The 9530 Tube Vitalizer for mastering from SPL is a multi-capable audio processing unit that, with its combination of tube, coil and transistor circuitry, can be used for mixing, mastering and restoration of sound. The Vitalizer offers more than simply equalization. It includes additional processing circuitry to maximize efficiency, and is designed to be simple to use as well, both in single-channel and subgroup processing. It is also a capable unit used in refining summing signals.
The Tube Vitalizer is designed for discerning applications in professional mixing, mastering and restoration. All effect intensities, potentiometer values and characteristics are engineered to be optimized for refined requirements. The sound processing of the Tube Vitalizer is split into two sections: on the left side you find the controls of the Vitalizer circuitry and the compressors, while on the right side there is the tube section, which can be used independently of the Vitalizer section as a high-quality, low-noise tube-line preamp.
With the Tube Vitalizer you can chose between familiar RC filters (condensers) or the often very interesting, warmer sounding LC filters (coils) for filtering bass and high frequencies. The sonic differences are similar to those of tubes compared to semi-conductors, and they are sometimes even more dramatic. LC filters can saturate in a similar way to tubes, producing a pleasant harmonic structure. LC filters activate a passive coil network which is integrated into the active filter path. Bass processing, for example, results in a subjectively more powerful sound with more sustain. LC filters not only affect the Bass section, but also the mid-damping behavior of the Hi-Mid Tune so that low-mid frequencies in particular benefit from that circuitry. The sound often gets more punch and directness. An LC filter can also be added to the high-frequency filtering to improve presence in the mid-range, which is ideal for vocals. Especially in mastering applications, the LC filters add another tonal dimension to your processing repertoire.
The second innovation in the Tube Vitalizer design is the inclusion of two compressors, one for the bass and one for the top-end filtering. These compressors allow compensation for level changes due to the processing. Alternatively, they can also be used for sound shaping of course. The compressors operate with a soft-knee characteristic to provide unobtrusive results, while Attack, Release and Threshold are pre-set for their frequency range (bass or top-end processing). This results in simplified ease of use and exacting level control even when intensive processing is applied.
The Tube Vitalizer is equipped with both electronically balanced solid-state and tube output stages, and you can switch from solid-state to tube operation by the push of a button. Now you can add tube sound to your mix and directly compare it with the solid-state sound. The tube stage is an original AEG design from 1955. It utilizes three tubes. One of them is used as a differential stage and carefully enhances the stereo base. This effect complements the tube sound itself, and it delivers more depth and transparency, especially in the mid-range. The tube stage also reduces crosstalk to 54 dB, which is typical for vinyl cutting. One characteristic of vinyl sound versus CD specs is a more natural sound stage; there are no coherent sounds in nature that have a channel separation of about 90 dB like that of a CD.
The tube section provides a frequency bandwidth from 30 Hz to 30 kHz. Standard designs often limit the bandwidth, which gives a limited impression of frequency bandwidth – and that may often be associated with “tube sound.” The Vitalizer’s tube sections does not limit frequency response. If you carefully listen to reverbs of vocals or snare (or simply put on pink noise), you can easily identify the harmonic structures tubes add.
The Tube Vitalizer is built using high-quality ALPS potentiometers, which combine reliability with a very usable tactile response, and the mechanism has enough resistance to make unintentional movement unlikely. Practical VU meters show either input or output levels, making it easy to compare levels when extensive filtering is required. The Tube Vitalizer is equipped with both XLRs and stereo jacks for balanced operation. We use the SSM input and output stages, which feature laser-trimmed resistors, providing a common-mode rejection of better than 87 dB. Mono jacks may be used for unbalanced operation without level change.
One of the Vitalizer’s main features is the unmasking of overlapping sounds. The way it works is, in principle, opposite to the way compression formats (MP3, etc.) do, in that 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. 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. Furthermore, it can be used on individual channels to emphasize the sound character of instruments or vocals. The clarity and definition achieved guarantee an adequately perceptible presence in the mix.
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 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 in turn improves 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.