Radial HDI

High Definition Studio Direct Box

The HDI is a studio-quality direct box designed to create exceptional recordings with any instrument, utilizing premium Jensen transformers and a unique Color control that provides an entirely new yet familiar-sounding sonic palette to experiment with.

• Dial in an amazing tone within seconds

• Blend from ultra-clean to amp-like distortion

• Smooth Opto compressor for peak reduction

• Mic and line-level outputs

• Oversized custom-wound Jensen transformer

Instant Gratification
Despite the complex circuitry housed within the unit, the HDI has an elegant set of controls that allows the musician or engineer to dial up a record-ready sound with a minimal amount of tweaking required. The Level control drives the inputs of the HDI with instant visual feedback from the responsive front panel meter, while the Color knob provides seamless blending between an ultra-clean tone and amp-style distortion and saturation, so you can add just the right amount of character and grit to your instrument. A smooth Opto compressor can be engaged to control the peaks of the input signal, and a High-Pass Filter clears up any excessive low frequencies added by the Color control. Lastly, a Presence control accentuates the highs and high-mids, providing the ability to cut through the mix with results that are sure to impress.

Looks and Personality
With its gunmetal anodized 1/4" thick milled front panel and distinctive styling reminiscent of classic outboard studio equipment, the HDI is sure to turn heads in any recording space. A custom output meter provides a level check at a glance, with oversized chrome knobs for precise adjustments and easy tweaking on-the-fly. The HDI is a stunning standalone unit, but it also comes complete with mounting hardware to install in standard 19" equipment racks. One or two HDI's can be installed side-by-side in a 2RU rack space, and like all Radial products, they are built with rugged components and designed to easily withstand the rigors of concert touring.

Behind the Design
While the HDI is incredibly easy to use - requiring only a few seconds to achieve great-sounding results - both the design philosophy and the under-the-hood processes at work are anything but simple. Click here to read an interview with the HDI's designer, W.C. "Hutch" Hutchison for an in-depth look at how the HDI came to be and what makes its circuitry so unique.

FEATURES

In
Standard ¼” TS input for mono instruments. When in use this input overrides the rear-panel ¼” Input.

Thru
¼” TS unbuffered pass-through to feed the input of a stage amplifier.

HI-Z
Adjusts the input impedance at the 1/4” inputs, similar to an older amplifier with HI and LO inputs. Lower position is 200k Ohms, higher position is 2Meg Ohms.

Level
Input level control which also allows you to drive the distortion channel of the Color control for greater saturation and coloration.

Opto
3-position switch controls an internal opto compressor circuit, providing smooth and natural dynamic control when the Color knob is set to the clean channel (7 o’clock to 12 o’clock range). Note that the Opto LED will only illuminate to indicate when gain reduction is being applied.

Color
Blends between an ultra-clean DI channel (when turned fully counter-clockwise) and a unique distortion channel that adds transformer saturation and amp-like distortion as this control is turned clockwise.

HPF
Three-position switch rolls off low frequencies to compensate for additional low end content when applying distortion via the Color control. Note that this switch only affects signal that has been processed through the distortion channel of the Color control, the HPF does not affect the clean side of the HDI.

Presence
Adds emphasis to the high and high-mid frequencies. Fully counter-clockwise is flat, turn this control clockwise for an increasingly brighter sound.

Lift
Disconnects the HDI audio ground from the chassis ground to eliminate hum and buzz caused by ground loops.

Power
On/off switch for the HDI, when powered on the Output Meter LED will illuminate.

Output Meter
Wide-range highly responsive peak meter corresponding to the signal present at the Line-Level XLR output.

Power Input
Connection for IEC power supply cable (included). Ensure the front panel Power switch is in the off (down) position before connecting the HDI to power.

-15dB PAD
Reduces the signal level at the Line-Level XLR output to avoid clipping the input stages of recording interfaces which have lower maximum input settings.

Line-Level Output
Independently isolated Jensen transformer-equipped XLR output designed to connect directly to the line-level inputs of a recording console or audio interface, bypassing the need for a separate preamplifier in the signal chain.

Mic-Level Output
Typical direct box balanced low-level XLR output, for connection to stage snakes or the mic inputs of a recording console or audio interface. This output features an additional premium Jensen transformer for isolation and signal reduction to mic-level.

Processed Output
Unbalanced 1/4” TS output that follows the tone-shaping circuitry of the HDI, allowing you to easily feed an affected signal to a stage amplifier, amp modeling unit, or any device with instrument-level inputs.

Synth Input
Mono 3.5mm input for connection to modular synthesizers. This input features a lower sensitivity to accommodate the hotter levels that modular synths typically output. Connection to this input overrides both 1/4” instrument inputs.

Input
Standard 1/4” TS jack for connection to mono instruments, mirrored on front panel input jack.

SPECIFICATIONS

Frequency response: Line Output: 1Hz ~ 100kHz +0.25/-3dB, 20Hz ~ 20kHz +/-0.1dB Mic Output: 10Hz ~ 80kHz +0.25dB/-3dB
Dynamic range: 112dB (20-20k, unweighted, referred to +25dBu)
Gain: Min Gain (Level CCW): -3dB Max Gain (Level CW): +31dB
Total harmonic distortion: 0.3% @20Hz, 0.22% @100Hz, 0.01% @1kHz (+4dBu In)
Signal to Noise: 91dB (20-20k, unweighted, referred to +4dBu)
Maximum Input: 1/4" TS: +5dBu, 3 VAC RMS, 8.4 V Peak to Peak 3.5mm: +25dBu, 7 VAC RMS, 20V Peak to Peak (Level @ 12:00)
Maximum Output: Line Level XLR: +25dBu (1% THD at 1kHz) Mic Level XLR: +3.7dBu (1% THD at 1kHz) 1/4" Processed Out: +8dBu (Approx. unity gain with Level @ 12:00)
Features: Input pad, Ground lift, HPF
Input Connectors: 1/4” TS (front and rear), 3.5mm Synth
Output Connectors: XLR Line / Mic, 1/4” TS Processed, 1/4” TS Thru
Extras: Opto Compressor: 6:1 ratio, max 8dB gain reduction HPF: 40Hz / 100Hz rolloff @ -6dB/octave
Construction: 14 gauge steel chassis, 1/2” aluminum front panel
Size (L x W x D): 8.25” x 8.25” x 3.5”
Weight: 5.05lbs
Power: 100-200VAC 0.45A ~ 50/60Hz
Conditions: For use in dry locations only between 5°C and 40°C
Warranty: Radial 3-year, transferable