The Model 9739 Stereo Vitalizer MK2-T from SPL is a tube-enhanced, audio processing device that applies psychoacoustic and audiometric principles to achieve a sonic improvement while affecting the sound. The Vitalizer processes only the original signal and generates no artifacts.

SPL-created filtering techniques highlight the richness of the audio signal in all its detail, while the interactive parameters make it possible to alter the sound in a musical and effective way. This unique combination of filtering and usability enable you to make music production more stimulating and natural. The Stereo Vitalizer was designed to make music and speech more clearly distinguishable and comprehensible, with loudness more intense, while widening the overall soundscape.

The Vitalizer filter network was designed to assist the sound engineer in achieving an objective improvement while optimizing sound. The unit assists in creating more detail, more transparency, more loudness and, if needed, an expanded low-end foundation. Regardless of whether you process a single channel or a sum of channels, this MK2-T is designed to improve your sound.

The Stereo Vitalizer Mk2-T is the next generation of Stereo Vitalizer, with an updated circuit design which adds newer filters and controls to the existing parameters. It is designed for mastering, post production work and sound reinforcement.

The frequency spectrum is usually divided into three frequency bands: highs, mids and lows, all of which are provided in the Vitalizer, even though, as opposed to conventional usage, low and mid filter settings are interrelated. The high frequency control allows processing of high frequencies and harmonics. You can adjust each of the three frequency bands separately and control the intensity of the process independently.

One of the Vitalizer's main features is the unmasking of overlapping sounds or sonic clarification. The way this works is, in principle, opposite to the way compression formats (MP3, etc.) do; instead of deleting allegedly unnecessary information, it enhances it. In order to do that, the Vitalizer takes into account the perception of a frequency in relation to its volume. By shifting louder frequencies slightly in time, softer and formerly overlapping sounds are "unmasked" and made audible, enhanced. The audible effect of unmasking could be described in general terms as more clarity and depth in a mix. Lows sound more powerful and better defined, mids more focused and differentiated and highs more vivid and brilliant. It can be used on individual channels to emphasize the sound character of instruments or vocals. The clarity and definition are achieved and presence in the mix is improved.

Another characteristic of the Vitalizer's sound optimization process is the adaptation of the sound spectrum to the non-linear sensitivity of human hearing. This phenomenon was audiometrically proven in the 1930's thanks to the equal loudness contours, also known as the Fletcher-Munson curves, named after their discoverers. According to these curves, the human ear is most sensitive to mid frequencies, i.e. to the frequency range of speech. As a result, frequencies below 200 Hz and above 6000 Hz need reinforcement in order to achieve a well-balanced auditory impression - frequencies between 6 kHz and approximately 11 kHz are perceived as being 5 dB softer, for example. The Vitalizer uses the equal-loudness contours to balance the frequency spectrum according to human hearing, which can in turn improve loudness. As a result, individual elements of a mix can sound more present without an actual increase in level. At the same time, the sum signal also benefits from the Vitalizer processing since it can achieve the same loudness with less sound pressure level, unlike raising equalization which actually boosts audio level.

Inputs and Outputs Instrumentation Amplifier, electronically balanced (differential),transformerless 
2 x XLR Balanced inputs and outputs 
2 x TRS Balanced inputs and outputs 
Nominal Input Level: +6 dB 
Input Impedance: 22 kOhms 
Output Impedance: < 600 Ohms 
Maximum Input Level: +20 dBu 
Maximum Output Level: +20 dBu 
Minimum Load Ohms: 600 Ohms 
Relay Hard Bypass: yes 
Power Fail Safety: yes
Measurements Frequency Response: 20 Hz to 100 kHz (100 kHz = -3 dB) 
EQ Frequency Range: 20 Hz to 22 kHz 
CCMR (Common Mode Rejection): >-86 dBu @ 1 kHz 
THD & N: 0.01855 % @ 1 kHz 
S/N CCIR 468-3: -85 dBu 
S/N A-weighted: -99 dBu
Power Supply Torroidal Transformer: 15 VA 
Fuse: 315 mA (slow blow) 
Ground-Lift Switch: Yes 
Voltage Selector: Yes
Dimensions (W x H x D) Standard EIA 19" / 1U 
19.0 x 1.7 x 9.3" (482 x 44 x 237 mm)
Weight 7.8 lb (3.4 kg)
Packaging Info
Package Weight 10.9 lb
Box Dimensions (LxWxH) 21.0 x 14.8 x 4.9"

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