ROAD TEST
Radial HDI Studio Direct Box
By Adam Gallant
Released in early 2020 , Radial ’ s HDI is its latest flagship studio DI box . Being a NAMM TEC Award nominee , it ’ s a no-compromise DI box that steps away from the conventional clean and true sound that Radial DI boxes are known for . The HDI has the ability to deliver really fabulous-sounding transformer distortion ( via a custom , oversized Jensen transformer ), as well as the very cleanest , unadulterated sounds .
In this test I ’ ll touch base on some of the unit ’ s features and talk a bit about how it performs in the studio on a few different sources .
Out of the box The HDI is a 2U , half-rack unit designed for desktop or rack-mounted use . The build quality is notably robust , with a 1 / 4-in . -thick milled gunmetal front plate , chrome knobs , and chrome switches . All of the tactile components bear a good amount of heft and all of the knobs are detented for ease of recallability . There is a well-lit and easily-readable VU meter , which has proven to be a delight to use . I have taken to re-amping material through the HDI , and having a meter to tune the signal path makes using this DI really trustworthy and fun .
On the front panel there is a 1 / 4-in . input and thru ( not processed ); Level , Color , and Presence knobs ; Hi-Z / Low-Z impedance , compression , high-pass filter , and power switches ; and a ground lift . On the back we have IEC for power , a very useful -15dB pad , separate XLR line and mic level outs , a 1 / 4-in . processed out , a modular synth input , and , finally , a second 1 / 4-in . input on the back for those looking to route in via the rear . Needless to say , a lot of features and a lot of routing possibilities .
From pristine to filthy I love committing to saturation while tracking ( when the music calls for it ). The HDI has a very pleasing distortion sound that is tube-like and void of the harshness that we sometimes associate with a solid-state-type of distortion . The flavour of the saturation goes from subtle vintage sounding to fully overdriven — a lot like a full-bodied amp with high gain . With the Color and Presence knobs all the way down , the DI is void of any audible saturation , and performs in a more conventional way . Turning up the Presence knob gives a clean-sounding amp feeling to the signal , while the Color knob does the heavy distortion lifting .
In use This box is very simple and easy to use and getting a great tone takes very little fussing about . I tended to push the Color and Presence aggressively with DI guitars into my interface . The distortion effects from this DI are a joy to play through . It has a familiar amp-like feeling and the saturation is not simply on or off , but rather a gradual slope into saturation depending on how the Color and Presence knobs are parked .
The Opto circuit is a compressor circuit that can be engaged via a three-way switch on the front panel . It is designed to help contain sharp transients from things like slap bass , as well maintain the apparent loudness when you ’ re dialing in the Color knob . The compression has a fixed attack and release , and offers two switchable threshold options . I found myself leaving the Opto circuit engaged almost all of the time . No noticeable grabby-ness or ducking was audible from this circuit , just subtle and pleasing leveling .
We used the HDI primarily on guitars , reamping guitars , and on bass DI . For the most part , I found myself reaching for the HDI for DI guitar parts in rock and pop music . I ’ ve also taken to re-amping vocals and keyboard pads through a Roland Space Echo and the HDI has made its way into this path for its ability to shave off transients and warm up source material . The routing for this particular setup was out of my interface via a re-amp output , into the HDI , then out of the back of the HDI via the “ processed out ” and finally into the instrument input on the front of our Roland RE-150 Space Echo . The results were very satisfying and the HDI is the only DI box I ’ ve used that imparts a bit of fun and inspiration .
Radial ’ s HDI is trustworthy and fun to use . Amazing work from Radial and designer W . C . Hutchison on this fabulous box . I suspect we ’ ll see them popping up in studios in the same way we see Radial ’ s DI boxes on the vast majority of stages around the world .
Adam Gallant has worked in all facets of digital audio production , from music composition to location and post audio for television and film . He currently owns and operates The Hill Sound Studio in Charlottetown , PE .
24 CANADIAN MUSICIAN