Niveau Filter with shelving High EQ and elliptical Equalizer for Stereo Mastering
The Niveau Filter W794 is a special combination of different equalizers for global corrections of the frequency response with stereo mastering or mixing. The three filter sections of the W794 allow global treatment in versatile ways by controlling the high-low balance and by boosting or cutting the mid range as well as corrections at the upper limit of the audio band. Such filters are proven and tested for their behavior in practice for decades, since they where part of the AT versions of the large format console master sections ever since. In difference to the Niveau Filter W795 that offers similar features, the W794 adds an elliptical equalizer that allows to center the bass range of a stereo mix by a frequency depending mono matrix. This version is of advantage, if no M/S matrix that includes an elliptical equalizer, is installed in the mastering system.
The niveau filter W794 is available with boost/cut ranges of +/- 16 dB, +/- 10 dB, or +/- 6 dB. The image shows the +/- 16 dB version.
The HI-EQ ist a soft shelving equalizer for global correction at the upper end of the audio band. The steepness of the filter is 6 dB/oct.. A frequency control determines the limit frequency of boost or cut between 4 kHz and 35 kHz.
The Niveau Filter of the W794 is identical to the filters of the other niveau filter versions W795 and W795b. These filters have been used since the 1950th in German broadcast network consoles. The device was designed to correct room specific peculiarities. In our application of the principle, we use two different controls, as described above. Over the years, the characteristics of the curves have been optimized for use with global corrections of final mixes.
The Boost/Cut Filter affects the relation between the high/low range and the mid frequencies. Turning the control to the right increases high and low frequencies, while cutting reduces high and low simultaneously. The neutral frequency is 800 Hz, the curves are optimized for that kind of regulation and have a special S shape that leaves the mid range unchanged while affecting high and low in an appropriate relation.
The Balance Filter corrects the high/low relation and leave the neutral frequency of 800 Hz unchanged. In one direction of the control the filter boost high frequencies and cuts low frequencies. The other direction reduces high frequencies and boosts low frequencies. The curves are also adapted to this regulation and have a weakly pronounced s shape with corner frequencies close the 800 Hz.
Das Gerät ist in symmetrischer Technik ausgeführt und kann wahlweise mit hochwertigen Ringkern-Ein- und Ausgangsübertragern oder mit elektronisch symmetrischen Ein- und Ausgangsverstärkern bestückt werden. Der maximale Pegel beträgt + 30 dBu. Durch die Double-Balanced-Technik, bei der der gesamte Signalweg in symmetrischer Technik ausgeführt ist, beträgt auch der interne Headroom + 30 dBu.
The elliptic equalizer reduces the stereo base width below an adjustable edge frequency and can reduce mono compatibility problems caused by phase reversed signals in both stereo channels or time shift effects at low frequencies. Since human ear is not able to locate anything below 300 Hz, reducing the base width below that range causes no audible effects but 'centers' the bass range to improve the mono compatibility. The section increases the crosstalk with a steepness of 6 dB/octave. The frequency control is calibrated in that frequency that causes 15 dB crosstalk. The control range starts at 25 Hz and reaches up to 2 kHz. A setting above 300 Hz will be audible; however, may result in a better compromize of the particular mix..
Each section has a bypass switch. The device is internally and externally balanced. Input s and outputs can be balanced and grounded (electronically balanced) or balanced and floating, using oversized torodial transformers. The maximum level is + 30 dBu. Due to the internally balanced circuitry, the internal headroom is also + 30 dBu. The Niveau Filter W795 has a dynamic range of more than 120 dB RMS. The hard bypass switches the entire device in and out.
The Niveau Filter with High-Low Equalizer W795 is an alternative to the W795, if there is no other device installed that offers an elliptic eq.
The Niveau Filter W795b is almost identical to the W795 but adds steepness selection for the high and low equalizers.
Additional modules for global corrections are the Stereo High-pass Low-pass Filter with Notch Filter W792m and the Stereo High-pass Low-pass Filter with Phase Correction W790.
The module is a V700 standard device that fits into all standard frames.