User’s Manual
VXP M I C R O P H O N E S M A R T P R E - A M P L I F I E R C O M P R E S S O R D E – E S S E R E X P A N D E R S E M I – P A R A M E T R I C E Q U A L I Z E R USER’S MANUAL Version 1.0 1999, PreSonus Audio Electronics, Incorporated. All rights reserved.
W A R R A N T Y PreSonus Limited Warranty PreSonus Audio Electronics Inc. warrants this product to be free of defects in material and workmanship for a period of one year from the date of original retail purchase. This warranty is enforceable only by the original retail purchaser. To be protected by this warranty, the purchaser must complete and return the enclosed warranty card within 14 days of purchase.
1999, PreSonus Audio Electronics, Incorporated. All rights reserved.
TABLE OF CONTENTS 1 Overview 1.1 Introduction 1.2 Features 2 4 5 Controls & Connections 2.1 Front Panel Basic Layout 2.2 Mic Preamp Section 2.3 Smart Compressor 2.4 Expander 2.5 De – Esser 2.6 Equalizer 2.7 Master Section 2.8 Back Panel Wire Diagrams 2.9 Power Supply 3 10 14 15 16 17 17 19 20 20 Operation 3.1 Dynamic Microphones 3.2 Phantom Powered Microphones 3.3 Insertion Points 3.4 Using Return as Line-In 3.5 96k/24-Bit Digital Output Card 4 22 22 22 22 22 Technical 4.
1 OVERVIEW 1 . 1 I N T R O D U C T I O N Thank you for purchasing the PreSonus VXP Voice Processor with Microphone Preamplifier – De-Esser – Expander – 4 Band SemiParametric Equalizer. The VXP by PreSonus is the only voice processor on the market that features a transformer coupled, Class A Mic Pre, Preset Compressor, De-esser, Expander, 4 band semi-parametric EQ, Peak Limiter and an optional 96k/24 Bit digital output card.
OVERVIEW 1 . 2 F E A T U R E S The following information is a summary of your VXP’s features: v Microphone Pre-Amplifier. Your VXP contains a Class A discrete input buffer followed by a dual servo gain stage. This arrangement results in ultra low noise and wide gain control allowing the VXP user to boost desirable signal without increasing unwanted background noise (NO capacitors!). Ø 48 Volt Phantom Power. The VXP has 48V Phantom power available.
OVERVIEW Ø IDSS Control. The VXP offers a very high quality transformer and features an IDSS control (this control adjusts the drain current on the input FET amplifier altering the even harmonic levels of the signal being passed) with an adjustment range of 0% to 100%. The 0% position passes a pure signal. As the control is rotated to the 100% position, the signal’s even harmonic series is boosted giving the signal “warmth” very much like a vacuum tube or similar to the sound of analog tape saturation.
OVERVIEW control with the outer ring for threshold set and the inner knob for ratio adjustments. This feature gives you the benefit of seamless noise reduction through downward expansion ridding the signal of unwanted background noise. A 4 segment LED meter monitors the degree of expansion. v De - Esser. A variable De-Esser with a range of 800Hz to 8kHz removes unwanted sibilance (hiss or “S” sounds) while allowing the signal to remain completely natural.
OVERVIEW Ø 80Hz. An 80Hz filter is provided for eliminating low frequency noise. This lets you greatly reduce background noise such as air conditioners or wind noise with the flick of a switch without effecting the desired frequencies. Ø In /Out Switch. An In /Out switch is provided to audition the signal in an equalized version as compared to a direct unaffected signal. Ø High Mid-Range.
OVERVIEW Ø Level. The output of the VXP is adjusted by the Level control and is useful for compensating for gain loss due to compression or to decrease output signal that boosting frequencies with the Equalizer section may have caused. The output is variable from –70 dB to +10 dB. Power. A BIG RED lighted push-button power switch is located on the front of the VXP for your convenience.
2 CONTROLS & CONNECTIONS 2 . 1 F R O N T P A N E L B A S I C L A Y O U T Notice that the front panel of the VXP is divided into six sections - section one is the Mic Preamp.
CONTROLS & CONNECTIONS Compressor Section contains: • Pre-Set Selector • Level Control • Process In/Out Switch • Gain Reduction Meter 11
CONTROLS & CONNECTIONS Expander Section: • Threshold Control (Outer Ring) • Ratio Control(Inner Knob) • LED Expansion Meter De-Esser Section: • Threshold (Outer Ring) 12
CONTROLS & CONNECTIONS • Frequency (Inner Knob) • Gain Reduction Meter 13
CONTROLS & CONNECTIONS EQ section: • 4 Band Semi-Parametric • Low Shelving Control • Low Mid Q Select Switch • Low Mid Level (Outer Ring) • Low Mid Frequency Select (Inner Knob) • 80 Hz Filter Switch • EQ In/Out Switch • High Mid-Range Level Control(Outer Ring) • High Mid-Range Frequency Control (Inner Knob) • High Mid Q Switch • High Shelving Control 14
CONTROLS & CONNECTIONS Master Section Includes: • Peak Limiter Control • Level Control • Limiter LED Meter 2 . 2 M I C P R E A M P S E C T I O N GAIN: This control provides 60dB of gain. IDSS CONTROL: Selects the amount of increase (0% to 100%) applied to the even harmonic series of the signal being amplified by the VXP. The effect of manipulating the harmonic distortion is of increasing or decreasing the apparent “warmth” of the signal.
CONTROLS & CONNECTIONS Phantom power through the XLR input. This power is supplied at a constant level to prevent any degradation of audio quality. PIN 1 GND PIN 2 +48v PIN 3 +48v XLR connector wiring for Phantom Power PAD: Engaging the Pad switch provides -20 decibels of attenuation with the push of a button. This is a very useful feature for rapidly reducing the level coming into the VXP and thus preventing the input signal from overdriving (distorting) the input.
CONTROLS & CONNECTIONS verse section with much louder portions of signal typically found in the chorus sections of a song. The lower ratio settings give greater range within the performance. These settings are useful for dramatic readings and any type of spoken word performance. MEDIUM: Five factory presets with Ratios ranging from 1.6:1 up to 2:1 are found in these settings. Using these presets would be effective when more control over transients is necessary.
CONTROLS & CONNECTIONS An Expander is a processing device used to increase the dynamic range of the signal being processed through it or in the case of down ward expansion, as in the VXP, to decrease the signal. Expanders can make quiet sounds quieter and loud sounds louder. Downward expansion provides a hybrid result, i.e., signals above the Threshold are untouched while those below the Threshold are attenuated at a ratio set by the Ratio control.
CONTROLS & CONNECTIONS 19
CONTROLS & CONNECTIONS 2 . 6 E Q U A L I Z E R The Equalizer section of the VXP contains a 4 Band Semi-Parametric Equalizer. There is also available Low Mid Narrow Q Select and High Mid Narrow Q Select, as well as, an 80Hz filter. An In/Out switch is provided for auditioning the effects that the equalizer settings are having on the signal being processed. LOW SHELVING The 100Hz control adjusts frequencies 100Hz and below.
CONTROLS & CONNECTIONS the effect from the center frequency is 1/4 as wide. The HI Q OUT position is a much broader in its effect and the tonal variation derived is similar to a control you may have used on a hi-fi or guitar amplifier. When the HI Q switch is engaged, the effect on the frequency is much more specific. The selected frequency is reduced or increased in greater proportion than the nearest frequencies.
CONTROLS & CONNECTIONS footsteps or other types of vibrations from being transmitted through the microphone stand into the microphone. 2 . 7 M A S T E R PEAK LIMIT This control adjusts the operating parameters of the Peak limiter. This device is variable allowing the user to select a point from 0 dBu to +24 dBu. The set point is the point that a signal being processed will not be allowed to go above.
CONTROLS & CONNECTIONS The Return / Line In connector of the VXP is provided for use in conjunction with audio process devices such as reverbs/delays and as a Line In for recording media such as tape machines, hard disc recorders, or DAT’s. TIP High (+) RING Low (-) SLEEVE GND Cable Wiring Diagram for Balanced Send / Return Jacks The Send Jack on the back panel of the VXP routes the signal being processed by the unit to an outboard device such as a reverb or delay or to recording media. 2 .
3 OPERATION 3 . 1 D Y N A M I C M I C R O P H O N E S Dynamic microphones are characterized by lower output levels. Hence, more gain is needed to amplify a dynamic microphone to operating level. Occasionally it is necessary to add the –20dB pad to the microphone to avoid distortion (e.g. when recording percussion). Do not use phantom power when using dynamic microphones. 3 .
OPERATION PreSonus VXP. It has AES/EBU and SPDIF output connectors, as well as, an auxiliary ¼” TRS analog Line input connector. The card has a selectable sample rate of 96kHz, 48kHz and 44.1kHz. The A to D converters are made by Crystal Semiconductor for superior performance. Psycho-acoustic dithering is provided to improve BIT resolution characteristics which may become noisy when conversion from 24 BIT to 16 BIT sampling is necessary.
4 TECHNICAL VXP Channels ............................................................................................ONE Dynamic Range.............................................................................. >115dB Noise Floor............................................................ @ +12dB Gain -97.2dBu Headroom ...................................................................................... +24dBu Frequency Response.............................................................
TECHNICAL Expander Threshold Range..............................................................-70dBu to +20dBu Ratio Range ................................................................................1:1 to 20:1 Metering (4-LED)................................................................ Gain Reduction De- Esser Threshold Range..............................................................-40dBu to +20dBu Frequency Range..................................................................
TECHNICAL Output Connectors............... XLR Balanced 1/4” TRS Balanced/Unbalanced Output Impedance ......................................................................... 51Ohms Metering (8-LED)........................................................................ Full Scale Output Headroom ........................................................................... +24dBu Physical Power Supply ............................................ Internally Regulated Linear Type Power Requirements.........
