{"id":17829,"date":"2023-05-11T18:20:00","date_gmt":"2023-05-11T22:20:00","guid":{"rendered":"https:\/\/splice.com\/blog\/?p=17829"},"modified":"2025-03-28T12:59:46","modified_gmt":"2025-03-28T16:59:46","slug":"what-is-a-di-box","status":"publish","type":"post","link":"https:\/\/splice.com\/blog\/what-is-a-di-box\/","title":{"rendered":"The DI box: What it is and how to use one"},"content":{"rendered":"\n

Illustration:<\/strong> Filip Fr\u00f6hlich<\/strong><\/a><\/p>\n\n\n\n

If you\u2019re in and around recording studios, concert venues, or guitar players\u2019 households, there\u2019s a good chance you\u2019ve heard of a DI box before.<\/h2>\n\n\n\n

But if you primarily make music on the computer, there\u2019s a good chance you don\u2019t know what exactly it is or what it does. In this article, let’s talk a little bit about what a DI box is and when you would want to use one.<\/p>\n\n\n\n

Voice to verse\u2014anywhere. With the addition of Splice Mic, you can instantly test and record ideas, explore genres, and unlock new creative possibilities, all from <\/strong>the Splice mobile app.<\/strong><\/a><\/p>\n\n\n\n

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What is a DI box?<\/h2>\n\n\n\n

A DI box<\/strong> is a device that’s used to convert an unbalanced, high impedance signal (think an electric guitar or a keyboard) to a balanced, low impedance signal.<\/p>\n\n\n\n

DI boxes aren\u2019t new technology; they\u2019ve been in use for recording and live performance applications since the 1960s. DI stands for “direct input” (I\u2019ve also heard people say that the “I” stands for “inject” or “insertion”\u2014either way, the meaning doesn\u2019t change). A DI box can also sometimes be called a \u201cdirect box\u201d or just a \u201cDI.\u201d \u201cDirect\u201d refers to capturing a signal without using a mic; you plug it directly into the recorder. <\/p>\n\n\n\n

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How to use a DI box<\/h2>\n\n\n\n

Although they serve a fairly wide variety of use cases, DI boxes primarily serve two main functions: impedance matching<\/strong> and signal balancing<\/strong>.<\/p>\n\n\n\n

Impedance matching<\/h3>\n\n\n\n

Impedance<\/strong><\/a> is an electrical value that measures the amount of resistance to a current that’s present in a circuit. While all electronic instruments have impedance, some have more than others.<\/p>\n\n\n\n

Usually, we don\u2019t need to worry too much about impedance in the studio. This is because most audio equipment is designed to have a low output<\/em> impedance and high input<\/em> impedance\u2014in other words, your synths are manufactured to output a low impedance level, while your interface is capable of accepting a higher level of impedance.<\/p>\n\n\n\n

This isn’t the case, however, for instruments like electric guitars, which have electric pickups that generate a high output impedance. Normally, plugging a high-impedance instrument directly into a mixer or recorder isn’t a best practice. For example, let\u2019s say you were to plug your electric guitar straight into your interface. Since the guitar\u2019s output impedance is too high, your signal will be \u201cloaded down\u201d and you may experience a significant loss of treble in your sound. <\/p>\n\n\n\n

Here\u2019s where a DI box comes in: place a DI box between the signal\u2019s source (your guitar) and the destination (your interface), and the DI box converts the signal from having high impedance to low impedance, preventing you from tragically losing your high end! That said, you may have seen ‘Hi-Z’ or ‘instrument’ inputs on many popular audio interfaces;<\/a> these are specifically designed with a very high input impedance to enable you to plug these instruments directly into them without needing a DI box.<\/p>\n\n\n\n

For a more in-depth look at impedance, I highly recommend this Sound On Sound<\/em> article<\/a> by Hugh Robjohns.<\/p>\n\n\n\n

Signal balancing<\/h3>\n\n\n\n

Unbalanced cables, like common TS \u00bc\u201d instrument cables,<\/a> cannot be run very far before picking up interference from outside. This is because unbalanced cables have only a signal and a ground wire, whereas balanced cables have a positive, negative, and common ground. If you\u2019re interested in learning more on when to use balanced vs. unbalanced cables, check out our article on common bedroom studio setup mistakes,<\/a> but for this article it will suffice to say that balanced cables have some capabilities that make them more desirable in certain situations. For example, balanced cables can be run for a much longer distance without signal degradation, and can reduce electrical noise due to a function called phase inversion<\/strong>.<\/p>\n\n\n\n

A DI box is capable of accepting an unbalanced signal and turning it into a balanced signal. This means that if you need to run a balanced cable, but your instrument requires an unbalanced output, you can use a DI box\u2019s signal balancing capabilities to solve your problem!<\/p>\n\n\n\n

For example, let\u2019s say you\u2019re playing electric guitar at a big venue, where the mixer is more than 20 feet away from the stage. If you try to run an unbalanced signal from your guitar straight to the mixer, you\u2019re likely to experience electrical noise ruining your performance. Instead, you wisely decide to plug your unbalanced TS \u00bc\u201d cable from your guitar into a DI box. The DI box balances your signal, so you can run a long, balanced XLR cable from the DI box into the mixer. Now you can focus on the rest of your day-of-show problems, like getting your friends (who the promoter said he would put on the guest list) past security.<\/p>\n\n\n\n

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Extra functions of DI boxes<\/h2>\n\n\n\n

All DI boxes will be capable of signal balancing and impedance matching, but some DI boxes feature a few other bells and whistles. Two of the most common extra capabilities found on these handy bits of kit are a ground lift switch<\/strong> (which disconnects the signal from the ground, addressing ground loop hum in the signal) and a pad<\/strong> (a switch which reduces output gain by a fixed amount\u2014usually somewhere around 20 dB).<\/p>\n\n\n\n

It\u2019s also worth noting that DI boxes can be either passive<\/strong> or active.<\/strong> Passive boxes require no power, while active boxes must be powered, usually via phantom power<\/strong><\/a> or batteries. An active DI box usually has a preamplifier inside it, meaning it can handle very low-level signals and higher levels of impedance. However, a passive DI box can be more convenient since no power is required, and since there’s no power, there’s no risk of noise added by electric circuitry. A passive box will usually be fine for most applications, but if you\u2019re in the market for a DI box it\u2019s worth looking at a couple of active and passive options to best fit your use case.<\/p>\n\n\n\n

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TL;DR: When do I need a DI box?<\/h2>\n\n\n\n

To summarize, below are some of the instances in which you’d want to consider using a DI box:<\/p>\n\n\n\n