I just play the bass, I use a pick, I sometimes slap it, why do I need to know what a DI Box is!?

If you’re like me then you don’t know what the heck a bass DI box is.  Or you have an idea but don’t know much about electricity and how it affects you bass.

You can jump to our best di box review’s here, if you don’t need anymore information about DI’s.

I promise to make this article as short as possible and to use easy words so we can all understand what we’re doing.

But 2 things, depending on your type of style of music and playing, you’re going to want to read about which DI box to use.


A DI is short for its adult name ‘Direct Box’, pretty simple. And you would think that would be obvious for what the device does.  But that’s not the case.  What it does is it converts your signal from an unbalanced high-impedance output to a now balanced and low-impedance signal.

Direct Boxes are used on instruments like the bass, acoustic guitars(with pickup), Keyboards, drum machines, turn tables, DJ equipment, ipods, etc, typically things that use 1/4 cable.

Here is why.  These instruments all have an unbalanced/weak output or sometimes a hotter signal.  Unbalanced signals can pick up low buzzes, hums, radio stations, or grounding type issues and noises.

So this is where the Direct Box comes in very handy.  SO if you think of it this way, the box which is connected by a balanced XLR microphone cable goes to the sound board or mixer.  You plug into that box using an unbalanced 1/4″ guitar cable. Guitar cable in, XLR cable out/unbalanced to balanced.

OK, just so we’re not confused a signal from that box come out and into your amp, you plug into the box first.  You will still be using your amp, but to get a good balanced mix at the sound board or recording studio mixer, your signal needs to be balanced.

Grounding issues (loud buzzing sounds from your instrument/amp) DI boxes usually come equipped with a ground switch, this comes in handy.  Each new place you plug your amp into might have a different electrical current that messes with your sound cause loud buzzing noises.  You need a ground!

PRO TIP:  If you play a bass, get a DI box.  Don’t assume the venue will have one.  It’s your sound.

3 Types of Direct Boxes

Active and Passive are both in use today, and depending on the application they both have their advantages.  You see, It wasn’t until Fender came out with single-coil pickups that engineers noticed how terrible the sound was for some instruments.  That’s when they invented the active DI.  So, instruments respond differently to each, so let’s go over that.

  • Passive DI Box – Typically contains a transformer.  The most common you will find are these, they are easier to use.  You don’t need a power source or any fancy knobs.  You just plug-in and go.  Hopefully at the very least there is a ground switch.  These are cheap and extremely reliable however it is known that cheaper boxes are known to cause more noise interference issues like a hum or buzz.
  • Active DI Box – These contain an amplifier and require a power source like a 9 volt battery or phantom power.  Because of this these can provide more gain and offer a bit more complexity than the above box.  These come equipped with a few more switches than the passive.  Like, a ground switch, mono or stereo, power source, level adjustment and phantom power.  A noticeable difference is noticed when using this type of DI.
  • USB DIRECT BOX – This day and age we have a new style of instrument, the music laptop.  So like any other instrument, the sound source needs to use a DI box to balance out the connection through the lines.  How we connect to the box is from the USB of the laptop to the box using the standard USB cable.  These are high performing 24bit/96 k stereo DI.  Built in headphone amp for monitoring.  Grounding switch and pad. SO worth it if you’re a DJ or using your laptop as any other instrument.


The short answer is, YES.  You should have one and use one.  If you play your music live or record it, a DI is nice to have with you.

They are good to have for reasons like having more eq control at the board, they make your signal stronger and sound a bit more natural. Like maybe your amp is that gritty muddy sound, or it’s a little on the bright end.  Having the control at the board helps the overall sound.


In general, active electronic devices have their own power supply whereas passive electronic devices are powered by another device.

Passive pickups have a weaker signal, and could benefit from the amplification of active DI’s.  Active Direct boxes work best for instruments that have a passive signal, such as:

  • Bass(Regular, without a battery)
  • Electric Guitar

An active direct box will have a power source, usually a 9 volt battery.


Using a passive direct box for instruments that have built-in power pre-amps.  Usually, a 9 volt battery or the instrument is plugged in.

Active instruments are:

  • Bass (active)
  • Keyboard
  • Electronic Drum kits
  • Computer
  • MP3

These instruments can produce more signal so you wont need the amp that the active DI has on board.


It’s always a good idea to have a direct box in your music equipment.  Weather this is going to be for live or recording, they do help.  As a sound guy for years I always like to use a DI and a microphone if one was available.  However, I always had better luck mixing the sound from the board.




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