What is Twizla?

How does Twizla work?

Can I create my own displays?

What are Binaural Beats?

What are Standard MIDI files?

What are OGG files?

Are there any safety considerations?

What is brainwave entrainment?

Is Twizla really free?

Useful links

What is Twizla?
Twizla creates displays with dynamic, evolving colours and visual effects, accompanied by music and sound. Twizla includes a variety of preset displays; you can also create your own displays, which can be saved as Twizla files and exchanged with other users. The flickering patterns create a pleasant, strobe-like effect and can be enjoyed simply as entertainment. However, the flickering occurs in the same frequency range (1 to 20 Hz.) used to categorize electrical activity in the brain (alpha, beta, delta and theta waves), and one of the audio outputs is a Binaural Beat which tracks the flicker rate. Thus Twizla may be used as a tool to experiment with so-called brainwave entrainment.

How does Twizla work?
Twizla displays are based on a grid of rectangular cells. Patterns of cells are defined on this grid (see the screen shot), up to 14 patterns per display. Each pattern is controlled by several envelopes which define how its colours and flicker rate evolve over time. When the display is run, the cells are made to flicker at the frequencies defined by their envelope. Many of the visual effects are achieved by applying similar envelopes to patterns, slightly offset either in time or amplitude. Sound output from Twizla is from one or more sources:

1) A Binaural Beat, generated by Twizla, tracking the flicker rate of a designated pattern.

2) A MIDI file associated with the display.

3) An OGG file associated with the display.

Can I create my own displays?
Yes. Twizla contains an editor for creating your own displays. You can build a display from scratch, or base your design on an existing preset. Twizla can also scan the content of a MIDI file and automatically create a display based on the musical content of the file. The parameters for displays you create can be saved as Twizla (.twz) files.

What are Binaural Beats?
The visual flickering in Twizla uses frequencies in the range from 1 to 20 Hz, well outside the normal audio frequency range. A tone played at these frequencies would be perceived as a series of clicks.

Binaural beats simulate these low frequencies by playing an audio frequency stereo tone, with the frequency of the two channels differing by the required low frequency. For example, using Middle C (261.63 Hz.) as the carrier frequency, if the left channel plays 256.63 Hz. and the right channel 266.63 Hz., a binaural beat at 10 Hz. will be produced. Low frequency (1 to 5 Hz.) beats are perceived as a stereo phasing effect, high frequency ones as a tremolo effect.

Twizla allows you to select a carrier frequency for the beat, and also to designate one of the patterns as the controlling pattern. The beat frequency will then track this pattern.

Note that binaural beats are designed for headphone listening at very low volumes. Note also that the effect will be lost if you have any chorus-type effects applied to the wave output of your soundcard.

What are Standard MIDI files?
MIDI files are a popular format for storing music performance data. Unlike files in MP3 or Ogg Vorbis format, they do not store an audio recording; they contain instructions (e.g. note pitch, velocity, tempo data) for recreating a performance, rather like a score, and will usually be many times smaller than an equivalent audio recording.

The information contained in a MIDI file is sent to the MIDI synthesizer section of your soundcard to recreate the performance. Of course, the performance will vary according to how your soundcard is set up. MIDI file playback from Twizla assumes that your soundcard is loaded with a GM (General MIDI) instrument set. GM defines a standard instrument set where, for example, MIDI Channel 0 is assigned to a piano instrument, MIDI Channel 10 is for a drum set etc.

Several MIDI files are supplied to accompany Twizla's preset displays, and there are numerous sources of MIDI files on the internet (see Links). Twizla has the capability to scan a MIDI file and create a display based on the data in the file - a kind of MIDI 'visualization'.

What are OGG files?
Ogg Vorbis is an audio compression format, comparable to other formats used to store and play digital music, such as MP3, VQF, AAC etc. It differs from other formats in that it is completely free, open, and unpatented. Its file size is also smaller than MP3, and it sounds better!

Ogg Vorbis already enjoys widespread software player support and is compatible with several major hardware players. For more information about Ogg Vorbis, including details of currently available encoder applications, see the Ogg/Vorbis website.

Safety considerations
Twizla is designed for entertainment. No specific claims are made as to the medical or other effects of running this software. Twizla does produce visual flickering that may be uncomfortable for some people. As with any source of flickering light you should be cautious, particularly if you:

have ever suffered from any form of seizure disorder or epilepsy,

have suffered serious head injury or concussion,

are taking psychoactive drugs (tranquilisers, stimulants etc.), or

are sensitive to bright or flickering light.

Also note that the binaural beat sound output is intended to be listened to through headphones, at a low volume. Playback through loudspeakers, or at a high volumes, may at best be annoying to others and, as with any loud sound, may damage your speakers and possibly your hearing.

What is brainwave entrainment?
Brainwave entrainment is based on the theory that certain recognizable patterns of electrical brain activity are associated with different states of mind. For example, brain activity characterised as 'Alpha rhythms' (7 to 13 Hz.) is associated with calm, reflective states. The theory proposes that sensory stimulation at the desired frequency can help the mind to reach the corresponding state. Various devices and techniques are marketed: light spectacles, hemisynch™ sound etc.

No claims are made for Twizla in this regard; however, if you'd like to experiment, Twizla can create displays to help. There is a full (and fair) discussion of entrainment theory at realization.org.

Is Twizla really free?
Yes, this version of Twizla is released as freeware, and may be freely used and distributed. The copyright, however, remains with me, and a future commercial release is possible; I do have development ideas. If you have any comments or suggestions, please feel free to contact me. Donations are very welcome (see the PayPal Donate button at the top of this page). A donation, or an implemented development idea, would entitle you to a free copy of the commercial version, should one become available.

To read more about me, the author of Twizla, please visit the about page. To contact me, please use the form on the contact page.

Useful links:
There are many sources of MIDI files on the internet, for example The Classical Archives is a long-established provider of classical music MIDI files.

Twizla creates displays from MIDI files. To see this the other way round, try MIDImage from www.genjerdan.com. MIDImage creates MIDI files from the colour information in a BMP or JPEG image.

For more information about photic stimulation, binaural beats, brainwave entrainment, and bio-feedback in general, see the Mind Machine FAQ at Realization.org.

For more information about Ogg/Vorbis - what it is and why it is needed - see Vorbis.com.