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Metric Halo ULN-8 Digital Audio Processor  From Metric Halo

An all inclusive interface that has high quality preamps, converters, monitor management, and also includes Metric Halo's DSP plugins.

Metric Halo

Manufacturer's Description from Metric Halo

At Home in Any Situation

ULN-8 is the perfect tool for capturing audio wherever inspiration hits, in the studio or on the road. Well suited to any recording situation, you can record and edit on the road, in the hotel, on the airplane, or wherever inspiration hits. Use 3 ULN-8s chained together for 24 tracks of live concert recording with processing on all channels in 3 rack spaces. Location sound engineers can now capture the moment — anywhere, anytime.

When you’re done recording, use the ULN-8 in the studio as an extremely high quality audio interface to transfer your tracks into a DAW. You’ll be amazed at the sound of this box! And weighing only 6 pounds, and a little larger than a laptop, you can be the first one out of the gig, with no hassle.

The ULN-8’s archival grade inputs and outputs, coupled with Metric Halo’s exclusive Character processing, provide flexibility and sound quality unavailable on any other interface. You can transition from a wire-with-gain to a gooey tube pre with one click of the mouse, and every input can have the right character for the material you are recording.

The ULN-8 is the only unit in its class with an on-board processing engine that supports fully instantiable processing, allowing you to use Metric Halo’s world-renowned signal processing effects without sacrificing your computer’s processing power or introducing any additional latency in your monitor path. From MIOStrip to HaloVerb, the ULN-8 comes with a full +DSP license that provides all the basic production processing you need — and more. And remember, this one rack space audio interface has the ability to run entirely from any DC power source (16V-30V), making it truly and completely mobile.

Organically Scalable

A unique feature of the Mobile I/O system is that MIO’s work well individually or as a group. Mix and match ULN-8 with 2882 and ULN-2 units to create a system that meets your needs for track count and preamp power. Adding a unit to the system organically increases the DSP power of the system, so that your DSP always scales with your I/O. Break your system up for small gigs when playing out or add the units of your mates to build a huge system when required. By standardizing on the Mobile I/O platform, each member of the band can have ultimate quality while working alone, and the band can have huge track counts when playing together. You can’t lose!

Stand-alone Operation

Flexible signal routing and sophisticated patch and preset management systems as well as a comprehensive set of front panel controls are also featured in the ULN-8. The ULN-8’s front-panel controls allow the unit to function equally as well as a stand-alone Mic Pre/Converter system. In standalone mode, the ULN-8 operates with the converters directly routed to and from the AES I/O, and the analog domain sends allow purely analog operation of the preamps.

As a standalone converter, the ULN-8 provides a 24bit/192kHz eight channel front-end with 8 world-class boutique-quality ULN mic pres for any recording system. It also functions seamlessly as an analog monitor controller, making it ideal as a digital headphone amp and studio monitor controller.


The ULN-8 supports a variety of applications. For studio recording, it provides a very high quality interface to a DAW, offering sound processing or simple file transfer between workstations. Its exceptional sound quality makes it perfect as any studio’s primary analog to digital conversion and monitoring chain. Songwriters and engineers can use the ULN-8 to record and edit on the road, in the hotel, while traveling, or anywhere that inspiration strikes.

The ULN-8 is suitable for broadcast applications, too. It offers instant playback of 8 individual stereo sends for music cues or sound effects, or smaller numbers of surround stems. The compact package and portable power features mean that the unit can go anywhere users need to work, and make on-site fixes or edit location recordings without the need to send files back to the studio, saving valuable time before air.

In the live performance arena, in addition to operating as a remote recorder for archiving performances or to play out backing tracks and musical cues, the ULN-8 can operate as a soft-synth mixer and I/O interface.

ULN-8: Built upon the 2d DSP Processing Platform and MIO Console 5

The ULN-8 is built upon the 2d Card — a massive DSP processing engine that forms the nerve center of the ULN-8. The 2d Card provides a substantial amount of DSP power to drive the zero-latency mixing and processing environment that is integrated in the ULN-8 and also provides 8 channels of 192k AES I/O.

Future Proof

In 2001 we introduced the 2882 and called it “Future Proof”. Nine years later, while the competition has obsoleted multiple generations of products, the 2882 is still arguably one of the best FireWire interface available on the market... until the introduction of the ULN-8. In 2003, we released the ULN-2, with the finest preamps available in any interface... until the introduction of the ULN-8. With the release of the 2d Card and v.5, we delivered yet again on our commitment to making “Future Proof” products that stand the test of time. The ULN-8 is the next entry in our line-up of Future Proof products.

While other manufacturers churn you with the special of the day, we build products that preserve your investment and deliver for you year after year and project after project. It is our philosophy and we take it seriously.

Includes the Integrated v.5 Mixer

Included with every ULN-8, the v.5 Mixer is a completely customizable mixing engine. You can create custom mixers either from scratch or start with any of the templates we've included to get you started quickly. With the v.5 Mixer, your ULN-8 can be a mastering console in the morning, a tracking console in the afternoon, and a live sound mixer/recorder in the evening. Whatever the application, you can configure an elegant custom setup.

Not a mere computer interface cue mixer, the v.5 Mixer is a sophisticated Digital Console built into the the ULN-8. With support for mono to 7.1 mixing, multiple busses, arbitrary sends, insertable zero-latency plug-in processing, completely customizable mults, and Metric Halo’s exclusive Character, the v.5 Mixer is limited only by your imagination. And, it is completely phase compensated, no matter how complicated the routing is.

“I have the ULN-8 wired into my rack and I use it every single day. The Metric Halo v.5 software/hardware is like having an analog console in a 1-U box. The combination of hardware and software is unmatched in it's routing flexibility. With processing available on every track, I can mix anywhere!”

— Charlie Pilzer
Grammy Award winning Mastering Engineer and Producer

Latency-Free, Time-Aligned Mixing Architecture

The v.5 Mixer is based upon the +DSP graph technology originally designed for +DSP. Since the +DSP graph provides infinite routing and multing capabilities with integrated latency compensation, the addition of full access to all I/O resources means that everything can go everywhere in the ULN-8, with the unique benefit that all signal paths are automatically time-aligned. This has incredible implications — you can route anything anywhere and never have to worry about routing delays. All sends and busses are automatically realigned with the primary bus, bringing back analog simplicity to parallel routing, with digital simplicity in set up and recall.

The v.5 Mixer manages all of the plug-ins and connections within the DSP for you. So, even though you may be creating an incredibly complex network of plug-ins with many mults and bus to bus routes, the user interaction required for you to control the system is simple and direct.

The v.5 Mixer works as complex routing manager, adding plug-ins (including mixer plug-ins) to the DSP based upon your configuration commands. Because the DSP engine automatically configures the runtime environment to compensate for routing latency in the configured DSP graph, you can rely on the fact that bus to bus routes all arrive with no routing latency. This allows you to configure sub-mixes and stems, including sub-bus processing, without having to worry about phase-cancellation problems or other latency related issues.

“The MIO v.5 Console and 2d Card’s routing capabilities are unmatched, its DSP processing unrivaled, and its familiar mixer interface ensures that this power and flexibility is easily accessible…” — Orren Merton
Author of Logic Pro 8 Power

Direct Insert of Plug-ins

With the v.5 Mixer, you can now take advantage of a sophisticated direct insert model. Just insert the plug where you want to process the signal. Done!


v.5 Mixer Direct Plug-in Insert (in the inserts!)


Of course, with the included +DSP license, you are not limited to simply putting plugs in inserts and simple linear routing of Plug-ins. You can always insert a +DSP graph in any insert in the mixer to add a routing playground, allowing you to split, mult, parallel and feedback signals to your heart’s content. And then you can save the graphs as your own “Secret Weapons” - instantly instantiable with two mouse clicks.

“…I find myself ‘mixing into’ the ULN-8 as if it were a high-end console with a quality channel strip and limiter on each channel.  The Character processing on each channel does a great job of adding the vibe of various tube and transformer inputs to the mix and as always, the huge assortment of Metric Halo plug-ins sound great and are really easy to use…” — Jerry Schroeder

Multi-Bus Mixing

The v.5 Mixer allows you to create an arbitrary number of busses (limited only by the capabilities of your hardware) — each of which can be used as a master bus (routed to an output) or an aux bus (routed to other busses). Each bus is dynamically adjustable from mono to 7.1 surround. The busses can be mapped directly onto the main control UI or driven by sends. Basically, make the mixer what you need it to be. And multiple busses of multiple types are supported at all sample rates. Unlike some other products on the market, all inputs can be routed to all busses (even mults of any input), so you won’t be limited in what you can mix.

v.5 Multiple Busses, Multiple Types, and Sends
“…With the ULN-8 and the v.5 Mixer it's like the MIO Console's gone from black and white to Technicolor. First of all, the routing is simple because — just like in a hardware console — all the functionality of the mixer is incorporated into the channels themselves. Input assignments, trims, EQ, effects, pans, output assignments: all in one place. Sends and sub-mixes pop up as floating auxiliary mixers. And the console is completely customizable – from the numbers of inputs and outputs down to the colors of the strips themselves…” — Lolly Lewis
Transparent Recordings


As mentioned above, any input can be sent to any bus. Sends are simply inserted in any insert slot, which means that you can send pre or post processing. Each send can be pre or post fader, so it can track the mix of the main UI or it can be used as a completely independent send. Every bus in the system can be returned to any other bus in the system, so you can use the busses as internal auxes, mix-minus feeds, PFL busses, etc. Anything you can think of, you can accomplish with the flexible routing engine in the v.5 Mixer. The v.5 Mixer provides an innovative send window that gives you a consolidated view of all the sends for the selected bus with a full sized fader for the send level, per-bus solos and channel mutes, and support for any width send bus (that’s right — you can send to a surround bus!).

v.5 Sends Window


Metric Halo

About Manufacturer

Metric Halo provides the world with high-resolution metering, analysis, and processing solutions with award winning software and hardware. As an industry leader, Metric Halo has developed a product line so powerful and versatile, its applications range from live sound reinforcement, CD/DVD mixing and mastering, film and broadcast production to forensic science, airline safety investigation, medical research, and designing the next generation Ferrari and BMW automobiles.


ULN-8 Specifications


Preamp Rails ±15.8 Volts
Analog Rails (low power) ±9.9 Volts
Analog Rails (high power) ±12.6 Volts
Phantom Power 48 ± 0.1 Volts
Max Phantom Current Per Mic 10 ma
Maximum I/O Levels (Balanced)
Peak Line Output @ 0 dBFS (no jumper/low power) +18.5 dBu
Peak Line Output @ 0 dBFS (output jumper/low power) +22.0 dBu
Peak Line Output @ 0 dBFS (output jumper/high power) +24.5 dBu
Analog Send Max Output +21.5 dBu
Mic Pre Max Input +20 dBu
Line In Max Input +24.5 dBu
Output Impedance 5 Ω
Monitor Controller
Nominal FS output (Balanced) Output Jumper Off -19.0 dBu
Nominal FS output (Balanced) Output Jumper On -12.0 dBu
Maximum Output Same as Line
Gain Range -96 dB to +30 dB
Gain Precision ±0.05 dB
Gain Step 0.5 dB
Mic Pre Input + ADC
Input Impedance 3.3 kΩ
Dynamic Range (-60 dB, flat 0-22.05 kHz, typ) 115 dB
Dynamic Range (-60 dB, A-weighted, typ) 118 dB
Noise Floor (flat 0-22.05 kHz, typ) 115 dB
Noise Floor (A-weighted, typ) 117.9 dB
Gain Range -22 dB to +91.5 dB
Gain Precision ±0.05 dB
Gain Step 0.5 dB
THD D/A/A/D loop @ -12 dBFS 0.0007 %
THD D/A/A/D loop @ -12 dBFS +12 dB Gain 0.0015 %
THD D/A/A/D loop @ -0 dBFS 0.0023 %
Crosstalk @ 1kHz -110dB
IMD 1k component (19 kHz/20kHz @ +8dBu) -104 dBu
EIN @ 60 dB Gain (150Ω Source Impedance) -130.50 dBu
EIN @ 60 dB Gain (0Ω Source Impedance) -133.25 dBu
Analog Send Calibration (ADC = 0 dBFS) +21.5 dBu
Phantom Power (Switchable Per Channel) +48 Volts
Mic Pre + ADC Frequency Response
+0/-0.1dB @ fs = 44100 Hz 8.9 Hz - 20.5 kHz
+0/-1.0dB @ fs = 44100 Hz 2.9 Hz - 21.0 kHz
+0/-0.1dB @ fs = 96000 Hz 8.9 Hz - 43.9 kHz
+0/-1.0dB @ fs = 96000 Hz 2.9 Hz - 45.4 kHz
+0/-0.1dB @ fs = 192000 Hz 8.9 Hz - 42.1 kHz
+0/-1.0dB @ fs = 192000 Hz 2.9 Hz - 64.7 kHz
5° low-end in-channel phase deviation point 20.0 Hz
Interchannel phase 0 Hz - 20 kHz < ±0.05°
Crosstalk from SMPTE Input < -142 dB
Line Input + ADC
Input Impedance 10 kΩ
Dynamic Range (-60 dB, flat 0-22.05 kHz, typ) 115 dB
Dynamic Range (-60 dB, A-weighted, typ) 118 dB
Noise Floor (flat 0-22.05 kHz, typ) 115 dB
Noise Floor (A-weighted, typ) 117.9 dB
THD D/A/A/D loop @ -12 dBFS 0.0005 %
THD D/A/A/D loop @ -0 dBFS 0.0015 %
Crosstalk @ 1kHz -127 dB
IMD 1k component (19 kHz/20kHz @ +8dBu) -104 dBu
Gain Range -12 dB to +31.5 dB
Gain Precision ±0.05 dB
Gain Step 0.5 dB
Line Input + ADC Frequency Response
+0/-0.1dB @ fs = 44100 Hz 5.7 Hz - 20.5 kHz
+0/-1.0dB @ fs = 44100 Hz 1.8 Hz - 21.0 kHz
+0/-0.1dB @ fs = 96000 Hz 5.7 Hz - 43.9 kHz
+0/-1.0dB @ fs = 96000 Hz 1.8 Hz - 45.4 kHz
+0/-0.1dB @ fs = 192000 Hz 5.7 Hz - 42.1 kHz
+0/-1.0dB @ fs = 192000 Hz 1.8 Hz - 64.7 kHz
5° low-end in-channel phase deviation point 10.7 Hz
Interchannel phase 0 Hz - 20 kHz < ±0.05°
Crosstalk from SMPTE Input < -142 dB
Input Processing
M/S Decode Instantiable
Parametric EQ Instantiable
Dynamics Instantiable
Limiting Instantiable
Character Instantiable
Transient Control Instantiable
Reverb Instantiable
Delay Instantiable
Nearly Infinite Combinations via +DSP Instantiable
Output Processing
M/S Encode Instantiable
Parametric EQ Instantiable
Dynamics Instantiable
Limiting Instantiable
Character Instantiable
Transient Control Instantiable
Reverb Instantiable
Dither Instantiable
Mix Foldown Instantiable
Signal Generation Instantiable
Nearly Infinite Combinations via +DSP Instantiable
Front Panel
Indicator LEDs (Bicolor) 495
Meters 16
Segments per Meter 15
Channel Encoder Knobs 8
Encoders Have Shaft Push Buttons Yes
Monitor Controller Encoder Knobs 1
Monitor Controller Mute Yes
Monitor Controller Dim Yes
Indicators Per Encoder 16
Sample Rate Indicators 6
Clock Source Indicators 4
AES Clock Source Indicators 4
AES Lock Indicators 4
AES Input Signal Indicators 4
AES Output Signal Indicators 4
System Lock Indicator 1
Firewire Indicator 1
Front Panel Modes 14
Headphone Output (Dedicated DAC) TRS Stereo
DI Inputs (2) TRS Balanced
DI Input Impedance 10 MΩ
DI Input Fixed Gain (Jumper Selectable) 0/10/20 dB
DI Input Variable Gain -12 dB to 31.5 dB
Power Switch (Jumper Defeatable) Toggle
Back Panel
MIDI Connectors (In and Out) 5-Pin DIN
SMPTE Connectors (In and Out) Balanced TRS
Word Clock Connectors (In and Out) 75Ω BNC
AES Connector (8 Channels In and Out) DB-25
AES Connector Pinout Tascam/Digidesign Digital
Mic Input Connector (8 Channels) DB-25
Mic Input Pinout Tascam/Digidesign Analog
Line Input Connector (8 Channels) DB-25
Line Input Pinout Tascam/Digidesign Analog
Send Output Connector (8 Channels) DB-25
Send Output Pinout Tascam/Digidesign Analog
Line/Monitor Output Connector (8 Channels) DB-25
Line/Monitor Output Pinout Tascam/Digidesign Analog
Line/Monitor Mult Output Connectors (Analog 1/2) TRS Balanced
FireWire Connectors (2) 1394a 6-Pin
Power (Unswitched) 2.1mm Coaxial
Power (Switched) 4-Pin XLR
Security Slot Kensington
Driver CoreAudio Mac OS X
Mac OS X 10.3.9 or newer
Architectures PPC, Intel
MIO Console Included
Record Panel Included
LTC Decoder Included
Mixer Included
+DSP License Included
Voltage 14v - 28v
Power 32 Watts
FireWire Bus Powerable No
Passes FireWire Bus Power Yes
Supplies FireWire Bus Power No
External Supply (Input) I00-240VAC
External Supply (Max Input Current) 1.2 A
External Supply (Output) 24 VDC
External Supply (Max Output Current) 2.0 A
External Supply Connector 4-Pin XLR
Material Powder Coated Aluminum
Fasteners 3mm Phillips Head
Weight 6 lbs
Weight 2.7 kg
Dimensions 17" x 13" x 1.72"
Dimensions 432 x 330 x 44 mm
Rack Ears (included) Powder Coated Steel
Rear Rack Mounts Available





ULN-8 Product PDF