Focusrite MH435 Platinum OctoPre 8 Channel Microphone PreampThe industry reference for signal processing.
The Platinum OctoPre is an 8-channel Focusrite Mic pre amp featuring 8 classic Focusrite mic pre's and 8 independent compressors/limiters. Its transistor-based Class A mic pres are the same as those featured elsewhere in the award winning Platinum line with the same Red/ISA full-bandwidth philosophy, ensuring detail and clarity without coloration. Class A is a type of amp design in which a standing DC current runs through the amplifier circuits all the time. The result of using Class A circuitry is linear (distortion free) audio performance.
The first two super channels also feature phase reverse, as well as TRS inputs on the front panel for quick and easy, DI-free instrument plug-in. Each channel features a discrete, revolutionary compressor/limiter circuit, providing a warm-sounding compressor, which morphs into a brick wall limiter to avoid those critical overs.
The OctoPre has 8 XLR mic inputs, 8 line level inputs and 8 line level outputs connected via two 25-pin d-sub connectors. This allows the OctoPre to be connected to a patch bay and have every input connected at all times for easy operation. These D-type connectors may be routed to 8 external XLRs by means of an 8-way 25-pin D-type to 8 XLR breakout cable available separately (wired to the TASCAM spec).
Features
- Eight Focusrite Class A Pre amps
- Eight independent Focusrite Compressors/Limiters
- Up to 16 digital outputs (24bit, 96kHz)
- Two Super Channels with TRS Jack inputs and phase reverse on the front fascia.
- No DI required
- 96 kHz ADAT Lightpipe, AES/EBU, and S/PDIF output options
- Word Clock synchronisation
When you take into account the exceptional dynamics of this unit, which more than equals many stand alone units, the price per channel comes down to more reasonable levels
Chris Martin, Music Mart Magazine, March 2003
On spec, this one looks like a knockout bruiser with a list of stats that will make competitors train a little harder. It's also got a pedigree - the Focusrite name alone makes this one worth getting a ringside seat.
Bill Stunt, Recording Magazine, May 2003
With eight pristine Focusrite channels, class A Focusrite processing, eight compressor/limiters and almost all the interface options known to man, OctoPre is the perfect partner for any Digital audio workstation, making high quality, multi-channel recording (eg. Drums and synths) easy.
Equally, it can be utilised as an instant location recording solution, (as part of an ultra-compact 8-channel system with a laptop,) or as an additional set of pre amps for any analogue or digital console or hard disk recorder.
Each channel boasts the award-winning Pre amp featured in VoiceMaster PRO, alongside a revolutionary dynamics circuit, ensuring transparency and warmth with total control. The first two
Super channels also feature phase reverse, as well as TRS Jack inputs on the front fascia for quick and easy, DI-free plug-in.
Finally, the high quality digital converter options cover almost every interfacing eventuality. Up to sixteen digital outputs can run simultaneously with any mix of analogue outputs, and all the settings are adjustable, directly from the front fascia.
With this entire package fitting into a single 1U chassis, OctoPre sets the standard for multi-channel recording solutions.
Class A Pre Amp
OctoPre boasts eight of the best; the award-winning industry standard VoiceMaster pre amp, now featured in the new VoiceMaster PRO. This pre-amp demonstrates the same wide-bandwidth philosophy featured in the original
Neve-designed Focusrite units from years past. Focusrite's custom pre-amp ensures low noise and distortion, delivering clarity and warmth without unwanted artefacts, displaying the signature sound for which Focusrite has become famous. Also found in this section are Phantom Power, a Line level switch and a High Pass filter, enabling OctoPre to handle a multitude of audio sources simultaneously, with style and grace.
Revolutionary Dynamics Control
OctoPre features eight independent compressor/limiters, whose revolutionary circuit design allows dynamics to be handled via a single control. Starting with a brick-wall limiter (to avoid critical overs), the rotary control then allows you to add increasing amounts of compression.
Two independent side-chain control circuits are used for each channel of dynamics, one for limiting and one for compression. The limiter and compressor side-chains each generate two separate control signals, one fast and one slow, that are then fed to the gain change elements in the audio path. The gain control elements consist of a pair of custom Optos, which follow a crossover network that splits the audio into two bands,
high and
low. The fast side-chain drives the high frequency opto, whilst the slow sidechain drives the low frequency opto. This process ensures less distortion when the limiter is reacting to very fast transients. By splitting the response, only the high frequency section of the waveform is drastically affected, reducing inter-modulation distortion, and therefore non-related harmonics, providing a far more musical effect.
In addition, both the side-chains operate as feedback systems. Thus, the amount of compression and limiting is calculated using the level after the split opto stage. The advantage of this feedback system is that the limiter senses the level after compression has been applied and therefore the limiter only works when it absolutely has to.
The dynamics control also introduces an additional make-up gain, balancing the level change caused by compression. This auto make-up gain ensures the output level to the A/D remains constant whilst further compression is applied. Consequently, any input levels already set will not require any further adjustment during dynamics set-up.
Only one dial, but all the control, providing the quickest route to a warm, controlled, yet entirely musical signal. All the excitement and all the control without compromise.
Super Channels
OctoPre's first two channels also feature high quality instrument inputs and phase reverse, both available direct from the front fascia, avoiding the need for a separate two channel DI box. Both channels allow all three sources to be patched simultaneously, with input selection switchable direct from the front fascia, allowing the unit to be permanently racked and patched to your own specifications.
Digital Interface options
Two high quality A/D converters are available for OctoPre. The converters are 24 bit and 128 x over-sampled, handling sample rates of up to 96kHz, but can dither down to 20 or 16 bit. All frequency settings and bit rates can be altered from the front fascia, with an ADC lock LED to show when word clock is synchronised.
Option 1: ADAT outputs only - 8 channels of ADAT lightpipe (up to 96kHz)
Option 2: 8 AES/EBU or S/PDIF outputs +8 channels of ADAT lightpipe, all on one board (All up to 96kHz)
An external Wordclock input is also provided (BNC connector). The AES/EBU or S/PDIF format outputs can run simultaneously with the lightpipe outputs, giving up to 16 channels of digital output for all sample rates.
Focusrite Compression
The unique sound of Focusrite compression is considered by many top industry professionals as the key to achieving a clean and controlled mix, with all the punch and clarity that can make the difference between success and failure. A Focusrite only sounds like a Focusrite because every audio processing section is powered by a unique Focusrite Class A circuit design. We do not employ any standard off-the-shelf VCA components. Each stage of the Platinum compressor is optimised for both design and component performance, achieving the smooth and pleasantly warm characteristic for which Focusrite has become synonymous.
Class A and Compression
All dynamics processors introduce distortion as a by-product of the effect being generated. At Focusrite, we accept this reality and approach the problem by making a conscious choice regarding the type of distortion generated. Standard VCA designs generate predominantly third-order harmonic distortion, which is the most obvious form of distortion, with even small amounts seriously colouring the audio being processed.
Focusrite A/D's
With converters, as with many other things in life
It’s not how big it is, but what you do with it that counts. Whether running at 48K, 96K or 192K, or at 16, 20 or 24bit rates, the converter specifications alone are no measure of the quality of the record signal path. Rather, it is a combination of both the converter specifications and the quality of the system that supports it. Focusrite A/D converter cards are designed to meet the absolute maximum design specifications possible for the converter chip-sets used. However the real benefit comes from using a recording system in which the ADC is included within the closed environment of a single box. The integral closed environment allows a shorter record path to digital, with no unnecessary analogue connections out of the Focusrite box to the input of the recording equipment. (The receiving equipment will also certainly include more analogue circuitry in the form of gain/trim stages before the external ADC, only further lengthening the record path.)
A further benefit of a single, closed environment relates to the level of unwanted noise in the vicinity of the converter circuitry. Because the Focusrite unit operates as an analogue device right up to the point of the ADC, the environment within which the converter operates is extremely quiet and controlled. It also does not contain extraneous clocks or other sources of digital noise, which exist within many digital desks and multi I/O DSP environments, any of which may further contribute to the lack of clarity and accuracy.
So, innovative circuitry around the converter, the operation of the circuitry within the host unit, the shorter signal path and a quieter operational environment, mean that Focusrite optional A/D converters offer an immense level of performance against price.