More information on the system architecture can be found here.
The delay system is a digital replica of one constructed by Pauline Oliveros, with the left channel cross coupling back on itself, and the right channel feeding back to the left, with an eight second delay. The model is outlined in more detail in the article below:
Tape Delay Techniques for Electronic Music Composers
- The first being the built-in Waveform Generator, which holds a set of four oscillators, one side demonstarating Amplitude Modulation synthesis, the other side Frequency Modulation synthesis. There is also an available white noise source with a filtering effect that is routed to the same amplifier as the FM side of the oscillator.
- The second being the user's own input, be it the hardware microphone, an audio/instrument interface, etc. The browser works automatically with your computer's global audio settings, any changes to audio I/O are all made in said settings.
These two inputs can be used in tandem.
- The Tape Delay Feedback control sliders allow you to control the amplitude of each respective feedback element at play in the system (these mimic the line amplifiers used by Pauline in the original system); they control the depth of the cross coupled delay, and the depth of the right channel (from tape machine #2) back to tape machine #1. It is HIGHLY ADVISED that you be careful with these sliders!!! This is a feedback environment, things can (and will) get loud very quickly if you are not careful! It is also advised that you consult the article mentioned above to gain a better picture of what the system is doing.
- The system is sensitive! You are dealing with a lot of looped and delayed feedback! If you find that the system has 'bottomed out' (ie. stopped making all sound, making unbelievably loud and continuous sound), it is likely because the feedback was overwhelming and it collapsed on itself. To clear the system, simply lower the Tape Delay Feedback Sliders and it should be corrected.
- It is also suggested that you have a listen to music that utilize this type of system. Pauline Oliveros' Mnemonics I-V and I of IV are great examples (as are several of her other works in this period). You may also refer to pieces such as Saxony by James Tenney; and though it employs somewhat different techniques, Poppy Nogood and the Phantom Band by Terry Riley (the B-Side to A Rainbow in Curved Air).`
- To use the audio recorder, simply push the REC button to start recording, when finished push STOP. You can then hit play and listen to your recording, this allows the file to buffer and render. Once that is finished, a download icon will appear on the audio player, and you may download an .ogg file of your recording.
- Lastly, it is suggested to let the system be itself. Experimentation is key, but sometimes stepping away and letting things unfold is when magic can happen. Remember, in feedback systems, not every action has an effect, and even the slightest action can have massive impacts.
MIDI Instructions/Maps This instrument is MIDI compatabile via the Web MIDI API (currently only available in Chrome). It is a plan to enable MIDI assignments, but it is currently not available. If you would like to attach a MIDI controller, you may consult the MIDI Info button and edit/map your controller to the proper CC assignments.
This currently does not work (or at least well) with mobile devices. The goal of this was to explore the use of Chromebooks as musical environments, however I am seeing to implement a mobile friendly version in the future.
Here is a list of the MIDI CC Numbers and the controls in which they are assigned:
CC 2 - Input Volume (User Input)
CC 3 - AM Harmonicity (blue label)
CC 5 - FM Harmonicity (red label)
CC 6 - Cutoff (Noise Source)
CC 8 - Depth (Noise Source)
CC 9 - Cross Coupling Depth (T-D Feedback)
CC 12 - R to L Depth (T-D Feedback)
CC 14 - AM Frequency (blue label)
CC 15 - AM Fine Tune
CC 16 - FM Frequency (red label)
CC 17 - FM Depth
CC 18 - Attack (not available)
CC 19 - Decay (not available)
CC 20 - Sustain (not available)
CC 21 - Release (not available)
CC 24 - AM Squ ---- Saw (blue label)
CC 25 - AM ---- FM
CC 26 - FM Squ ---- Saw (red label)
CC 27 - OFF/ON (Noise Source)
CC 33 - OFF/ON (User Input)
This system employs a few classic synthesis techniques that can serve as an introduction to deeper concepts. Modern analog synthesis (also known as modular synthesis) began in `
Regardless of tradition, the sound sources of each brand of synthesis remain the same, as simple waveforms (sine, square, sawtooth, triangle) generated by oscillators. Each of these waveforms possess different characteristics in terms of shape and existing partials, and each bring their own powers to the table. Here is a solid breakdown of each waveform and its qualities.
In this app, the Waveform Generator allows for two different, yet common, types of synthesis, Amplitude Modulation (AM) Synthesis, and Frequency Modulation (FM) Synthesis. This is a highly simplified version of the Buchla Model 261e. The module has a carrier frequency (the principal pitch) and a modulation frequency (the one that changes the sound). Depending on if you choose AM or FM, the modulation frequency acts differently upon the carrier. Simply put, in AM Synthesis, the gain of the carrier is modifed, in FM Synthesis, the frequency is modified. The results of these modulations however, go much deeper. Click these links for more information on AM Synthesis and FM Synthesis.
The Noise Source is a common addition to any modular synthesizer. The role of noise is to introduce a tunable signal into the system. While there are several different kinds of noise, this system employs a white noise generator with a filter. White noise is equal energy per frequency, and from there you can read more on noise types. Because noise is equal parts energy, you can use it to modulate a number of other modules, and tune it to your desired result through filtering and other means. In the case here, it is not patchable to other parts of the system, but exists as another sound source, but still has a filter.
The filter is the piece that can focus the frequencies or partials of a sound. When multiple waveforms are mixed together, many more waves are created, called resultant tones (or sometimes difference/additive tones). This mix of simple waveforms is what makes the sound of the synthesizer so interesting. One method of controlling these tones, is through the use of filtering, also called subtractive synthesis. Filtering technique is a very rich subject, as many different filters exist, can be controlled in different ways, and ultimately rely on the ear of the performer to achieve the desired sound. In the case of our filter in the Noise Source module, it stands as a low-pass filter (the lower the knob is, the lower the frequencies that are passed through). Read more on Subtractive Synthesis
The ADSR (attack-decay-sustain-release) Envelope is what shapes the waveform in terms of amplitude (volume). For example, when a piano key is struck and held, there is a ramp up to the peak of the sound (attack), the time of the run down from peak to the sustain level (decay), the level when the note is held (sustain), until the key is released (release). In the case of the piano, there is a very sharp attack, a long steady decay, technically no sustain (as the sound is continuiously decaying), and a sharp release when the finger is taken off the key. Many instruments and/or performers, including the synthesizer, have control over the envelopes they generate. Read more information on envelopes.
There are numerous resources available online to learn more about these techniques, but in my opinion, the most fruitful resources are Electronic Music Systems, Techniques, And Controls By Allen Strange (available as e-book or used in many outlets); and Miller Puckette's Theory and Techniques of Electronic Music.The latter centers on using the free, open-source software PureData, to learn about electronic music techniques, and is highly recommended (and always free).
Tape Delay Feedback