by Lyubomir Dobrev | Approximate reading time: 2 Minutes
Radial Engineering HDI front

Radial Engineering HDI front  ·  Source: Radial Engineering


Who else but Radial Engineering could deliver such a hi-end DI box? The company’s love for everything DI has culminated in the release of its latest flagship DI box, the HDI.


High Definition Studio Direct Box

The new Radial HDI is unlike any DI box you may have seen before. The presence of the VU meter alone indicates that this is a piece of gear that is more than just a mere signal transformer. In fact, the HDI also comes equipped with a saturation circuit, as well as an opto compressor, adding warmth and smoothening out the audio signal passing through it.


A custom-wound Jensen transformer is at play here, along with a minimalist, but precise set of controls. You connect using the In/Thru 1/4-inch jacks located on the front panel. You can overdrive the HDI’s inputs using the Level control, with feedback which is presented by the VU meter. With the Color knob you can blend between tube amplifier-style distortion and saturation, and the clean DI signal. The Presence knob provides a high and high-mid frequency accent for a boost in cut and clarity. All in all, the HDI is as much of a tone box as it is a DI, and I for one, think this makes for a seriously promising combination.

Although it can be used as a standalone desktop unit, the HDI is sized appropriately for rack mounting as well, and ships with all the hardware necessary to install up to a pair in 2U of rack space. It’s worth noting that the principal designer behind the HDI, W.C. “Hutch” Hutchinson, is Radial’s lead hardware designer and this interview with him, published as part of the HDI’s promotion, is incredibly illuminating.

Radial Engineering HDI rear

Radial Engineering HDI rear · Source: Radial Engineering

Price and availability

Priced at USD 800, the HDI is certainly not the cheapest unit out there. But I trust Radial’s marketers more than I do my own understanding of fair pricing in this case. If you want to try one out for yourself, the unit is now available from all Radial dealers.

More information

Radial Engineering HDI front

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