Manual Model 9738 Dual Channel Parametric Tube/LC Equalizer Qure Manual Model 9738 By Hermann Gier and Paul White Version 2.2 - 1/1999 The information in this document has been carefully verified and is assumed to be correct. However Sound Performance Lab (SPL) reserves the right to modify the product described in this manual at any time. Changes without notice. This document is the property of SPL and may not be copied or reproduced in any manner, in part or full without the authorisation of SPL. Limitations of Liability: In no event will SPL be liable for any damages, including loss of data, lost profits, cost of cover or other special, incidental, consequential or indirect damages arising from the use of the unit, however caused and on any theory of liability. This limitation will apply even if SPL or an authorised dealer has been advised of the possibility of such damage. SPL electronics GmbH P.O. Box 12 27 D- 41368 Niederkruechten, Germany Phone +49 - 21 63 / 98 34-0 Fax +49 - 21 63 / 98 34-20 eMail: info@ soundperformancelab.com © 1999 SPL electronics GmbH. All rights reserved. QURE® is a registered trademark of SPL electronics GmbH. Foreword............................................................................................... Thanks.................................................................................................... Introduction......................................................................................... Operation Safety................................................................................. Connections.......................................................................................... Applications......................................................................................... 3 3 4 7 8 9 Contents CONTROL ELEMENTS WARM UP & READY .......................................................................... 10 MASTER ............................................................................................... 10 IN ........................................................................................................... 11 HF/LF CUT ON .................................................................................... 11 HF CUT .................................................................................................. 11 LF CUT .................................................................................................. 11 LF ........................................................................................................... 12 MF .......................................................................................................... 12 HF ........................................................................................................... 13 BW.......................................................................................................... 13 B/C ......................................................................................................... 15 LF/MF/HF ON ..................................................................................... 17 QURE ON ............................................................................................. 17 QURE ..................................................................................................... 18 SHIFT QURE ......................................................................................... 20 OUT........................................................................................................ 20 Power supply........................................................................................ 21 Specifications....................................................................................... 22 Warranty................................................................................................ 23 Dear customer, Thank you for the confidence you have shown towards SPL electronics GmbH by purchasing the SPL QURE.You have decided to use a tool of high performance which sets you in the position to have faster success and a better sound quality in your music productions and pre-masterings. As a typical SPL unit the QURE combines exemplary specifications and high manufacturing standard with excellent sound quality to provide you a precious component for recording purposes. Please read this manual carefully to ensure you have all the information you need to use the QURE. We wish you every success with it. Your Sound Performance Lab-Team Foreword I would like to start with my thanks to all our staff, who created what is to be described here. The importance of their exceptional qualification and talents cannot be overestimated. Special thanks to Wolfgang Neumann for his exceptional creativity in EQ and filter design. Our products are often tested and compared in many publications and by our customers themselfs and constantly valued with best results. I would like to pass on this broad appreciation to those, who deserve it ­ my excellent colleagues. Hermann Gier Thanks 3 Introduction The QURE is a parametric equalizer for creative sound design Congratulations on purchasing the QURE, one of the most advanced and musical sounding parametric equalizer currently available. The QURE is a fully parametric equalizer, specially designed to meet the most demanding studio applications. It is designed as 3band, two-channel system with input and output gain controls, high-cut and low-cut filters as well as the new QURE-circuitry for the creative and corrective sound shaping of vocals, instruments and complex stereo material. Both balanced XLR and balanced stereo jacks are provided for signal connections to and from the QURE. Its musically optimized parametric filters, based on a sophisticated refinement of state-variable-filter technology (SVF), include proportional bandwidth, tube technology for a warm and fat sounding mid-range, LC filtering for clear and transparent upper frequencies, transistor and semi-conductor technology for a volumious low end. The proportional-Q principle provides precise control over a frequency range, from 15 Hz to 21 kHz, while the low noise level of -99 dB (A-weightened), and the enormous dynamic range of 113 dB, make the QURE ideally suited for mastering and cutting. By employing circuitry designed around the principles of perceived sound, rather than simply designing by numbers, the QURE overcomes the limitations of conventional parametric equalizers. The QURE combines a technology-mix of five decades of audio engineering Exemplary specification contribute to the excellency of this EQ The QURE circuitry The QURE circuitry improves presence, clarity and depth. It can also be used to cure recordings from digital harshness. The QURE circuitry is a new SPL development which gives the name for the unit and also represents a new technology, which uses coils to increase the presence of vocals and the depth of the music. At the same time it is ideally suited to cure recordings from digital harshness. The name is derived from `cure' in combination with Q from EQ. The signal runs through a tube circuitry featuring a Sovtek 12 AX 7 double triode tube in a mixed current/voltage coupling mode. This stage is extremely clip-resistant and produces a pleasant and musical sounding tube-THD spectrum. A new LCR network combined with a 12AX7 tube reacts on the dynamic response of the audio and alters THD and phase response. The QURE ON switch puts a coil/condenser/resistor filternetwork (LCR) into the tube output stage. This network is integrated into the coupling path of the tube and reacts on the dynamic reponse of the input signal by influencing THD spectra and phase response. The QURE potentiometer changes the frequency response and produces a fresh and silky top-end and a mid-range free of sharpness and harshness. The presence and `aura' of vocals is largely improved. 4 Proportional Q Unlike most other equalizers which use constant-Q filters, the QURE adopts the proportional-Q principle to realize maximum musicality. Conventional constant-Q designs keep the amplitude constant, regardless of the adjusted bandwidth (Q).The disadvantage of this is, when it comes to sound creation, frequencies above and below the center frequency are often boosted so intensely that they lose their musicality. With proportional-Q it is quite different; the amplitude of the processed frequency band is reduced as the bandwidth broadens. Adjusting the bandwidth back to a narrow bandwidth (high Q), will increase the amplitude of the center frequency to its former level. Furthermore, with proportional-Q, there is no need to constantly readjust the boost/cut control when varying the bandwidth ­ as is usually necessary with constant-Q equalizers. It is generally perceived that equalizers based upon constant-Q designs produce acoustically comparable results, and suffer from limitations in the areas of sound flexibility and musicality. Often there is only one truly usable position on the Q-control. The proportional-Q principle offers a wide range of possible potentiometer settings and makes it easier to identify the desired frequencies within the sound spectrum ­ even subtle nuances become clearly audible. Equalizing with proportional-Q is therefore more intuitive and subjectively musical than with constant-Q equalizers. The QURE forms its response curve around the center frequency with a bell-like response, so that frequencies closer to the center frequency are emphasized slightly more; frequencies further from the center are less affected. The development of these filter curves was the result of extensive listening tests, and the result is an equalizer that combines technical excellence and precision with unsurpassed musicality. With the musical proportional-Q principle the amplitude of the processed frequency band is reduced as the bandwidth broadens. Equalizing with proportional-Q is more intuitive and subjectively musical than with constant-Q equalizers. The Frequency Bands The QURE is configured as a two-channel, 3-band equalizer with a separate hard-bypass switch for each band. The filters are connected in series. The three filters bands cover a frequency range from 15 Hz to 21kHz. In addition each channel is equipped with high- and low-cut filters. Tuning the equalizer is very intuitive because the frequency control law has been designed to match the characteristics of the human hearing system.The perfectly linear phase response of the QURE circuitry, combined with its wide bandwidth, contributes to the sonic excellence of this esoteric equalizer. The mid-band features the `non-reciprocal response' of the BOOST/CUT control which qualifies this band to operate as a notch filter, too. Cutting is allowed to -36 dB at high Q (Q 5) whereas the low and high band offer cutting of -15 dB. The sonic advantage of the `non-reciprocal response' design is the vast dynamic response making the filter sound very open and clear. The mid-band features a `non-reciprocal response' of the BOOST/CUT control The QURE is a two-channel, 3-band equalizer with the filter bands connected in series 5 General Features Stepped potentiometers for easy recall; individual bypass for each filter band To allow easy recall of all control settings the QURE is equipped with stepped potentiometers throughout. The number of steps is optimized to the control function: 11 steps for bandwidth, 31 steps for frequency and boost/cut, and 41 steps for input gain, HF/LF Cut filters, and QURE control. Each band can individually be switched in and out of the signal path making comparison easy and avoiding the need to nullify the boost/cut control. Each filter is mounted on a separate printboard featuring a `central grounded shield layout' (CGSL) for maximum rejection of interfering frequencies. Single op-amps are used throughout to minimize noise and THD. The tubes in use are the well-acclaimed Sovtek 12 AX 7. Furthermore selected custom made condensers are used to produce harmonical and pleasant sounding THD spectra. The frequency controls are also custom made featuring a control characteristic that is designed to realize a gentle frequency sweep with a musically optimized control range. Central grounded shield layout, single op-amps, Sovtek tubes, custom made condensers and potentiometers Overview · 2x 3-band EQ with variable HF and LF cut filters · QURE circuitry (Tube + LCR) · Variable input gain (-12 dB to + 18 dB) · Variable output gain (-7 dB to + 4 dB) · Hard-bypass for each filter band and both cut filters · Master relay hard-bypass for entire unit · Central Grounded Shield Layout · SPL super-balancing hybrids (CCMR -90 dB) · Tube warm up circuitry for prolonged tube-life · Overrated internal toroidal power supply · PREMIUM-Version (recommended): LUNDAHL in- & output transformers (LL1539 & LL1540) 6 The housing of the QURE has the standard 19"-EIA format and occupies 2U (88.9 mm) in y ...