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Last Friday afternoon, we went to Zurich University’s (UZH) historic atrium (“Lichthof”) to participate in a test, comparing different loudspeakers with and without Illusonic Clarity, for live speech and music reproduction.

The different loudspeaker systems under test were:

– A: Foohn FP-22 portable speaker

– B: Foohn LX-150 line-source speaker

– C: Foohn DLI-230 dsp-controlled line-source speaker (array almost twice as long as B)

From A, B, to C was clear improvement, in terms of intelligibility and reduction of reverberance.

For Clarity, we measured two microphone positions for each loudspeaker type. Based on the measurements, we specified bass, low, mid, and high acoustic parameters, including RT60. These parameters were loaded to Raspberry Pi (Raspi), on which Clarity ran with 3 ms latency. The Raspi was connected to the mixing console via analogue.

For C, Clarity clearly reduced reverberance of the Atrium, even on all-behind positions. Clarity’s effect adds to the line array’s beamforming improvement.

For A and B, Clarity also clearly reduced reverberance at positions not far beyond reverberation radius. Once the soundfield is fully diffuse, there is nothing to win. So A worked well and was improved by Clarity up to a certain distance (approx. 1/3 of length of Atrium). B extended that maximum distance, and C had reach up to end of Atrium.
 

Clarity is our DSP-based room optimization technology, developed for nearly a decade. It optimizes a room beyond what room eq can do. It takes away parts of the source signal, which later on the room will add again. Perceptually, with Clarity, a music or PA system sounds as if the room would have more acoustic full range absorbers.

Clarity development was driven as a feature for our audio processors (IAP). A couple of years ago, we did exploratory tests in the Opernhaus Zurich, where Clarity is applied on the Studio stage (via our low delay plug-in).

Mid January a test is planned in the historic assembly hall of Zurich University. Acoustics are not satisfactory there, and acoustic treatment possibilities are very limited. We have had another request from world-renown ETH Zurich assembly hall. Though, as they were not looking for experimentation, but a device, we had to decline.

We can’t pull off another hardware device (besides IAP) and an entirely new business. But in order to small volume provide to selected venues Clarity, how can we build in low volume with low cost a hardware device?

Take a Raspberry PI 3 (Raspi), add a high quality stereo ADC and DAC and chassis. Bill of materials of USD 200 per unit! The rest of the problem is software:

1
Latency !
Usually a problem with Linux based systems. ADC and DAC connect via I2S, which is already better than USB. Then, we use Arch Linux ARM, which runs Clarity with maximum real-time priority round robin scheduler. The Arch Linux has only 14 processes running in total, so almost complete CPU is dedicated to audio processing. In order to reduce heating, the CPU is configured to run at minimum frequency (600 MHz instead of 1.4 GHz). Processing buffersize at 48 kHz is 32 samples. A daemon logs audio hick-ups. Several days of running it reported no hick-up at all. Externally measured latency is 2.7 milliseconds! This is low enough for any live application.

2
Reliablity !
The system is configured such that when starting the Raspi it will automatically start running Clarity. A daemon is monitoring it. In case audio processing crashes, it will automatically be restarted within a few seconds. Also, the Raspi may be disconnected any time from power. To mitigate risk of some data damage of its memory card, the file system is configured such that never data will be written to it. Any written data goes just to RAM.

3
Configuration and Tuning
To tune the system, a macOS/Windows/Linux software has been developed, writing a config file to the Raspi, containing all parameters. Real-time changes are possible. Parameters are permanently stored in Raspi. So it just has to power on to do its job. Besides Clarity, we also added parametric equalizers.

Let’s see, if the mentioned historic assembly halls will get substantial improvement thanks to Clarity. If yes, we have now a possibility to deliver a device that can do this job. Once this goes through well, other doors will be opened. This is iteratively working the ladder up, step by step, to possible success.
 

IAP Update 8.4

Pro Audio and Automotive projects have been the driver for update of our Immersive technologies. Dozens of Dolby Atmos music productions have used our upmix plugin for its great sounding reverb (depth, immersion) and phantom-center extractor (center). Alone since our previous IAP release, half a year ago, we did update our plug-ins three times, based on user’s needs.

With Version 8.4 we are consolidating these improvements for our IAP users. Depth and Immersion are fully revised and now allow for more effect. Clarity is more effective with less timbral change.

Download the update here.
 

Changelog (8.3 => 8.4):

adapted apps for macOS 12 and Win 11

revised Clarity, less timbral change, improved performance without tuning

revised Depth, improved early reflections, preprocessor, and equalizer

replaced Immersion, new de-correlators

sound and timbre is now similar for all supported loudspeaker setups, previously front-only setups were quite different to surround setups

orientation left, right, rear improved (depth better adapted)

fixed bug, where default presets had mono upmix on instead of off
 

IAP Update 8.3

Since the last update, we have had good progress on our immersive technology (Depth, Immersion features), being used in our upmix, binaural, plug-ins, and automotive licensable products.

We back ported these improvements to IAP SHARC DSP. Depth and Immersion have never been so nice as now. This also allowed us to make these effects a few dB stronger, while maintaining clean sound.

List of main changes:

revised dsp depth

revised dsp immersion

fixed bug, where immersion pre-delay was too large (echo effects)

fixed bug, where mono upmix could not be switched on

IAP Calibration delay trim slider now updates time plot in real-time

IAP Configuration layout improvements

Download the update here.
 

IAP Update 8.2

Feedback from our pro-audio plug-ins and a master diploma thesis on Clarity injected innovation into our IAP product line.

IAP 8.2 improves many “Illusonic” algorithms, such as depth, immersion, and clarity.

New ad hoc center gain feature allows to change gain of center, even without a center loudspeaker.

Input delay range has been increased to 300ms, satisfying even the most complex time alignment needs in home cinemas. Believe it nor not, a high end system with high end projector needed more than the previous maximum 200ms.

Besides that, IAP software has been internally modernized and runs now natively also on Macs with Apple Silicon.

Download the update here.

Farewell Concert Fabio Luisi

Opernaus Zurich, Saturaday June 19, 2021, 19:00

The livestream and video on demand will be available free of charge on the web link above from Saturday 19 June at 7pm until the end of June.

3D Sound

Viewers will be able to choose between stereo and 3D sound. The 3D sound is made for headphones listening. By directly controlling the listener’s ear input signals, an illusion of “being at the opera” is generated. Sound is recorded with an Ambisonics and other microphones and real-time processed with Illusonic’s microphone-to-3D-sound conversion audio processing software.

More details on the concert and its 3D sound can be found on opernhaus.ch

APEI Webinar

Remote Sound Tuning in Automobiles (video available)

June 9, 2021 
9:00 AM Pacific (12:00 PM Eastern)

Remote Tuning

Illusonic is maybe the company with most remote tuning experience. Almost a decade ago, we introduced the first Illusnoic Audio Processor. Shortly thereafter we introduced IAP Calibration software, with which Hi-Fi and home cinema customers measured their systems. With the same software we could remote-tune the custoomers’ systems.

Initially, remote tuning was done based on simulated frequency responses after tuning. Later, we added auralization and were so able to listen into customers’ listening room via headphones.

IAP Calibration software, specifically taylored for automotive is called CalibrationTool Automotive. It can handle up to 64 loudspekaer channels and 64 microphone positions.

Remote Tuning of Automobiles

We had already frequenty applied remote tuning to automobiles. It was mostly related to Immersive demos, for which we also linearly tuned the cars. Thanks to remote pre-tuning, we could minimize the time we had to spend with the actual car.

With the 2020/2021 Covid crisis and travel restrictions, remote tuning of automobiles quicly became a popular topic and we have seen a lot of traction in this direction.

Remote Tuning of Automobiles

During the webinar we show in real-time usage of CalibrationTool Automotive. It is shown by means of examples on how to remote tune based on data and graphs. The headphones auralization feature with head-tracking is also shown in real-time operation. During tuning, parameters are changed and simulated car sound in headphones changes immediately.

The test at Opera Zurich for stage monitoring (previous blog-item) currently can not be finished as the orchestra can’t play on-site.

A second stage inside the opera, called “Studiobühne” (“studio stage”), used for practising or performances with smaller audience, is often used with amplified voice and reproduced sound.

This room is not a lot acoustically absorbed, say, a bit more reverberant than ideally desired.

Thus ideal for a first live test of Clarity in the opera.

Will Clarity benefit reproduced sound here?

Will Clarity benefit live amplified voice?

As it is quite complicated configuring a workstation with plug-ins for minimum delay, we developed in the meantime a low-delay standalone macOS application with less than 3m total delay. This app can be used with (high quality) sound cards (analog, ADAT, MADI) and even Dante.

Michael Utz measured the studio stage with Illusonic CalibrationTool software (aka IAP Calibration) and tuned it with EQ and Clarity. Once ready, he invited us for subjective testing on-site. The real-time test was carried out with the low-delay macOS Clarity application, connected to the mixing console via Dante.

Clearly reverb in room is reduced, sound is more clear and more focused from the loudspeaker positions.

We tested speech with wireless microphones. Feedback threshold was significantly increased (4-7 dB) and speech was perceived as more clear.

That’s great! Hopefully a live-test ona real public-performance will be admitted soon! :-)

Introduction

Believe it or not, many of today’s state-of-the-art operas feature a monitoring system for the main stage, such that singers hear the orchestra more clearly. Not monitoring with visible loudspeakers or in-ear, but discrete loudspeakers for enhancing orchestra’s sound on stage for the singers and artists (not for audience!).

Opera Zurich uses four boundary microphones in the orchestra area to pick up sound, which is routed to some or all of the eight monitoring loudspeakers, depending on the stage design.

Micheal Utz from Opernhaus Zürich had been an Illusonic Test-Balloon Plug-Ins user for a while. When we released the first version of the Clarity plug-in, we received feedback from him on its application for dereverberation. We mentioned that this plug-in was designed for low delay and could be used for live applications as well. This was the start of a fruitful investigative collaboration.

While normally, the opera house stage is extremely busy and time-intensive testing is very difficult, the exceptional situation due to Covid resulted in that the stage was occasionally free for a few hours – ideal for testing! So far we accomplished three goals: 1 measurement of the eight monitoring loudspeakers at different positions of the stage, 2 tuning of the monitoring (EQ and Clarity), and 3 testing by playing back orchestra music. Point 3 turned out very well, everyone in the test agreed that sound everywhere on stage became more clear. A real live test with orchestra and singers is currently not possible, as due to Covid the orchestra can’t play on-site.

More details on points 1 to 3:

1 Measurement

The eight monitoring loudspeakers were measured at different positions on the opera stage with Illusonic CalibrationTool (aka IAP Calibration) software, using an RME Fireface UC interface with measurement microphone connected via ADAT to the monitoring system’s Yamaha mixing console.

2 Tuning

Using CalibrationTool and its headphones auralization feature, Michal Utz tuned the monitoring system via headphones and then tested and refined it with music playback on stage. Once his tuning and testing was finished, he invited us for a test together.

3 Testing

We played different orchestra music and listened from different positions on stage. A good test was also walking around on stage and listening.

Clarity made sound more precise everywhere on stage. There is now hope that with less level live amplified orchestra sound will be more clear for the artists. This would allow monitoring at lower level, which has many advantages, such as:

Less acoustic feedback

Less leakage to audience

Stay tuned for more news on this topic.

More than a year ago, we released IAP’s Immersive Upmix algorithms as a “Test Balloon Plug-In” for music producers and sound engineers. This plug-in works with workstations such as ProTools, Reaper, Cubase, and Logic.

The plug-in has been widely applied worldwide for things such as Dolby Atmos music production, applause upmix, film music, etc. The Test Ballon Plug-Ins Program has brought us a wealth of pro audio feedback. This feedback has allowed us to evolve Immersive Upmix to a great degree.

Now we deliver latest Immersive Upmix, same as in latest plug-in, to our IAP customers via IAP 8.1 Firmware/Software update. Free of charge.

Additionally, the update incorporates many more improvements and bug fixes.

Download the update here.

Change Log (since 8.0..4):

IAP Firmware:

major update to Depth

major update to Immersion

got rid of dry center

new mono upmix option

improved LRC quality

improved Clarity time resolution

IAP Configuration:

added new mono upmix option, and removed dry center

added volume and mute control

kept macOS minimum requirement at 10.6

IAP Calibration:

improved Clarity optimization algorithm

extended Clarity visualization,

added new mono upmix option, and removed dry center

dozens of small improvements

set macOS minimum requirement to 10.11 (from 10.6)

bug fixes
 

https://audioproducteducationinstitute.org/    (video available)

January 19, 2021 
9:00 AM Pacific (12:00 PM Eastern)

This event has been presented by Roger Shively (JJR Acoustics, LLC) APEI’s Automotive Pillar Chair. Following opening remarks, the event features two presentations from Mads Herring Jensen (Technical Product Manager, Acoustics, COMSOL), and Christof Faller (Managing Director, Illusonic GmbH), exploring simulation, visualization, tuning, and auralization topics.
 
Session 1: Modeling Strategies and Techniques in Car Cabin Acoustics (Mads Herring Jensen)
 
Simulation and virtual models plays an important role in the integration of sound systems into the car cabin environment as well as their calibration. This session looks at various modeling approaches and techniques used when assessing these systems. The low to mid frequency behavior is captured with a full wave models, while the high frequency behavior is typically captured with ray acoustics techniques. Emergence of new numerical methods and improved hardware shifts the frequency at which ray techniques are applied. The presentation also discusses boundary conditions as well as source characterization.
 
Session 2: Visualizing, Tuning, and Auralizing  Car Cabin Simulation Results (Christof Faller)
 
A useful method for visualizing the results from an FEA or Ray Tracing models is discussed. Impulse response information is taken directly from a simulation model or generated from amplitude and phase result and imported into an Illusonic tool for reviewing time and frequency data for each point in the results file. For automotive, the number of results point could be microphones set in an array for each listening position. The results data can be grouped for review and comparison to measured data for the purpose of model updates. They can also be grouped and averaged for a virtual equalization as well as auralization. This process will be reviewed and demonstrated.

( Source of most of this text: https://audioproducteducationinstitute.org )

So far, DSP-based room adaptation has been limited to spectral modification. Or, in special cases, advanced room optimizers can reduce effect of earliest reflections, but limited strictly to a small sweet spot.

Illusonic Clarity 3 is an entirely new approach to room adaptation. It reduces reverberance of a room as if more absorbers were installed. Not only in a small sweet spot, but in the whole room. Bass is getting dryer and sound is getting more precise also at high frequencies. This is not only a marketing story. For the technically inclined, we have published an open access research paper on it.

All IAPs ever sold (since 2012) support this update. That’s what we call a time-less high-tech high-end product. Very rare species.

You can download this free-of-charge update here. All your IAP settings are maintained. Right away listen with improved quality after update. Get back to us for enabling measurement-tuned Clarity 3.

Besides revolutionary progress, IAP 8.0 features many other innovations and refinements:

improved remote-tuning, we can listen to your system realistically with headphones with headtracking

“talking display” makes IAP friends with blind people

Immersive greatly improved again

improved precision on many DSP parameters (delay is now sample accurate, …)

iOS remote control app support (via Raspberry PI)

improved multi-room and multi-zone support

improved automation over RS232 and network (via Raspberry PI)

see change-logs below for the many more refinements

Change-Logs (compared to previous latest version 7.1.3)

IAP Firmware & DSP:

Add Clarity 3 with Clarity Tuning

Improved Clarity without tuning (parameters, time-smoothing)

Improved Immersion (new decorrelator & reverb modules, randomization, pre-post processing)

Improved and renamed Immersion High and Size (to Tilt and RT60)

Added “Dry Center” option, to keep dialogue in stereo-movies dry (Depth and Immersion not acting on center and phantom center)

Added (USB) remote control commands for Ad Hoc Settings (balance, subsonic, sub gain, center gain, room mute, room gain)

Multi-room/zones improvements: room mute/gains are now stored permanently, added configurable room name, room mute: prevent that menu is entered unintentionally, during measurement now ignore room mute and room gain

Adhoc Center/Sub Gain: increased resolution from 0.5 to 0.1 dB

Bass/Treble Gain: increased resolution from 0.5 to 0.1 dB

Output Gain Trim range: increased from [-12..12] to [-20..20]

Output Delay Trim resolution: increased from 0.1 to 0.01 ms

EQ gain range: increased from [-18..6] to [-20..20] dB

Sub Overhead range: increased from [-10..20] to [-20..20] dB

Improved precision of all Illusonic algorithms by shifting operating range, such that the dynamic range of 32-bit float is more effectively used

Improved numerics on center extraction for better waveform quality

Added 3 new EQ types. IAP has now 27 different EQ types. The new filters are highpass with q-factor for raw bass driver equalization, and low/high shelving with q-factor for implementing smooth room curves with any slope

Increased Input Delay range to 0..200ms (from 0..100ms)

IAP Calibration control of IAP: all sound settings preset settings are now controlled by IAP Calibraiton (without overwriting any presets), previously only Gain/Delay, EQ, BMGT On/Off were controlled, this enables convenient listening and AB testing with now also Immersive

IAP Calibration control of IAP: “IAP CALIBRATION” is now shown on display while IAP Calibration controls IAP, and, except input and volume change, menus are disabled

Accessibility: added usb command to read out IAP display, updated iap library and iap_tool correspondingly

Improved reset command, such that no big clicks will be on loudspeakers (this happened when one would issue a firmware update without putting IAP to standby)

Improved microcontroller versioning, now pre-release versions are detected and user is prompted to update to final version

Phono in line-in mode now disables RIAA

Fixed input gain (was 2x in dB since IAP 7.1)

Analog-In now has always 20Hz low cut, to remove DC in input (on low levels this could freeze output-gain/volume, due to zero-crossing condition)

Fixed issue of temporary display freeze/corruption 1-2 seconds after IAP boot (with new network card)

IAP Configuration Software:

added Clarity 3 with Clarity Tuning

added Multiroom/Zones settings

added Ad Hoc settings (Balance, Center/Sub gain, etc.)

added support for 3 new eq types

increased input delay range to 200ms

IAP Calibration Software:

introduced dsp params presets, to quickly compare between any different settings

added new import config (.iap) function

added a new panel for Clarity 3 to tune it with measurement data

added Illusonic DSP along with gain/delay, eqs, etc. for real-time tuning

improved integration of Illusonic DSP with headphones auralization

added support for 3 new eq types

replaced phantom function with a more general sum function, to test phase consistency between loudspeakers

added “make mono” button to Auralization/Testing

added support for Bluetooth headtracking to Auralization

improved mean graph legends (now mean type is specified)

renamed Waterfall tab to Decay tab and increased number of range options

added correlation coefficient for crossover optimization

fixed bug, where tone control was not simulated when eq was off

fixed bug, where disable eq function did not work properly
 

IAP Control versatile remote control for our audio processors. Besides main controls (input select, volume, preset, mute), also detail sound settings can be changed. Changes done on IAP directly feed back to IAP Control.

https://apps.apple.com/us/app/iap-control/id1455969349?ls=1

The application is optimized for iPhones and iPads.

We are attending Audio Engineering Society Convention this week. Looking forward to see you there!

AES New York 2019, the 147th Pro Audio International Convention is a R&D and end-user focused event.

Besides being member in several technical committees, we are presenting technical papers on two breakthrough innovations:

1
Science behind Clarity

“Modifying Audio Signals for Reproduction with Reduced Room Effect”
C. Faller, Wed, Oct 16th, 11am

2
Advanced VR-Audio A/B-Format Postproduction

“Spatial B-Format Equalization”
A. Favrot and C. Faller, Fri, Oct 18th, 245pm

If you are not attending, or want to know more details than orally presented, the papers can be downloaded from the AES E-Library:

http://www.aes.org/e-lib/

Update:

We paid the open access fee for the Reduced Room Effect (Clarity) paper, you can download it for free from AES e-lib:

http://www.aes.org/e-lib/browse.cfm?elib=20599

IAP 8.0 with eight major enhancements.

No one is left behind.

Stay tuned…