Prism Sound Orpheus FireWire Recording Interface
Orpheus is a FireWire multi-track audio interface for with 8 channels of analogue input and output as well as digital I/O and sync. The first two channels of analogue input can be mic, line or instrument, the next two mic or line and the last four are line inputs. Orpheus is ideal for music and sound recording, multitracking, overdubbing, stem-based mastering, analogue summing and critical listening applications.
Orpheus provides Prism Sound’s renowned performance, sound quality and state-of-the-art clock technology in a dedicated FireWire unit compatible with both Windows (XP, Vista (32 and 64bit) & Windows 7 (32 and 64 bit), ASIO & WDM) as well as MAC OS X 10.4.11 and later (Intel & PPC). Once configured with a computer, Orpheus can also operate stand-alone using its S/PDIF or AES3 I/O.
For computers without FireWire, Orpheus can also be used with Thunderbolt equipped computers via a third party Thunderbolt to FireWire adaptor.
Orpheus has line, microphone and instrument inputs, selectable RIAA Equalization for turntables, a built-in premium-quality monitoring mixer for each output providing for performer foldback and surround monitoring, concurrent ADAT and switchable S/PDIF or AES3 digital I/O plus support for outboard MIDI devices. Microphone inputs include MS matrix processing. High-performance digital sampling-rate conversion (SRC) is available for digital inputs or outputs. Dual headphone outputs are provided each with its own volume control, both monitoring the same headphone feed.
Eight analogue input channels and up to 10 digital input channels are available as inputs for your audio workstation software through the host computer’s audio driver. Similarly, eight analogue output channels, up to 10 digital output channels and stereo headphone outputs can play 20 different channels. For low-latency foldback or monitoring to headphones or main outputs, each output pair (1-2, 3-4 etc or the headphone output) can optionally be driven from the built-in DSP mixer with an individual local mix of any selection of inputs through the controller applet. All analogue inputs are electronically balanced with automatic unbalanced operation. Analogue outputs are electronically balanced with ‘bootstrapping’, i.e. level is maintained if one leg is grounded.
No-compromise, full Prism Sound audio quality
Orpheus makes no compromises on audio quality. It is the result of years of research and development into digital audio conversion and extensive dialogue with Prism Sound’s customers.
The Orpheus design brief was: Get Prism Sound quality conversion and mic preamps into a 1U box at a more accessible price point. Sound quality just wasn’t negotiable. Orpheus has the same no-compromise analogue front and back ends, with the same fully-balanced-throughout architecture, the same isolation barriers protecting the analogue from digital and computer interference.
Orpheus draws on Prism Sound’s years of experience in developing digital audio products, including its range of audio test equipment, adopted by a wide variety of clients across the audio industry from pro-audio to consumer electronics. This experience means that Orpheus is well-behaved both as a computer peripheral and an audio processor.
Reliability is vitally important in professional recording. Prism Sound has always made extensive use of precise software calibration techniques in its converters – pots and tweaks are always unreliable, so there are none.
The design team has gone to great lengths to minimise noise and interference, in particular hum. All of the analogue circuits have galvanic isolation, while the unit’s electronically balanced I/O allows it to handle common mode interference sources as well as enabling trouble-free connection to unbalanced equipment.
It is often said that THD+N figures do not always correlate well with the perception of sound quality and this is true – partly because the traditional measures of THD+N or SINAD expressed as RMS figures are rather a broad measure. With this in mind, we have taken great care to make sure that not only is the Orpheus noise and distortion spectrum beyond reproach, but the RMS distortion result measures up to the state of the art.
Standards compliant FireWire interface
Orpheus is easy to connect to your computer and to your outboard gear. For Windows XP, Vista or 7 users ASIO and WDM drivers are provided, while for Mac OS X 10.4 or later, Orpheus interfaces directly to Core Audio. For both Mac and PC platforms, there is a controller application to configure the unit and control its built-in mixer and other functions. Aside from the monitor and headphone level controls, everything else is operated solely from the Orpheus controller application. The controller software opens on-screen as a separate panel alongside your existing editing software.
Increasing standardisation is leading to more choice for those wishing to “mix and match” editing and production software with various audio interfaces. Prism Sound has taken on board the increasing importance of native processing power for professional users and the fact that software products for standard PC and Mac platforms have been greatly enhanced in recent years.
Prism Sound is probably best known for A/D and D/A converters, not least the ADA-8XR, which already provides a solution for those needing a FireWire interface. However, the flexibility and versatility of the ADA-8XR comes with a higher price tag, reflecting the fact that no other interface provides such exceptional audio performance or can work directly into Pro Tools Core/Processing cards, as well as running a concurrent DSD processor or FireWire interface.
The solution was to create a unit that is dedicated as a FireWire interface and is compatible with Windows PC and Apple Mac computers.
For newer computers with Thunderbolt ports, we have also successfully tested Orpheus with a Thunderbolt to FireWire adaptor.
Flexible Inputs and Outputs
Orpheus provides a highly integrated solution with instrument and microphone inputs, and line outputs that could be used for stereo or multi-channel monitoring and/or foldback to performers. Orpheus offers eight analogue recording channels, eight monitoring outputs, stereo digital input and output on a phono connector plus concurrent optical digital I/O ports that can interface to S/PDIF or ADAT data formats, giving Orpheus a maximum capability of 18 concurrent input and output channels plus stereo headphones.
Orpheus’ eight analogue inputs support various capabilities. Orpheus has four really good mic amps with software-controlled gain in 1dB steps, individually-switchable phantom power – and very low noise and distortion. These inputs are auto-sensing, and support microphone and line input, with digitally-controlled mic gain in excess of 60dB. Two of these inputs also support direct injection (DI) instrument connections with quarter-inch jacks on the front panel. RIAA Equalization can be selected in the controller applet on channels 1 & 2 so that turntables can be connected for archiving or sampling applications. By selecting the input type (Mic or DI) , low- or high-impedance cartridges can be loaded with suitable termination impedances. All analogue inputs have individually-selectable Prism Sound “Overkillers” built in, just as on the higher-priced ADA-8XR, to catch those fast transients. The Overkiller threshold automatically follows the operating line-up level selection (+4dBu or -10dBV). Overkillers are ideal for percussive sounds, particularly drums, where headroom can be a problem.
The co-axial digital I/O port can be switched in the Orpheus controller applet between S/PDIF and AES3 formats. This control changes the operating voltage and the Channel Status format and is complemented by two in-line adaptor leads that provide external XLR connections for AES3 devices. Other connections include MIDI in and out and wordclock sync I/O.
Orpheus can also operate in a stand-alone mode using its ADAT or co-axial digital I/O connections. Once set up using the Orpheus controller applet, the unit can be disconnected from the host computer and used independently. Orpheus will retain its settings when powered down so even if it is switched off, Orpheus can be re-powered and stand-alone operation can continue with the automatically-stored settings.
Orpheus has a powerful built-in digital mixer that can be configured from the host computer to provide foldback feeds to performers, each with their own stereo mix of workstation playback and any of the inputs.
The question of latency in computer interfaces, especially USB and FireWire boxes, is an important one. Obviously there are situations where the round-trip latency needs to be really short, like in overdubbing. The problem is that even if the latency on the interface and in the driver is as short as it could ever be, a native DAW is busy with plug-ins and other software and buffer times are probably set long. The only answer is to provide local foldback mixing in the interface. This is not new, and other products feature it, but most local mixers in competitive products are just too basic. Orpheus provides ‘console quality’ local mixing – every output has its own independent mixer, with channel strips for all inputs and workstation feeds, complete with fader, pan/balance pot, solo and mute buttons, and full metering. Strips can be stereo or mono, and the mixes are dithered with filtered coefficients, just as in a top-end digital mixer.
There is a very small residual delay through the A/D and D/A conversion process in the foldback path, mostly from filters used for decimation and interpolation. However, with the low-latency Prism Sound DSP mixer, the worst-case delay through the A/D and D/A path is only 0.5ms and is significantly less at higher sampling rates. This is generally reckoned to be small enough not to be problematic.
Although the unit’s outputs will mainly be used for monitoring or foldback, the fact that they are of such high quality makes them suitable for a range of other applications such as insertion points, analogue summing or stem-based mastering.
The eight analogue outputs on Orpheus allow monitor setups from multi-stereo up to 7.1 surround. Orpheus has a real volume knob which can be assigned to any or all of the analogue or digital outputs for use as a control room monitor control. There are two headphone amps, suitable for all types of headphones, each with its own independent volume control. As well as having its own workstation feed and mixer, the headphones can also be quickly switched across the other output pairs, which is handy for setting up.
Sample Rate Conversion and Noise Shaping
The digital output is equipped with the four Prism Sound SNS noise-shaping curves and includes Prism Sound’s renowned synchronous sample-rate conversion, allowing outputs to various external devices at other sampling rates. The sample-rate converter can be used at the outputs as well as the inputs, so as well as dealing with unsynchronised or wrong-rate digital inputs, Orpheus can also generate, say, a live 44.1kHz output from a 96kHz session. Since Orpheus also includes the full suite of the famous Prism Sound ‘SNS’ noise shapers, you can also reduce to 16-bits at mastering-house quality.
Unsurpassed Jitter Rejection
In the 1990s Prism Sound pioneered testing of sampling and interface jitter and as a result our digital audio products deliver unsurpassed jitter rejection. Prism Sound digital audio products lock up fast and re-generate ultra-stable clock outputs. Another aspect of the traditional Prism Sound converter that is retained was the clocking – it’s just as important as analogue-path considerations sound-wise. So whether it’s providing a high-quality master clock for the rest of the room, or dealing with a jittery clock from outside, Orpheus is as rock-steady as its forbears.
Over the years, Prism Sound’s reputation for audio quality has been matched by its reputation for after-sales support and technical advice. Orpheus has the benefit of that support and customers have access to one of the best technical teams in the business.
Orpheus’ front panel gives continuous visual indication of the unit’s main settings and levels, but in-depth control is managed from the Orpheus FireWire Controller applet. This runs on the DAW computer, and can be popped up whenever adjustments are needed.
The upper area of the applet shows a panel of ‘Global’ settings for the entire group of connected FireWire interfaces, and a panel of ‘Unit’ settings which is assignable to each connected unit in turn, using the enclosed drop-list. These settings are concerned with general parameters such as sync source and sample rate selection, metering and buffering modes. An ‘Identify’ button causes all the LEDs on the selected box to light, to assist with identification in multi-unit systems. To the right, there are large buttons for loading and saving setups, and for on-line help.
The function of the lower area of the applet is determined by the row of tabs above it. These tabs allow the lower area to be switched between Input and Output Setup pages, Mixer pages for each output, an ADAT metering page and a block diagram page (which contains a navigable diagram of the functions of the selected unit).
The Input Setup page is divided into individual channel ‘strips’. Analogue input strips show an indicator of whether mic, line or instrument is connected, and the remainder of the strip changes context accordingly. Line input strips show a high-resolution meter, with overload indication, and a +4/-10 sensitivity selection. An ‘OVK’ button activates the ‘Overkiller’ soft limiter, whose momentary operation is indicated beneath the meter. Instrument inputs have the sensitivity switch replaced with a slider control which adjusts the gain of the preamplifier in 1dB steps (indicated in the box beneath). Mic inputs also have a slider gain adjustment, as well as buttons for phantom power, high-pass filter and phase-reversal, as well as a mid/side (M/S) matrix function selectable per stereo pair. The digital input has a coaxial/optical selection, plus an ‘unlock’ indicator and a warning indicator for asynchronous input stream (SRC active).
The line output strips in the Output Setup page show a high-resolution meter, with overload indication, and a +4/-10 output level selection. The digital output strip has selectors for wordlength, dither mode (flat dither, or SNS 1 thru 4 noise-shaping) and (if the SRC is selected) output sample rate and sync source. Metering is also provided for the stereo headphone channel. The upper part of the page contains a row of assignment buttons for the monitor volume control, which is located on the front panel of the unit. Assigned output channels are subject to the action of the volume control, which is also indicated and controlled from the applet page. At the bottom of the page, each output pair has a DAW/Mixer selector, which causes it to be driven either directly from the respective DAW feed, or from a local foldback mixer controlled by the appropriate applet page. The headphone output also has a ‘Bus’ mode, wherein it can be switched to follow any of the other output pairs.
Each output pair has a dedicated mixer page, which is activated when the DAW/Mixer selector on the Output Setup page is set to ‘Mixer’. On the mixer page, each channel (including the master output) has a fader and high-resolution meter. Input channels can be operated in stereo or mono mode, and have pan/balance, mute and solo controls. Analogue input channels also have Overkiller activity indicators.
8 A/D Analogue input channels including
– 4 x Mic/Line inputs on combo connectors
– 4 x Line inputs on TRS
– 2 x Front panel instrument inputs on jack
– 8 D/A Analogue output channels
– 2 headphone outputs with independent volume control
– S/PDIF I/O on RCA or TOSLINK
– AES3 I/O via RCA to XLR adaptors (supplied)
– ADAT I/O mode including S-MUX
– Sync I/O on BNC
– ASIO and WDM drivers provided for Windows XP, VISTA (32 and 64bit) and Windows 7 (32 and 64bit)
– Directly compatible with CORE AUDIO on Mac OS X 10.4+ (Intel & PPC)
– Concurrent operation of ADAT and switchable S/PDIF or AES3 ports
– MS Matrix processing on mic inputs
– RIAA Equalization on inputs 1 & 2
– Prism Sound “Overkillers” limiters on all analogue inputs
– Fully-floating (isolated) balanced architecture for optimum noise rejection
– Low-latency “console-quality” digital mixer built in
– Fader, pan, cut, solo on every mixer channel
– Outputs selectable between workstation bus or Orpheus mixer
– Front-panel master volume control, assignable to selected channels
– Configurable for stereo, 5.1 or 7.1 or surround monitoring
– Built-in sample rate conversion (SRC) on S/PDIF Inputs and Outputs
– Prism Sound 4-curve SNS noise shaping on digital outputs
– State-of-the-art clock generation with proprietary hybrid 2-stage DPLL
– MIDI in/out ports