Sonnox Oxford EQ & Filters Operation Manual Version 1.
1. Introduction The Oxford EQ and Filters plug-in draws on the considerable experience in professional audio and studio systems earned by the Oxford Team, the team that designed the OXF-R3 console system. The Oxford EQ plug-in is based on the OXF-R3 EQ section and provides a truly professional EQ processor for Pro Tools, VST and Audio Units users. The Oxford EQ is a fully functional 5-band application with selectable shelf settings on LF and HF sections.
2. Operation 2.1 Equaliser Design Programme equalisers have expanded beyond their original use as distance correction devices for film and vision, into highly creative tools that represent a leading part of the sound engineer’s artistic palette. A great many EQ designs have been developed over the years that have been attributed with qualities that lend themselves to particular uses and sounds.
2.2 ‘Front Panel’ Controls The EQ and Filter controls are presented in a user-friendly layout, and the function of most of the knobs and switches should be immediately obvious. Full information on each control is provided in a later section of this manual: Description of Controls. Note the numeric displays for each rotary control. These provide instant feedback of your EQ and Filter settings, in addition to the graphic ‘response display’ provided at the top of the plug-in layout.
2.3 Response Display The upper area of the Oxford EQ plug-in is taken up by the EQ and Filter response display: In addition to more conventional knob control, the EQ can be controlled from this graph if the ‘drag handles’ option is selected via a drop-down options menu that appears when you click the Sonnox button in the top left of the display. By default, the drag handles will be shown on the graph.
By default the vertical scale of the graph automatically adjusts itself to contain the yellow response line or all active handles, whichever is the bigger. The ‘+’ and ‘-’ buttons on the left hand side of the graph can be used to increase or decrease the scale of the graph. The default graph scale, and other options, can be changed by clicking the Sonnox button and selecting the Graphs entry on the drop-down menu. Note that the response graph setup is saved and restored across instantiations. 2.3.
2.3.2 Switching a Section In or Out Double clicking on a graph handle will toggle the section IN button – You can also double click and drag without having to click a third time. Double clicking with the Control Key down – This will apply the toggle to the handle hidden behind the top one, if there is one.
2.3.5 Changing the Q or Overshoot There are three ways to do this: If your mouse features a scroll wheel, scroll up or down to broaden or tighten the Q or overshoot. For finer resolution, use scroll + Shift key. If there is a right button on your mouse, drag the handle up or down with the right button. For finer resolution use right button drag + Shift key. Otherwise, use left button drag + ‘alt’ key up or down to broaden or tighten the Q or overshoot.
The following sections provide a description of each EQ type: 2.4 Bandpass Sections 2.4.1 EQ Type 1 This style has minimal Gain / Q dependency, smaller amounts of boost or cut still have relatively high Q, and it is therefore precise and well defined in use. However it is sometimes difficult to obtain overall EQ fill on combined sources and subtle EQ on vocals and the like, as the user needs to adjust the Q control to maintain an effect when the gain is changed.
2.4.2 EQ Type 2 Type 2 EQ is exactly similar in boost as Type 1, but has constant Q responses in cut. This is the only type of EQ offered in the Oxford plug-in that has unsymmetrical curves. Therefore EQ applied in a boost cannot be readily reversed by cutting afterwards.
2.4.3 EQ Type 3 This style of EQ has a moderate amount of Gain / Q dependency whereby the Q reduces with gain. This provides the EQ with a softer characteristic as EQ is progressively applied and since the effective bandwidth is increased for low gain settings, it sounds louder and more impressive when used at moderate settings. The gentler Q curve also lends itself better to overall EQ fills and more subtle corrections in instrument and vocal sources.
2.4.4 EQ Type 4 EQ Type 4 builds on Type 3, using a far greater Gain / Q dependency which maintains an almost equal area under the curve in the boosted region with gain control operation. It is extremely soft and gentle in use and is most suited to overall EQ fill and character modification for mixed parts (and completed mixes) where subtle changes in overall impressions are required.
2.5 Shelving Sections In the Oxford EQ, the highest and lowest bandpass sections can be independently switched to provide a shelving function. Although shelving functions are often considered elementary, they are by no means all the same, and their importance to the sound engineer should not be underestimated. Various types in common use are considered to favour certain types of use or are considered preferable by users of differing persuasions.
2.5.1 Shelving Overshoot Control (HF shelf Q control) When the HF shelving function is selected, the Q control provides control of the ‘overshoot’ function. With the Q control set to minimum (yellow plot) the section has no overshoot and performs a basic and accurate shelving function. This is most like the responses provided by the original SSL 4000 EQs and many other outboard units often described as ‘clean’ EQs.
The purple plot shows the effect of the Q control in its mid position. This produces a gain loss of around 10% (of the boost gain) in the overshoot region and further defines the effect described above. This setting provides a response most like the legacy Neve designs and their derivatives, and the later SSL G Series EQs.
2.6 GML 8200 Emulation In addition to the four Oxford R3 EQ types, a further GML 8200 emulation EQ is provided, currently only for Pro Tools TDM/HD users. With the GML EQ, the Q controls in the LF and HF sections are inoperative when shelving is selected. Any previous setting of the Q controls will be restored when the EQ is reset to any of the appropriate GML 8200 band pass or Sonnox Oxford EQ selections. 2.6.
GML 8200 Bandpass GML 8200 band pass section responses, showing full frequency ranges from 15Hz to 26KHz with +/-20dB gain ranges.
3. Description of Controls The plug-in’s user interface consists of two sections for EQUALISATION and FILTERING functions. Response Display Displays the currently active EQ and filter response curves. The graph will rescale to match the current sample rate.
LF and HF Filter Sections The LF and HF buttons switch the relevant filter in/out. The numeric button above determines the slope of each filter from 6dB – 36dB/octave in 6dB/octave steps. The rotary control determines the filter turnover frequency. LF, HF, LMF, LMF Sections The FREQ control sets the centre frequencies for bandpass or turnover frequencies for shelf curves. The Q control determines the bandwidth of EQ curves, and sets the amount of overshoot function for shelving sections.
Master I N button Applies the EQ function type selected as described above The I N button light will go out if another EQ type is selected, indicating that the EQ remains unchanged until the I N button is selected again. Overload I ndicator This (just above the EQ Type window) displays any signal overload (red) at the output of the EQ and Filter sections. This can be disabled via the Sonnox button menu (see below). When active, the default mode for this function is latching, requiring a click to reset.
Use Dr ag Handles – Enables or disables the use of the EQ curve drag handles on the graphic display. Fill in EQ Bands – A colour infill can be used to shade the areas beneath the curve in the response display, to aid visibility of an individual section’ s contributions. Auto Scale Gr aph – The graphic display can be re-sized using the ‘ +’ and ‘ -’ buttons. Alternatively, the graph can auto-scale, depending on the amount of EQ gain employed.
4. Pr eset M anager Toolbar The Oxford EQ plug-in comes equipped with its own onboard Preset Manager, which is displayed as a toolbar at the top of the plug-in window, just as if the host created it (see above). The reasoning behind this is to allow increased portability of your presets across all the host applications, while also providing a consistent and versatile interface.
5. Specifications 5.1 Oxford EQ Specifications and Control Ranges Section Gain Frequency LF Filter LF Peak/Shelf LMF MF HMF HF Peak/Shelf HF Filter 6dB/Oct steps +/-20dB +/-20dB +/-20dB +/-20dB +/-20dB 6dB/Oct steps 20Hz - 500Hz 20Hz - 400Hz 30Hz - 600Hz 100Hz - 6KHz 900Hz - 18KHz 2KHz - 20Khz 1KHz - 20KHz Total dynamic range Harmonic Distortion Control induced noise Q/Slope > 138dB* (RMS unweighted) Undetectable < -95dBr (peak) 0 –36dB/Oct 0.5 – 16 0.5 – 16 0.5 – 16 0.5 – 16 0.
5.3 Plug-in I nstantiation Count for TDM and AAX-DSP The tables below show the number of plug-in instantiations possible in a single chip at three sample rates for each platform.
6. Copyr ight and Acknowledgements Trademarks and content copyright © 2007-Present Sonnox Ltd. All rights reserved. This Product is manufactured and supplied by Sonnox Ltd. under licence from Sony UK Ltd. The following patents protect this Product: GB2330747, GB2350505, GB2350956, US6581080 DIGIDESIGN, AVID, and PRO TOOLS are trademarks or registered trademarks of Digidesign and / or Avid Technology, Inc. VST is a Trademark of Steinberg AG.
Platfor m Specific Supplement S1. Supported Platforms Avid Pro Tools (LE, RTAS, M-Powered, Pro Tools HD) and Pro Tools 10 (HDX & Native) VST Native Audio Units Native S2. System Requirements These requirements are current at this revision of manual. For latest system requirements, please see the website www.sonnox.com Pro Tools Pro Tools 7, 8, 9 & 10 Approved Pro Tools CPU, OS and hardware configuration (see www.avid.com) Mac OSX 10.
