Most home studios contain an arsenal of gear that is carefully chosen. From synths and groove boxes to guitars and drums, the tools in your studio should be connected properly to work. But for some kinds of gear, making the best connection means you’ll want an extra piece of equipment—a DI box.
It’s a stage and studio staple that fixes issues in the signal flow.
However, what is a DI box? And why exactly do you need one?
In this article, we’ll explain all the things you should know about DI boxes and give recommended choices for the best ones on the market.
Let’s get started.
What is a DI box?
A DI box is a helpful tool that corrects signal level and impedance to make audio gear compatible.
The term DI stands for Direct Injection. The first DIs were constructed to allow engineers to plug electric basses and guitars straight into the studio mixing console instead of micing an amplifier.
DIs are common for those instruments as well as synthesizers, drum machines, and other gear with ¼” outputs.
Utilizing a DI you can plug these sources into an XLR microphone preamp input like those you might discover on a mixer or audio interface.
DI boxes include a transformer that electrically isolates the source from its destination. That’s the reason why DI boxes are frequently used to address signal issues like ground loops.
Why do I need a DI box?
Not all the audio sources in your home studio carry the identical type of signal.
There are other different connector types, different signal levels, and different impedances.
Your signal fidelity can get worse in case some of these qualities are mismatched.
One of the most common instances is when you connect ¼” instruments such as electric guitar and bass to a mic preamp or audio interface.
The guitar signal coming from the pickups is an excessive impedance, instrument-level signal.
The mic preamp is expecting to see a low impedance, mic level signal.
Even if you converted the ¼” and XLR connectors with an adapter, the signal and impedance mismatch would make poor sound via the preamp.
To fix it you’ll need a DI box to handle the signal level and impedance conversion in order that the mic preamp works properly.
The same goes for most kinds of gear with ¼” outputs like synths, drum machines, and samplers.
Hot tip: Some {hardware} has ¼” outputs that are powerful enough to be plugged straight into a mixer at line level. A gear like this doesn’t strictly need a DI as long as the destination has line-level inputs. However, you might find using a DI box to pass the signal via the mic preamp sounds more pleasing.
Active vs. Passive DI boxes
There are two major kinds of DI boxes—active and passive.
Passive DI boxes don’t require a power supply to work. The transformer inside shows {the electrical} operations that convert the signal.
Passive DIs work effectively for most applications and are sometimes more affordable than their active counterparts.
They may also be used with extremely strong signals since there’s no electrical circuitry to overload.
Active DIs make use of phantom power to run {an electrical} buffer circuit that makes the signal stronger and helps it maintain fidelity.
These are a good selection for low-level instruments and long cable runs.
DI vs. instrument input
Many modern audio interfaces come fitted with a ¼” input for connecting devices just like guitar and bass.
These could seem to perform the same function as a DI box, and in lots of cases, they get the job completed. However, the transformers constructed into professional-grade DI boxes can solve problems your interface’s instrument input can’t.
For instance, ground loops frequently occur between powered equipment plugged into the same source.
They make a nasty hum and buzz that wouldn’t be acceptable for recording.
Transformer-based DIs provide electrical isolation and ground lift capabilities that can eliminate ground loops.
The 8 greatest DIs for recording
With the background information out of the way, here are 10 top decisions for DI boxes to make use of in the studio.
1. Radial J48
There’s a brand that you can see in almost every discussion of DI boxes—Radial.
The Canadian manufacturer of stage and studio equipment builds a few of the most popular choices for pro-quality DIs.
Their flagship active DI model is the J48. It’s a wonderful choice for almost any application, especially recording.
2. Countryman Type 85
Another famous name in DI boxes is the Countryman Type 85. It’s an active DI with a high-quality sound for recording guitars and bass.
3. Rupert Neve Designs RNDI
Rupert Neve was a towering figure in musical tools design. His company’s DI box is one of the greatest choices available for recording.
It includes a custom transformer wound precisely to its exacting specifications for high efficiency.
4. Radial JDI
If a passive design is a better option for your application, you might think about the Radial JD1.
It features the superb Jensen transformer Radial is famous for in a roadworthy enclosure.
5. Warm Audio WA DI-A and WA DI-P
Warm Audio is a modern professional audio brand that builds reasonably priced recording gear inspired by vintage classics.
Their new WA DI range consists of the passive WA DI-P and active WA DI-A. Both feature Cinemag transformers for a smooth sound.
The unique ‘amp out’ feature lets you connect the output of a guitar amp directly to a mixer or recording interface.’
6. A-Designs REDDI
The A-Designs REDDI is the Rolls-Royce of DI boxes.
A secret weapon on bass guitar for a lot of professional engineers, the REDDI options design inspiration from the legendary Ampeg B15 tube bass amp.
If you’re searching for a premium DI tone with a lot of character, the REDDI must be on your list.
7. Radial ProDI, Pro48
Radial’s flagship active and passive DI is worth every penny, but for some producers, the price may still be too high.
If that’s the case, Radial provides a line of budget-conscious DIs based on the same technology that powers their top-of-line options.
Think about the ProDI or Pro48 if you want Radial quality on a budget.
8. BAE PDI
BAE is a famous builder of vintage reproduction mic preamps and studio gear.
Their PDI passive DI features all the quality the legendary brand is famous for at an affordable price.
It features a unique Carnhill transformer for a vintage vibe and tone.
Direct connection
A DI box is an important tool for every home studio. It doesn’t matter what kind of gear you’re connecting to, there’s an option on this list for the right sound.
If you’ve made it through this article you’ll have an excellent start for choosing the right DI.