The key to a good bass track starts off with two critical components – a reasonable quality instrument and good skill of the instrument. Once you know you have those two ready, you can begin with the next critical choice when it comes to bass recording; do you go amp to mic or DI?
For those of you unfamiliar with the term, DI – also known as direct input or direct injection – is a means of recording bass directly to a mixer or DAW just like you would with vocals. While guitarists almost always prefer recording off a miked amplifier due to the specific tonal and natural colorations added by the signature sound of the amplifier, bassists and recording engineers are a little more split on the subject of bass DI, although most tend to do a mix of both and by no means avoid it (like guitarists). This added coloration of tone is due to the fact that guitar and bass amplifiers do not have a flat frequency response, meaning that there will be peaks and dips at certain frequencies in an un-uniform way. It is this non-flat response that gives many of the natural sounding characteristics that DI just won’t give you but unlike guitars, there are many more benefits to working with a bass through DI.
In a live stage or recording setting, playing a bass through DI is by far the best way for a clean, unadulterated sound that is perfect to work with in a digital editing environment that responds really well to compression and EQ. As long as the instrument and playing quality is up to snuff, DI is by far the easiest way to get the true sound of the instrument being recorded without having to deal with any added tonal changes and variations added by an amplifier – simply clean and consistent! But with that said, there are those that simply like to keep things old school, and if that’s your preference, more power to you, just be willing to deal with the consequences.
If you happen to own a bass with an active pickup system (if they need batteries, the answer is yes), you should be able to already directly plug in your instrument for recording or with use through a PA but if you’re rocking passive pickups, you will need the help of a DI box. The reason for this is because the raw signal given off by a passive instrument is far too weak in voltage for it to be clearly picked up by the PA or mixers (which are made to work with stronger signals). Connecting the passive instrument without a DI box will only cause impedance mismatch.
Think of the DI box kind of like a translator that takes your passive low-level line signal and makes it compatible with the microphone-level signal used by mixers, PA’s and DAW interfaces. If you are going to take this route, it is suggested that you buy a DI box with an input impedance of at least 500k ohms, although higher than 1M ohms is preferred.
Also, you have the choice of buying an active DI box which needs electricity from a mixer’s phantom power to operate or a passive transformer-based DI box which relies on the transformer for impedance matching without the need of external power. While pretty much all active DI boxes will give you the right amount of ohms needed, a small variety of passive boxes might not (at least not the recommended ohms of 1M), so just keep that in mind.
Mic That Sucker
As mentioned above, while DI is by far the easier of the two routes, there are certain instances where having that natural but uneven sound of a bass amplifier will far outweigh the need for something clean, easy and consistent. Also, there are simply purists out there who swear by old techniques. While there is no wrong choice to deciding between DI or a mic as it is basically a question of personal preference, choosing the mic route will require a bit more manual recording knowledge, equipment and a work area that allows you to turn up your speaker volume pretty loud. With that said, the first thing that needs to be taken care of is finding a proper microphone.
Most vocal mics come with a deliberate low-end cutoff to compensate for the proximity affect while recording vocals, meaning that unless you have that mic directly touching the grill of you bass amp, you will need to find a mic that is better suited for the bass if you want to retain enough power on that low-end frequency. There are plenty of mics out there that work great for this scenario such as the Heil PR40 and the Shure Beta 52, but any mic with a good low-end response will do you good.
Another route is to use either a non-vocal dynamic mic that has a reasonably flat low-end or a dedicated bass/kick drum mic and placing it about 6 to 12 inches from the most direct sounding speaker in your cabinet, although you might have to adjust it a bit to see what sounds best. Also, you can create a certain amount of tonal changes in your sound by simply moving the microphone to different positions around the speaker. While moving the receiving end of the mic directly at the center of a speaker will give you brighter tones, you can also move it a bit more to the side to attain warmer, more subtle sounds.
It is a good idea to experiment with different mic positions and distances until you find one that sounds best while leaving the EQ-ing for problem fixing until the very end (since you never know how a standalone recording will sound as part of the entire mix).
A Little Bit of Both
And finally, there is no rule out there saying that you can’t take these two techniques and mix them together, even while recording the same bass track. In fact, this is the premiere choice for several professionals. You can even use a small amp if you want to as the DI box will take care of the entire bottom end you need!