Here you will find home recording news, tips and articles as well as reviews of new recording gear and software. Revolution Audio Canada exists to spark the home studio uprising by any means possible!
What is a DI box?
A DI box aka Direct Inject or Direct box is a tool we use in the studio to bring a signal from an instrument (guitar, bass, keyboards) directly into our recording system.
An audio engineer (or home recording enthusiast) will use the DI box for silent recording, as a backup or to process along with a microphone on an amplifier.
Connections
The DI box typically has 3 input and output connections.
1/4" TS instrument input - electric guitar or bass connects here
XLR-M balanced output - connects to mic preamp
1/4" TS Thru - Continues the input path to connect to an amplifier.
For example, the DI box would be connected between an electric bass and audio interface mic input. The clean bass signal can be recorded without the need for an amp.
Functions
The DI box has a few functions.
Impedance change - The instrument circuit will react correctly as if it was connected to an amp, and the mic preamp on the other side of the box will react as if a mic was connected. Without this the tone would be wimpy.
Level change - An electric guitar outputs a signal that is relatively low level but significantly higher than the average microphone. The DI box steps the signal down from instrument to mic level.
Unbalanced to balanced connection - Changing the unbalanced guitar signal to balanced mic level allows much longer cable lengths without signal loss or noise.
Pass through - The instrument signal is split and can be continued to an amplifier.
The Hi-Z/instrument input on your audio interface preamps do most of these functions well but a high quality DI box tends to work a bit better and allows you to split the signal to continue to pedals and amplifier.
DI Box options
There are a wide variety of DI boxes on the market today in passive, active, multi-channel, and vacuum tube designs. You can browse our DI box category here: DI Boxes & Re-amps.
A passive DI is just a transformer with a few jacks connected, it doesn't require any power. The Radial JDI is a very popular professional Passive DI Box.
An active DI is a more complex design that requires phantom power (supplied by the mic preamp).
The Radial J48 is a very popular professional Active DI Box.
Different designs, same price. Both proven professional tools used in studios worldwide.
Generally speaking, they both do the same job well. In specific uses or if you are looking for less transparency, one may type may be better than other.
There are also many designed specifically for bass recording with tone controls and overdrive or amp simulation circuitry.
The Radial Bassbone is an exceptional Bass DI/Preamp.
Bass doesn't always get the attention it deserves in a recording situation. I see a lot of home recordists rush through bass recording, only to later be frustrated with the bass when it comes time for mixing. It's really too bad because it's the foundation of the song. A great bass will groove tight with the drums and support the guitars. Fitting it in the mix will take minimal effort and you will be loving life.
A great recording starts with a great source. When it comes to tracking bass guitar, the source is comprised of many factors:
Musician:
Technique and playing position - Playing with a pick or with fingers or thumb. Intensity, Playing close to the bridge, in the middle or close to the neck. Choose what is appropriate for the song
What is played - playing bass lines that serve the song and don't clash with the drums or guitars rhythmically or melodically.
Tuning - Check the tuning often
Bass:
Strings - new strings usually sound best and give you the brightest tone to start with.
Electronics (Pickups and EQ) - The pickup selection and tone settings
Wood and construction - The wood used in the neck and body really effect the sound. Maple and Ash are bright and punchy, mahogany is thicker and darker.
Amplification chain:
Cable - debatable how much impact this has, how about just using one that doesn't hum or crackle if you move it.
Pedals - If a particular pedal helps get you the desired tone, go for it. I would hold off on spatial effects (delay, reverb) until mixing as they require their own attention.
Amplifier and EQ settings - tube or solid state. As a starting point put all EQ knobs at 6.
Cabinet - 1x12", 4x10", 1x15"
Cabinet position - where in the room, close to walls, on the floor or elevated
Everything contributes to the sound you'll be recording, do whatever you can to get this close to what you need from the start. It won't be the same for every song so you may want to have a few options for basses, though a Fender Jazz bass or MusicMan is versatile enough to get you what you need 80% of the time. Rent or borrow what you don't own before looking for magical plugins to solve all your bass problems.
In my experience getting good bass gear for recording made my life so much easier further along in my projects. For recording you don't necessarily need a massive bass rig, I use a Sterling Ray 34 (Low-end Music Man. Swamp ash body, maple neck, humbucker pickup with active EQ) into a small Ampeg BX112 solid state combo amp with a single 12" woofer. Greatest bass recording gear ever? Ha, far from it, but it got me so much closer to the sound I was looking for. Prior to that I was fighting with a mahogany bass that was deep but had almost no midrange when recorded making it hard to hear clearly in the mix.
A great bass tone in the room is more likely to inspire a great performance. Now you need to capture and enhance it.
The Recording Chain:
Mic selection - Dynamic mics and large diaphragm condensers are most common for bass amps. Spend some time comparing.
Mic position - distance and angle play a big part as always.
Direct Box (DI) - A direct box allows you to split the signal from the bass, one side continues to the amp, the other goes to a preamp.
Microphone Preamp - Every preamp has its own tone. A pad option may be required.
Compressor - Optional but worth testing if you have the option. Its very common to compress the DI track while recording in pro studios.
Record at a conservative level, if you're really digging in for a grindy tone keep the peaks no higher than -6dBFS (DAW metering). An average of anywhere from -18dB to -12dB is all you need. Dynamics will likely be reduced and additional processing is inevitable by the final mix. A clipped signal is useless.
Can you get a great bass recording with just a DI (or plugging right into the interface)? Yes. Can you get a great bass recording with just an amp? Yes. Splitting the signal with a DI before the amp and recording to two tracks gives you more flexibility when it comes to mixing. You may prefer the sound of one over the other, or a blend of the two.
When you do blend the DI and miked amp signals in your DAW it is very likely that you will hear some phase issues. The problem is caused by the DI signal gets to the interface before the mic signal does causing a slight delay. Try inverting the polarity of one of the tracks. This will usually be a dramatic improvement in the low frequencies. This can further be improved by delaying the DI track, often just by a few milliseconds or even samples. You might find it easiest to start with the tracks 'out of phase' then adjust the delay until you have the most cancelation, and invert the polarity again (now in phase). You may not get it to be absolutely perfect but do try to find the best compromise.
By now you should have a good, very usable, better than average bass track recorded into your DAW. We won't get into processing and mixing bass in this article, if you really need info on that right now, check out the Sept 2011 issue of Sound On Sound, great tips on mixing bass in there.
Have a listen to the audio examples I've prepared. Compare the different playing styles, mic position, mic type. In the delay compensation file, notice how the tone changes quite dramatically just by delaying the DI in increments of 10 samples.
