This invaluable bit of kit continually flies under the radar yet faithfully serves and services both engineers and musicians a like pretty much every single live gig or studio session.
Without doubt one of the most vital pieces of gear for live or studio environments is the direct box or DI box. Perhaps its that they’re not the most glamorous or exciting piece of gear one can acquire, they are by nature a utility item of the pro audio world and don’t by any means attract the same level of GAS as say an outboard preamp, compressor, guitar pedal, amp or even plugin might, yet without them well, we’d be screwed!
For those not already familiar put simply, a DI box takes an unbalanced signal say from a keyboard, synth or sampler or a high impedance signal from an acoustic, electric or bass guitar and converters this signal into a balanced low impedance mic level signal which can then be plugged into a mic preamp of a mixing console. It’s pretty simple stuff but you may be asking yourself why that’s so important.
Read up on all the latest features and columns here.
Aside from the obvious connectivity issues that typically present when attempting to plug one of the aforementioned instruments which typically have a 1/4” connector into a mic pre, which typically have an XLR connector, the more prudent issue here is that of a balanced and unbalanced signal, with the prior being the standardised signal in pro audio and associated gear.
A balanced signal has a couple of big benefits in both live and studio environments. Firstly, a balanced signal is far less susceptible to external noise and interference such as RF, thus leaving the audio signal travelling along a cable unaffected. The second advantage being that much longer cable can be used without the worry of said potential interference, loss of signal strength or frequency response, which means running long cable lengths (of up to approx 100 metres) from say stage to the front of house mixer or from an iso booth or live room in a studio into the control room.
There are two main types of the DI box, passive and active and you’d be forgiven for asking what the difference between them is, let alone which one is better, as this dependant on the situation and type of instrument. A typical rule of thumb is if the instrument is passive, say a passive bass or acoustic guitar, an active DI is going to serve this instrument well, with great headroom, clarity and openness in its frequency response, particularly in the top end. If a sound source is active such as a bass guitar with a 9V battery powering its pickups or an instrument running at line level such as a synth, keyboard, sampler or DJ mixer, a passive DI is generally well suited to handle these “hotter” sources.
With so many DI’s available these days, it can get pretty overwhelming trying to figure out exactly what may be best for your needs and whether spending some extra coin on a more expensive DI box is really going to yield measurable benefits. We’re going to highlight a few of our top picks ranging from more affordable “industry standard” units for both live and studios settings through to a couple more expensive ones more tailed for studio use, so let’s dive in.
Radial Pro DI Passive DI Box
Easily one of, if not the most widely recognised brands on the planet when it comes to pro audio and particularly direct boxes, Radial’s Pro DI Passive DI is a direct box engineers are all too familiar with. There are only but a few DI boxes one expects to see in a venues prod spec or even a studios gear list and this DI is absolutely one of them. A few words spring to mind when describing a Radial DI – rugged, reliable, clean. One thing you don’t want to ever be thinking when it comes to using a DI is “will this thing fail on me”, and that’s just something most of us don’t think of when plugging into a Radial.
This compact forest green coloured box is incredibly simple to use, with both input and thru put on 1/4” jacks, with a -15dB pad to trim down spicy signals, with the other side housing a male XLR low-Z out rated at 600-Ohms and a ground lift button. Made in Canada and built like a freaking tank, I’ve personally never had an issue with a Radial DI and always trust them to do what they do best – be a DI box. Very affordable given the build quality and reliability which is second to none. What goes in simply comes out with these passive units, and with such clarity and transparency. It just does what it says on the tin.
Warm Audio Direct Box
Warm Audio have become well respected for their faithful recreations and inspirations from of some of the most iconic pieces of pro audio equipment ranging from legendary microphones, preamps/EQ’s compressors and guitar pedals without breaking the bank. The Warm Audio Direct Box Passive takes all of these design principles and high quality components and packs them into a slick enclosure fit for stage or studio. A no nonsense design sporting Class-A components and a custom-wound CineMag USA PUTPUT transformer, this passive DI box adds a touch of studio class to sound sources.
A switchable instrument or amp out input allows for a wide variety of input source possibilities, and a phase switch allows older equipment or “other out of phase” sources to be quickly dealt with on the input. The variable pad ranging from -3dB – -30dB provides plenty of available attenuation if required. Given the price, quality of components, overall build quality and wealth of features, Warm Audio’s Direct Box Passive is a worth a look for those wanting a classy and effective passive box for their stage or studio needs.
Mooer Micro DI Box
Guitar pedalboards are typically a limited realestate affair, with more pedals crammed on a board what makes logical sense. Often you’ll need to be get that signal out to a mixing console.
Mooer have become quite well known for making compact guitar pedals that bat above the average given their slender price point, with their Micro DI pedal being no exception. Housed in very compact enclosure, the Mooer Micro DI is a 9V powered pedal with 1/4” input jack with both XLR balanced out and 1/4” unbalanced out as well as a ground lift button. A variable gain switch ranging from -20dB, 0dB and +20dB provides some nice flexibility and the cabinet stimulator adds a nice touch of added dimension to a pedalboard’s sounds without needing to lug the guitar cab to every gig. A handy option for those needing a DI box that fits comfortably onto the pedalboard.
Radial J48 – Active
Built for the rigours of the live stage and studio, Radial DI’s have become synonymous with live venues, touring riders and studios all around the world. With bullet proof designs and pretty great price points, Radial are indeed a brand engineers have become reliant upon.
With a plethora of both passive and active designs across their range, the J48 is Radial’s mid tier active DI box with a few nifty features to keep both musicians and engineers happy, particularly in situations where gear is slim and things need to be sorted at the sound source quickly. Aside from the typical 1/4” input and thru and XLR output, -15dB pad and ground lift, all of which are standard features at this point, the J48 also provides the ability to flip polarity 180-degrees, engage a low cut filter at 80Hz and merge stereo sound sources summing them to mono on the output when utilising both the input and thru jacks. Being an active circuit and a meticulously designed one at that with high quality components, there’s whopping amounts of headroom available providing the most clear and detailed reproduction of any sound source. For the price and feature set, the J48 is a superb option for those looking for a rugged, reliable and affordable active DI for live or studio with a few well thought out features to keep you out of trouble.
ACME Motown DI WB-3
Where so much inspiration was drawn not only domestically in the US but also across the pond, in the 1960’s Motown Records reined supreme. Aside from their artist roster reading like a who’s who of music royalty, the Motown band was heavily responsible for some of the most iconic arrangements, performances of the era.
From the beginnings in Detroit, Michigan much of the Motown sound was captured with relatively simple equipment, employing effective recording techniques, with one piece of gear designed by one of Motown’s in-house engineers at the time imparting a heavy influence on these records – the DI box. Think of any James Jamison bass line and you’d have heard one of those DI’s. The distinct passive design featured unique transformers which imparted a specific harmonic distortion which became synonymous with the Motown band’s sound.
Fast forward to the 2010’s with ACME Audio getting hold of some original vintage transformers, the ACME Motown DI WB-3 was born. Staying true to the original design, the WB-3 delivers that classic 60’s Motown vibe in spades, but with a couple of modern tweaks to make this beast of a direct box a real workhorse for todays studio and stage settings. A 60dB attenuation dial allows for perfect level tweaking for hotter line level instruments without overloading the transformer. This can also very handily work in reverse if using this box for re-amping purposes which is pretty awesome! The usual ground lift, parallel inputs and XLR male out are all complements of this rugged custom made steel enclosure finished in a rather fitting military green. Whilst tonally it may not be perfectly suited for every single scenario in the studio or stage, if you’re looking for a vibey, vintage styled DI box that sounds like Motown, this is the DI box for exactly that.
Rupert Neve Designs RNDI
An absolute icon of the pro audio world, Rupert Neve got his start back in the late 60’s and early 70’s building some of the innovative recording equipment the world has ever known. Now considered the gold standard of vintage consoles, his original designs have inspired countless others, with some of his pre amplifiers and EQ modules being some of the most revered and copied in the world. Having taken his name and inherent designs across numerous companies over the decades, Rupert Neve Designs is the the last company Rupert was directly involved in before his passing in 2021.
Although more well known for his preamp, EQ, compressor and recording console designs, Rupert Neve Designs certainly didn’t shy away from the humble DI, designing one of the most elegant and sweet sounding units available today. The RNDI’s sound is indeed unique due to its custom transformers and Class-A biased discrete FET amplifiers, designed by Rupert Neve himself of course. Capable of reproducing the true depth and dimension of instruments, every nuance and harmonic detail is magnificently retained giving them a larger than life sound that other DI’s just can’t quite muster. The RNDI’s incredibly high headroom input of +21dBu can handle serious line level signal without a pad, and when in speaker mode can handle a full output of a 1000-W power amp (92 Vrms or 266Vp-p) for connecting an amplifier to the RNDI and utilising the THRU output to feed a speaker.
Simple features and connectivity without any fluff, its abundantly clear that the true magic of the RNDI lies under-the-hood, where it should be. Definitely not a cheap exercise but worth every penny, the RNDI is one of a kind professional DI capable of the most demanding live and studio tasks. Its a Neve, need I say more?
Keeping Things Direct
Like most gear of the stage and studio, one just isn’t enough and this couldn’t be more true of the humble DI box. Whilst there’s certainly different direct boxes suited for different needs having at least one option is a must. Whether it a simple and efficient passive box, a vibey vintage inspired unit or a larger than life truely professional workhorse, whatever your flavour and whatever your budget a DI box is guaranteed to serve you well and keep you out of trouble on the stage or in the studio more times than you can count.
Keep reading and hearing it from the horse’s mouth at Radial Engineering.
