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E
simply faulty designs which refuse to work properly even when receiving correct ID data.
The ULTRA-DYNE PRO can be equipped with an AES/EBU interface as an option.
4.3 Artificial generation of harmonics
In the year 1955, the American Charles D. Lindridge invented the Exciter, a unit that "excites" upper harmon-
ics, and presented a unit for "improving the sound of music and speech". He enriched signal sources with
artificially generated upper harmonics and found that sound quality, transparency and the perceived posi-
tioning of musical instruments could be improved substantially using this effect. He was granted an American
patent on his circuit design under the number US 2 866 849.
Compared with today's technology, Lindridge's device was far from mature. However, it already incorporated
all of the essential features of modern circuits. Recent scientific findings on the psychological aspects of
acoustics and advances in technology have since led to new and improved devices.
The digital reproduction of this harmonic generation process in a "virtual" Exciter also opens whole new per-
spectives for the control of the spectral distribution of the generated harmonics.
Vacuum tubes also generate harmonics due to nonlinear distortion. The harmonic structure of this distortion
is distinctly different from that of the distortion generated by overdriven transistor circuits. The tube-specific
sound is subjectively perceived as warm, pleasant and "harmonious". The ULTRA-DYNE PRO is capable of
simulating a variety of tube types, each with their own typical acoustic characteristics.
4.4 Tube technology
When observing the development and trends associated with audio engineering, it quickly becomes apparent
that tubes are experiencing a true renaissance. And that despite the fact that today's amateur musicians take
digital effects devices and recording media for granted, and that increasingly affordable digital mixing desks
are appearing among the equipment of semiprofessional studios. Manufacturers are constantly experimenting
with new algorithms in order to extract maximum performance from the DSPs (digital signal processors), the
heart of digital audio systems.
Despite that, many audio engineers, especially highly experienced ones, still use old and new tube equip-
ment. They are often willing to accept the comparatively high noise levels of their "old jewels" in order to take
advantage of the typical warm sound of this equipment in their productions. As a result, a number of micro-
phones, equalizers, preamps and compressors based on tube technology can be found in the recording and
mastering sectors today. Digital simulation of tube technology has created a way to enjoy the best of both
worlds and compensate for their typical disadvantages.
The use of tubes in a recording studio should not be equated with their function in an overdriven guitar amplifier,
however. In a guitar amplifier, the extreme saturation of the tube causes a complete, intentional transformation
of the input signal which often goes hand-in-hand with a serious increase of the noise level. A far more subtle
approach is generally required in a studio environment. In this situation, the tube circuits give the signal a lively,
punchy character. In many cases a higher subjective loudness is also attained in relation to the unprocessed
signal, i.e. the perceived volume is higher at the same level. This results from the limiting of the top of the
dynamic range of the input audio signal by the saturation of the tube circuit, thus reducing the amplitude
difference between the softest signals and the loudest. An increasing saturation of the tubes thus results in a
gentle compression of the entire usable dynamic range.
A similar effect occurs when analog tape machines are overdriven. This so-called tape saturation effect also
causes a slight compression of the recorded audio material, as well as generating additional harmonics.
The ULTRA-DYNE PRO uses a Tube Emulation which delivers a sophisticated, authentic effect and which was
developed as a result of investigations of a variety of tube circuit characteristics. This newly developed
algorithm is intended to provide a subtle refinement of the sound, not the powerful distortion common to
overdriven guitar amplifiers.
4. TECHNICAL BACKGROUND
