Audio Engineering Interactive

Settings

Sound

Start quietly, then adjust the system volume. Sound only starts with the speaker button in a module. A limiter at the output catches level peaks. In the harmonic series the level refers to the RMS value: if you flip individual phases, the waveform changes a lot but the sound hardly at all.

Level calibration (dB SPL)

Applies to the modules “Decibels and phons” and “Masking and masked threshold”. The level ratios between the tones are always right, the absolute dB SPL values only after calibration: play the calibration tone and set the reference or the system volume so that a sound level meter at the headphones or listening position reads 94 dB. Do not change the volume afterwards. Without calibration and with arbitrary headphones, the threshold of hearing and the isophones are only approximate.

MIDI keyboard

Applies to the harmonic series: a key sets the fundamental f₀, the sound plays while it is held. With several keys the last one pressed wins. Pitch bend detunes by up to ±2 semitones. The setting is remembered; a keyboard plugged in later is detected automatically.

Privacy policy

This website is a teaching resource for audio engineering. It works without registration, cookies or third-party analytics services and loads no content from third-party servers; fonts, scripts and graphics are delivered from here. For anonymous visitor statistics I use a self-hosted Matomo without cookies. Personal data is only processed to the extent described below.

Controller

Jan-Hendrik Kramer
Caprivistr. 1
49076 Osnabrück
Email: jan@jhkramer.de

Hosting, server log files and access statistics

The website is hosted by ALL-INKL.COM – Neue Medien Münnich, owner René Münnich, Hauptstraße 68, 02742 Friedersdorf, Germany. When you open a page, your browser transmits technically necessary data to the server, which is recorded there in log files: shortened IP address, date and time of the request, the requested address, the previously visited page (referrer), browser and operating system (user agent), amount of data transferred and status code.

The IP address is shortened before it is stored: the last two blocks are set to zero (11.22.33.44 becomes 11.22.0.0). This means it is no longer readily possible to identify your connection. The log files are deleted automatically after 190 days.

From these shortened log files the host generates simple access statistics (for example the number of requests per page and day). They are only accessible to me, are not combined with other data and serve to see which modules are used.

The data is processed to deliver the website, to ensure its secure and stable operation, to analyse errors and to improve the resource. The legal basis is Art. 6(1)(f) GDPR; the legitimate interest lies in the technically error-free and secure operation of the website and in knowing how it is used.

A data processing agreement pursuant to Art. 28 GDPR has been concluded with ALL-INKL.COM. Under it, the host processes the data only on my instructions and in compliance with the GDPR.

Further information on data processing by the host can be found in the privacy information of ALL-INKL.COM at all-inkl.com/datenschutzinformationen.

Visitor statistics with Matomo

To see which modules are used and how often, I use the open-source software Matomo. It runs on my own web space at ALL-INKL.COM (see above); the data is not passed on to third parties, including the developers of Matomo.

Matomo works here without cookies and does not read browser features such as plugins or screen resolution. When a page is opened, the following is recorded: the IP address shortened by two blocks (11.22.33.44 becomes 11.22.0.0), the page opened without parameters, date and time, the previously visited page (referrer), browser, operating system and device type, the browser language and the approximate country derived from it. Several page views within one day are grouped into one visit using a daily changing, irreversible hash; you are not recognised across days.

The statistics are only accessible to me and serve to improve the teaching resource. The legal basis is Art. 6(1)(f) GDPR; my legitimate interest lies in knowing which content is used. Raw data is deleted after 180 days; after that only aggregated figures without personal reference remain.

If your browser sends “Do Not Track” or “Global Privacy Control”, nothing is recorded. You can also object to the recording here; your objection is noted in your browser’s local storage:

Visitor statistics are switched on for this browser.

Storage in the browser

The website sets no cookies. To keep your settings, it stores the chosen colour scheme and the sound output settings (volume, calibration, MIDI on/off) in your browser’s local storage (localStorage). This information stays on your device and is not transmitted to the server. It is only stored when you change the respective setting and is required for the function you requested (Section 25(2) no. 2 TDDDG). You can delete it at any time in your browser settings. If you object to the visitor statistics, this is noted there as well.

Sound output and MIDI

Sounds are generated entirely in your browser (Web Audio API). A MIDI keyboard is only accessed once you switch MIDI on in the settings; your browser may then ask for your permission. MIDI data is only evaluated locally and is not transmitted. No microphone is used.

Contact by email

If you send me an email, I process your address and the content of the message to answer your enquiry (Art. 6(1)(b) GDPR where it concerns entering into a contract, otherwise Art. 6(1)(f) GDPR). The data is deleted as soon as it is no longer needed for this purpose and no statutory retention obligations apply.

Your rights

You have the right of access to the data stored about you (Art. 15 GDPR), to rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18) and data portability (Art. 20). You can object to processing based on Art. 6(1)(f) GDPR on grounds relating to your particular situation (Art. 21). Simply contact the email address given above.

You also have the right to lodge a complaint with a data protection supervisory authority (Art. 77 GDPR), for example the State Commissioner for Data Protection of Lower Saxony in Hanover.

Last updated: November 2026