Remote Microphone Preamps

Jul 1, 2004 12:00 PM, By Strother Bullins

Convenience, Control and Better Sounds

Among the multitude of cringe-worthy phrases heard by those working in pro audio is the venerable war-horse, “Make it sound good.” We've all heard someone mutter those words — or its sister cliché, “Make us sound good” — at one point or another. The worst part about hearing these phrases is that they don't really make sense.

More often than not, the engineer's job isn't to “make” something; it's to capture a sound that already exists. And for that, the cleanest signal path between a transducer and the final source is required. Unfortunately, the ultralong pathways of a tiny mic-level signal — often with a foray between multiple inputs and splitters — can drastically alter phase, frequency or transient response before the signal even touches a preamp.

The easy answer to this predicament is to place the preamps as close to the mics as possible. However, by using standard mic preamps, this simple act of preserving signal purity can create a logistical nightmare, especially during a live show, broadcast or recording where the band kicks in 10 dB louder than the gain trims that were so carefully set during soundcheck and you're having to mix 300 feet back at the house position or in a remote truck.

Thankfully, a number of manufacturers offer solutions to eliminate the need for long mic-level runs, and in the process have created easily manageable, high-quality mic preamps. From these remote-controllable preamps, to consoles featuring external stagebox-loaded mic pre's, to inventive snake systems impervious to interference, everything that an engineer could use to protect mic-level signal is readily available — and many of these products are detailed on the next few pages. These devices may not magically make every client sound good, but they can help create an environment for superior sonic integrity, and isn't that really what an engineer's job is all about?

AMS Neve's (www.ams-neve.com) 88R Remote Microphone Rack offers the best in old and new mic preamp technology by combining classic Neve Air Monserrat or 1081 mic amps with remote control via PC or an AMS Neve Encore automation computer. AMS Neve reports that Macintosh control software will be available in the near future. The Air Monserrat preamp is a late-'70s — era mic amp suited for ambient miking, while the 1081's early-'70s design responds best with close-miking setups. Any combination of the mic preamp modules can be utilized in the 12-slot, four-rackspace 1081R Intelligent Housing, which connects via a rear panel Varicon connector. Control is achieved by connecting the rack to the chosen computer via 9-pin serial control cable and then to an RS-232-to-RS-485 converter. The output of the system is a 56-pin Elco/EDAC connector, carrying up to 12 circuits, typically terminating in XLR or TT plugs. Operational settings such as gain, phase and a 20dB pad can be easily controlled from the rack or the system's interface screen. A full 88R Remote Microphone Rack with software is available for $10,000. Purchased separately, the 1081R rack is priced at $3,200, 1081R Remote Software is $500 and mono Air Monserrat and 1081 Mic Preamps are $1,400 each.

The 8-channel Model 1788 Microphone Preamp ($4,995) and Model 1788RC Remote Controller ($1,499) from Aphex (www.aphex.com) create a capable preamplification system with both analog and optional digital outputs. Besides eradicating noise problems associated with long cable runs, the 1788 eliminates the need for splitter boxes by providing five outputs — two analog and three digital — that are simultaneously usable. The flexible system is controllable via the Model 1788RC, a PC running Aphex's 1788SW controller software or through any device generating MIDI, such as a MIDI controller, console, sequencer or show control system. The two-rackspace Model 1788 offers balanced Jensen transformer-coupled mic preamps and includes a unique microphone output limiter, 26dB pad, adjustable maximum output level, a 700Hz test-tone generator, comprehensive LEDs and a front panel headphone output. The unit's optional digital output module features 24-bit AES/EBU, TDIF and ADAT optical capability. The Model 1788RC's MIDI-protocol remote control offers adjustment of all parameters, setups, snapshots and preset recalls, and up to 16 units — 128 channels — can can be controlled with only one control line.

Respected English manufacturer Crookwood (www.crookwood.com) recently re-engineered the preamp stage of the Paintpot ($2,400) and iPre ($5,500 with controller) remote-controlled mic amps and, to the joy of Crookwood fans everywhere, subsequently reduced list prices. Confidently claiming a main design criteria of “sonic neutrality,” Crookwood uses fully balanced amplifiers — one complete preamp per phase — and high-current outputs. According to Crookwood, its attention to detail and quality has given the company a reputation of offering very high audio quality and great remote-control capability to boot. Crookwood's mic preamp remote control is available via a user's DAW software or by a wired assignable unit communicating through a single pair — for instance, by a mic tie-line — from the controller to the preamps. MIDI and HTML control options are currently in development and will be available later in 2004. The Paintpot is a portable 2-channel preamp that closely resembles a gallon-sized paint can, hence the moniker. The iPre comes in modular configurations: two channels at a time and up to eight channels are available into a single-rackspace box. A separate control rack houses the iPre's external power supply and control processor, and can power up to 4-channel racks, which gives 32 channels of preamp in five rackspaces. Paintpot and iPre channels each offer a dedicated mic, line, -10dB unbalanced line and DI input, along with optional 24-bit, 192kHz A/D converters for digital output.

DiGiCo's (www.digiconsoles.com) D5 Live 56, a 64-channel worksurface, provides remote mic pre control through its stage-side DiGiRack, each containing 56 mic preamps and A/D converters, eight D/A converters and is connected to the console via optical fiber. All console settings stored on the D5 can be easily edited on a PC — or transferred to another D5 — by simply plugging a miniature USB key on the front of the desk. Nearly 500 feet of fiber cable is provided with the stage-side DiGiRack, reducing the length of cable between a mic and the D5 to around 10 feet. For users needing more inputs, a second side-stage DiGiRack can be easily added. Yet another DiGiRack — located at the D5 — contains another 56 external I/Os for inserts, effects sends, local monitoring and playback. A customizable setup of DiGiRack input and output cards is available.

The popular PRE ($2,495) from Digidesign (www.digidesign.com) is a remote-controllable, 8-channel mic preamp featuring discrete, matched transistor hybrid preamp circuits. Designed to perfectly complement the 192kHz-capable Pro Tools|HD recording environment, the PRE accepts a variety of input signals — mic, line and DI — on all eight channels. Per channel, the PRE offers 48-volt phantom power, a highpass filter, phase invert, balanced inserts and an -18dB pad. A total of nine pre's can be chained together, offering 72 channels of preamplification. The PRE's remote capabilities are controlled via Pro Tools software or any Digidesign control surface, which is particularly intriguing considering the company's recently announced foray into the sound reinforcement market. With reports of a live console system shipping before the end of this year, the flexible PRE looks more appealing for event use than ever before.

FiberPlex (www.fiberplex.com), a leading manufacturer of optic data communications equipment for the U.S. government, recently introduced the Light Viper VIS-1832 fiber-optic system, featuring a 32×8 audio input stage box and a single-rackspace unit placed at the console position. Connecting these two components is a mil-spec fiber-optic cable weighing less than two pounds per 100 feet of cable run. The Light Viper's stage box accepts inputs of balanced or unbalanced XLR or TRS mic/line-level audio, phantom power is provided to all mic inputs and 24-bit/96kHz A/D converters are standard. Optional optical outputs on the stage box allow for a separate stage monitor feed and a third for sending audio data signal to another destination, such as a remote broadcast or recording truck.

The Focusrite (www.focusrite.com) Liquid Channel was designed to address the needs of engineers who couldn't — or didn't want to — transport large amounts of analog mic preamps and compressors from gig to gig. With increasingly complex patching arrangements in modern mixing setups, acquiring sounds via classic gear in a digitally dominated environment can be somewhat of a logistical nightmare. As a result, Focusrite decided to create a solution that precisely replicates the sonic performance of many of these coveted analog devices in a reliable, ultimately flexible, all-in-one package. Besides encompassing a head-spinning collection of classic sounds created through sonic-modeling techniques called Dynamic Convolution, the $3,495 Liquid Channel also offers a vast analog front end configurable for any input stage. The unit comes with 40 mic preamps and 40 compressor replicas; Focusrite promises more models for the future, citing the Liquid Channel's “infinite expansion capabilities.” A digital EQ — based on Focusrite's classic equalizers — is also included. Front panel controls are all digital, allowing settings to be saved in one of 100 memories. Complete system remote control, data management and archiving are provided via the rear panel USB port where users can connect to LiquidControl, Liquid Channel's software application. Offered free of charge, LiquidControl also allows the downloading of additional replicas not present in the factory presets.

Grace Design Model 801R

Grace Design (www.gracedesign.com) has always been known for its visually striking, high-quality pro audio products, and the Model 801R ($4,995) bolsters that well-deserved reputation. The 8-channel Model 801R uses the same preamplifier circuitry as the company's proven 801 mic preamp, but is remote controllable by a simple software platform controlling the analog circuit. The optional 801R RCU ($995) allows eight Model 801Rs — 64 channels — to be controlled from up to 1,000 feet away. Grace's proprietary LNLD (Low-Noise, Low-Distortion) digital gain control cell was developed to give the Model 801R seamless digital control of the analog circuitry while maintaining the performance users have come to expect from the standard Model 801. The 801R features a large backlit LED to provide level, 48V phantom power, mute and all other preamplifier status information, all of which can be stored in user presets for scene memory and recall. Channels can be grouped for concurrent level adjustment.

The Modular Mic Preamplification System from Harrison (www.glw.com) is a three-rackspace chassis outfitted with a total of up to eight channels per unit; the modular configuration can be ordered with less preamps if desired. Each preamp features two inputs per channel, XLR I/O, 48V phantom power, -20dB pad, phase reverse, ground lift, a four-segment input meter and lighted switches. The system's electronically balanced preamps have a maximum gain of 70 dB. The Modular Mic Preamplification System is a part of Harrison's Stand-Alone Series, which comprises a variety of rackmount, flexibly configured products including digital routers, converters, DTC Digital Tools and the SuperMon 5.1 Surround Monitoring System. The Modular Mic Preamplification System's price varies depending on the amount of installed preamps.

Designed to replace multicore snakes with a simple pair of coaxial cables, the InnovaSon (www.innovason.com) Stage Box is an audio rack and transmission system featuring installed mic preamps, XLR connectors, 48V phantom power, phase reverse and converters in a self-contained rack. All Stage Box parameters are remote-controlled from the mixer and audio arrives through the aforementioned coaxial cables. The Stage Box also functions as a digital splitter, feeding two or three InnovaSon Sensory consoles. Only a small run of cable is analog, and all signals quickly come into the digital domain. Standard with the InnovaSon Grand Live and available as an option with other InnovaSon desks, the Stage Box is upgradable with space for adding extra input or output modules.

DALLIS — the Digital And Live Level Interface System — from console manufacturer Lawo (www.lawo.de) is a versatile I/O product designed for use with Lawo matrices and mixing desks. Featuring fiber-optic connections, DALLIS' modular concept is based on mounting frames, which can be equipped with a wide choice of different I/O designed as plug-in cards. Each DALLIS frame is controlled by a Master Card, which connects via MADI as a contribution port and performs the transfer of control data. Building on DALLIS technology is Lawo's Nova17, a digital audio matrix that routes up to 128 mono inputs and outputs along with a MADI interface supplying an extra 56 channels. When outfitted with Lawo's analog mic/line interfacing boards, the system serves as a well-performing Ethernet or serial interface-controlled preamplification system.

Peavey MediaMatrix X-Frame (top) and MM-8802 audio breakout box

Peavey (http://mediamatrix.peavey.com) boasts that its MediaMatrix division offers systems designed to replace outdated “conventional wisdom” systems. Racks of outboard processors, equalizers, crossovers, routers and mixers are replaced by a PC-based cardframe, loaded with Peavey's MM-DSP Series of audio processing cards and software, and are controllable from any location. In its smallest form, MediaMatrix exists as a rackmount audio processor; at a much larger size, it can be a complex router, processor and distributor for many audio transports, including audio via Ethernet networks. The MediaMatrix X-Frame 88 and MM-8802 audio breakout box is of special interest to those looking to use remote-control preamplification. The X-Frame 88 is a single-rackspace, 8-input/8-output digital audio processing system that is expandable to 24×24 I/O with the addition of two MM-8802s. Features include digital control of all I/O levels, remote control via RS-485, 24-bit quantization and 32, 44.1 and 48kHz software-selectable sample rates.

When Solid State Logic (www.solid-state-logic.com) introduced the XLogic series of outboard signal processing units, SSL-loving engineers throughout the pro audio industry seemed to simultaneously mutter, “It's about time.” Appealing to SSL fans that seek remote preamp control is the XLogic Four-Channel Mic Amp ($4,345) and XLogic SL944 Remote Control ($1,495). Much like the pre-existing SuperPre — SSL's 24-channel remote mic preamp controlled by an XL 9000 console — the one-rackspace XLogic 4-channel mic amp includes nearly all SuperPre features but repackages them for those who don't need all 24 of the SuperPre's channels. The SL944 Remote Control can control two XLogic Four-Channel Mic Amps via eight individual control sets with motorized gain and front panel phase reverse, hi-Z and a -20dB pad. The XLogic Four Channel Mic Amp offers front panel XLR inputs and rear XLR outputs, LED-assisted adjustment for phase reverse, hi-Z, -20dB pad and 48V phantom power. Gain is adjustable on the unit's front panel or remotely, and each channel offers a numerical display for channel number information. The included headphone connection can be used for any selected mic input, even for other preamps connected in a multi-unit setup. Finally, a D-connector frees the XLR outputs for other user needs.

The StageTec (www.stagetec.com) Nexus is a 100-percent digital routing system composed of multiple base devices that are part of a modular structure and are interconnected by fiber-optic cables. Operation of the Nexus is performed using control software that runs on a PC, and it is most often used as an I/O signal matrix for a Cantus mixing console system. Utilized in StageTec's Nexus are TrueMatch converter systems, which are designed for optimum A/D conversion by getting excellent total harmonic distortion and noise values for both high- and low-level signal values. This is achieved by using multiple preamps for various amplification ranges, each featuring its own A/D converter. When a signal is applied, a processor selects the most appropriate of the several converters on the basis of signal level.

Studer's (www.studer.ch) D19m component system was created to give engineers a flexible, digital modular recording system based on Studer's highest-quality conversion technology. Individual D19m units were designed to fit within a traditional 19-inch rack, occupying one or two units of vertical space each; a 1U card is four inches wide. Input cards feed a TDM Bus, while the TDM Bus feeds the output cards. Each card has a built-in power supply with optional redundant power supply and can be combined with any other D19m card to create a custom system. Along with many D19m I/O and converter cards, the D19m MP4RC Quad Remote-Controlled Mic/Line Input and serial interface-controlled D19m RCC Remote Controller cards give system users the freedom to operate the Studer mic preamps from a D19m GUI via and optical link. The MP4RC features four transformer-balanced mic/line inputs with gain control in 1dB steps. Each channel also features 48V phantom power, highpass filter, external mute, an additional split output, balanced outs and clip protection for all four channels.

The Summit (www.summitaudio.com) MPE-200, the first product introduced for the Element 78 line of solid-state processors, comprises two mic preamp channels with 4-band parametric EQ designed by Mr. Rupert Neve. Designed to be a user-friendly unit with a fully digital front end, the two-rackspace MPE-200 offers 25 onboard presets and full MIDI support. Other features include a dual-range highpass/lowpass filter, coarse and fine gain control for each section, floating and balanced output transformers and an analog-esque control panel with easy-to-read displays. The MPE-200 and its slave version — the MPE-200S — are remote-controllable via Pro Tools thanks to the new Extension 78 TDM plug-in. While both are fully remote-control-capable, the MPE-200S is specially designated for remote use. The slave unit has no front panel controls, which just so happens to create another added benefit for potential buyers: a lower ($4,400) list price than the $5,000 MPE-200.

Calling remote-control preamps “a need, no longer a luxury,” manufacturer Sytek (www.sytek-audio-systems.com) offers the MPX-4D ($2,860), a digitally controlled, 4-channel mic preamp. The unit offers control from either its front panel or from a PC interface. The MPX-4D uses Class-A, hybrid input stage preamplifiers based on hand-selected transistors. Each channel offers a high-quality gain control, three pushbutton controls for mute, phase and 48V phantom power functions, and a peak indicator set at -8 dB before clipping the signal output. Also included is a high-resolution optical encoder for changing gain, which is displayed on a quarter-inch dot-matrix LED screen. Sytek also offers a special operational amplifier configuration of the MPX-4D featuring Burr-Brown op amps in any or all channels. According to Sytek, the Burr-Brown's high-quality amps result in a warmer, “tube-like” response in contrast to the “clean, ultrafast” response of its standard amp. A commonly built MPX-4D configuration includes Burr-Brown op amps in channels 3 and 4 of the unit.

Whirlwind's (www.whirlwindusa.com) E Snake system comprises E Snake Frames (ESF) and the E Snake Control system-management software. Two or more ESF frames are connected to each other through a 100MB Ethernet switch with either Cat-5 or fiber optics that are designed to replace traditional analog multipair audio snakes. Each ESF includes a hardware frame and motherboard that can be configured with up to four input and four output cards available as mic/line or line-only. The cards offer eight channels of audio each, so each frame can simultaneously transmit and receive up to 32 channels of audio. Multiple frames can be used to increase total capacity. The comparatively lightweight E Snake — 300 feet of 58-channel multipair cable with connectors weighing 175 pounds — is easily controlled via E Snake Control, which provides manipulation of input features such as mic/line switching, 48V phantom power, pad, limiter, gain control, channel labeling and metering.

The AD8HR ($2,200), an 8-channel mic preamp and A/D converter from Yamaha (www.yamaha.com/proaudio), features head amplifier circuitry gleaned from the company's PM5000 analog mixing console. The unit supports sampling rates up to 96 kHz and easily integrates into digital console setups. Offering a user-friendly front panel, the single-rackspace AD8HR offers a Head Amp Remote-Control function where channel phantom power and highpass filter cut-off frequencies may be switched on and off via remote control. This “stage box” capability allows the mic preamp to be remotely adjusted in 1dB steps from digital consoles. Up to 255 AD8HR units can be daisy-chained together using a standard 9-pin RS422 and a digital connection via AES/EBU. The rear panel AD8HR connections include eight XLR inputs, BNC-type I/O connectors for word clock and two D-Sub 25-pin AES/EBU digital output terminals.


Strother Bullins is a North Carolina-based freelance writer specializing in the professional audio and entertainment industries.

BEYOND SPECS
Controlling the Controller

Searching for the perfect remote-control preamp system goes beyond poring over Websites and comparing spec sheets to find the lowest THD, the best EIN rating and the widest, flattest frequency response. A listening test wouldn’t hurt either, so you can evaluate the tone of the preamp and listen for artifacts such as zipper noise or glitches that can creep in when parameters (especially gain) are tweaked. The next step is to compare features, I/O configurations and so forth, but one factor that can’t be over-estimated is the remote interface. How the system’s GUI works with you, the user, is critical and, unfortunately, this is one aspect that’s difficult to quantify.

Matching the platform—proprietary hardware controller or computer software—to your working style and preference is vital. For example, if you’re mostly Mac-based, do you really want to invest in a PC just to set gain trims? Is the interface elegant or clunky, requiring you to navigate through dozens of screens or windows just to flip the phase on an under-snare mic? Speed is everything, especially in live production, where at the last minute, the bass player decides to switch to an active bass with ultrahot pickups. In cases like these, how long it takes to get in and make a change can make a huge difference.

So while shopping for a remote system solution, give it a listen and look at all of the facts before buying.—George Petersen

Click here to satisfy your gear lust with more mic pre pics.






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