Bass guitar recording and mixing is highly understated. A good bass guitar track can make or break your song, as its the backbone to your song. So here are some tips that I (CJ Jacobson) have learned over the years.
Bass guitars either have an active pick up or a passive pick up. If your bass has active pick ups, then you can usually plug directly into the input of your sound card/interface. If your bass has passive pick ups (the most common), you need to have some sort of DI box or an external amp simulator, like a bass pod. These DI boxes take the low level signal of your bass and raise it to a line level. If your sound card/interface has mic pre-amps, you can use that as your DI box.
If you record direct, without the use of an external amp simulator, you will need to edit the sound with a bass amp simulator, compression, EQ, and maybe a bass chorus, to make it sound warm, full and alive.
The best and most consistent results come from close mic’ing a bass amp cabinet that is just off center a tad bit. You can and should also add a 2nd mic and set it about 4 feet back. Good mic’s to use are the AKG 414 and a senheiser 421.
Compression is needed for bass guitars because each string produces different dynamics and the dynamic range can get pretty big. Compression is used to smooth out that dynamic range so the bass track has that sonic backbone most songs desire.
To tighten up the low-end, set the ratio to 2:1 to 4:1, with an attack between 5ms to 20ms and a release between 120 and 250ms and a threshold between -5 and -10dB. Set the output to make up for the gain that was reduced.
Valve amplifiers are known for some of the best bass sounds and these can get expensive for a home studio budget. So adding a Tape simulator or some slight distortion from an amp sim is a great idea. There are also valve DI boxes and using one of those is a great tool for beefing up your bass sound without totally distorting it.
Combining DI and Mic Recording:
This is by far the best way, cause you have the option to use blend both signals into one huge one. The only worry is that the phase may be off between the DI and the mic’ed bass. So you may need to reverse the phase on one of the sound sources.
The fundamental bass frequencies are between 125 to 400Hz and boosting these can bring out more of the bass lines in the mix.
The harmonics for the bass are from 1.5 to 3kHz. Boosting these frequencies will increase the clarity and pluck.
Boosting between 5 to 7kHz will increase the finger sound.
Cutting between 40 and 50Hz will reduce the boom.
Playing with a pick can add harmonics up to 4kHz and will make the bass sound brighter. Playing with your fingers will produce a more mellow sound
Remember to never boost or cut the same frequencies for the bass guitar and kick drum. If you boost the bass guitar at 100Hz, 250Hz and 3kHz, do not boost the kick drum in those same frequency ranges. If anything, you should cut those same frequency ranges.