, but with some additional requirements. Its usually intended for use in interactive content (games), so it needs to generate sound in real-time, and adapt to changing inputs. 

There are some existing efforts to offer procedural audio. However, they usually focus on a few specific sounds, which means sound designers still need sound effect libraries for most sound effects. And some efforts still involve manipulating sound samples. Which means they aren’t truly procedural. But if you can create any sound effect, then you can do away with the sample libraries (almost) entirely, and procedurally generate entire auditory worlds.

And we’ve created a company that aims to do just that. Nemisindo, named after the Zulu for “sounds/noise” offer sound design services based on their innovative procedural audio technology. They are launching a new online service,, that allows users to create sound effects for games, film and VR without the need for vast libraries of sounds.

The following video gives a taste of the technology and the range of services they offer.

Nemisindo’s new platform provides a browser-based service with tools to create sounds from over 70 classes (engines, footsteps, explosions…) and over 700 preselected settings (diesel generator engine, motorbike, Jetsons jet…). It can be used to create almost any sound effect from scratch, and in real-time, based on intuitive controls guided by the user.

If someone wants a ‘whoosh’ sound for their game, or footsteps, gunshots, a raging fire or a gentle summer shower, they just tell the system what they’re looking for and adjust the sound while it’s being created. And unlike other technologies that simply use pre-recorded sounds, Nemisindo’s platform generates sounds that have never been recorded, a dragon roaring, for instance, light sabres swinging and space cannons firing. These sound effects can also be shaped and crafted at the point of creation by the user, breaking through limitations of sampled sounds.

Nemisindo has already caught the attention of Epic Games, with the spinout receiving an Epic MegaGrant to develop procedural audio for the Unreal game engine. 

The new service from Nemisindo launches today (18 August 2021) and can be accessed at For the first month, Nemisindo is offering a free trial period allowing registered users to download sounds for free. After the trial period ends, the system is still free to use, but sounds can be downloaded at a low individual cost or with a paid monthly subscription.

We encourage you to register and check it out.

The Nemisindo team can be reached at .

Applied Science Journal Article

We are delighted to announce the publication of our article titled, Sound Synthesis of Objects Swinging through Air Using Physical Models in the Applied Science Special Issue on Sound and Music Computing.


The Journal is a revised and extended version of our paper which won a best paper award at the 14th Sound and Music Computing Conference which was held in Espoo, Finland in July 2017. The initial paper presented a physically derived synthesis model used to replicate the sound of sword swings using equations obtained from fluid dynamics, which we discussed in a previous blog entry. In the article we extend listening tests to include sound effects of metal swords, wooden swords, golf clubs, baseball bats and broom handles as well as adding in a cavity tone synthesis model to replicate grooves in the sword profiles. Further test were carried out to see if participants could identify which object our model was replicating by swinging a Wii Controller.
The properties exposed by the sound effects model could be automatically adjusted by a physics engine giving a wide corpus of sounds from one simple model, all based on fundamental fluid dynamics principles. An example of the sword sound linked to the Unity game engine is shown in this video.


A real-time physically-derived sound synthesis model is presented that replicates the sounds generated as an object swings through the air. Equations obtained from fluid dynamics are used to determine the sounds generated while exposing practical parameters for a user or game engine to vary. Listening tests reveal that for the majority of objects modelled, participants rated the sounds from our model as plausible as actual recordings. The sword sound effect performed worse than others, and it is speculated that one cause may be linked to the difference between expectations of a sound and the actual sound for a given object.
The Applied Science journal is open access and a copy of our article can be downloaded here.

The Swoosh of the Sword

When we watch Game of Thrones or play the latest Assassin’s Creed the sound effect added to a sword being swung adds realism, drama and overall excitement to our viewing experience.

There are a number of methods for producing sword sound effects, from filtering white noise with a bandpass filter to solving the fundamental equations for fluid dynamics using finite volume methods. One method investigated by the Audio Engineering research team at QMUL was to find semi-empirical equations used in the Aeroacoustic community as an alternative to solving the full Navier Stokes equations. Running in real-time these provide computationally efficient methods of achieving accurate results – we can model any sword, swung at any speed and even adjust the model to replicate the sound of a baseball bat or golf club!

The starting point for these sound effect models is that of the Aeolian tone, (see previous blog entry – The Aeolian tone is the sound generated as air flows around an object, in the case of our model, a cylinder. In the previous blog we describe the creation of a sound synthesis model for the Aeolian tone, including a link to a demo version of the model.

For a sword we take a number of the Aeolian tone models and place them on a virtual sword at different place settings. This is shown below:


Each Aeolian tone model is called a compact source. It can be seen that more are placed at the tip of the sword rather than the hilt. This is because the acoustic intensity is far higher for faster moving sources. There are 6 sources placed at the tip, positioned at a distance of 7 x the sword diameter. This distance is based on when the aerodynamic effects become de-correlated, although a simplification. One source is placed at the hilt and the final source equidistant between the last tip source and the hilt.

The complete model is presented in a GUI as shown below:


Referring to the both previous figures, it can be seen that the user is able to move the observer position within a 3D space. The thickness of the blade can be set at the tip and the hilt as well as the length of the blade. It is then linearly interpolated over the blade length so that each source diameter can be calculated.

The azimuth and elevation of the sword pre and post swing can be set. The strike position is fixed to an azimuth of 180 degrees and this is the point where the sword reaches its maximum speed. The user sets the top speed of the tip from the GUI. The Prime button makes sure all the variables are pushed through into the correct places in equations and the Go button triggers the swing.

It can be seen that there are 4 presets. Model 1 is a thin fencing type sword and Model 2 is a thicker sword. To test versatility of the model we decided to try and model a golf club. The preset PGA will set the model to implement this. The golf club model involves making the diameter of the source at the tip much larger, to represent the striking face of a golf club. It was found that those unfamiliar with golf did not identify the sound immediately so a simple golf ball strike sound is synthesised as the club reaches top speed.

To test versatility further, we created a model to replicate the sound of a baseball bat; preset MLB. This is exactly the same model as the sword with the dimensions just adjusted to the length of a bat plus the tip and hilt thickness. A video with all the preset sounds is given below. This includes two sounds created by a model with reduced physics, LoQ1 & LoQ2. These were created to investigate if there is any difference in perception.

The demo model was connected to the animation of a knight character in the Unity game engine. The speed of the sword is directly mapped from the animation to the sound effect model and the model observer position set to the camera position. A video of the result is given below: