Recording & Mixing Bass Guitar
Recording & Mixing Bass Guitar
Bass is the backbone of your music, and in many cases – particularly with more modern styles – the whole metaphorical house would collapse without it. Lou Reed once put the importance of bass across rather well. "I wouldn't want to hear Beethoven without beautiful bass, the cellos, the tuba. It's very important. Hip-hop has thunderous bass. And so does Beethoven. If you don't have the bass, it's like being amputated. It's like you have no legs."
Just like building a house, it's essential to build on solid foundations. When done correctly, your bass should work with the rest of the band to provide a punchy and tight solid backbone to your music. Unfortunately for the beginner, recording great bass can seem like a dark art, with many results sounding muddy or unbalanced. Thankfully, like most things, it's easy when you know how. In this article, we'll get you up and running with great results, fast.
(Pictured above - Shure PGA52 Kick/Bass mic)
It goes without saying that you need a great bass player to get professional results, but it's equally important to set up your instrument first. As described in our post about recording acoustic guitars, we highly recommend you invest in setting your instrument up properly before doing anything else. As an absolute minimum, you should check the instrument action, its intonation, and consider a string change. Finally, and most importantly, always tune the bass before and between takes.
Bass Recording Methods
There are 3 main methods for recording bass guitar: 1. Recording direct using a DI box, 2. Using a Microphone, 3. Using a combination of direct and microphone techniques.
The method you choose depends on a number of factors. Below we'll consider each option in more detail.
Should I DI My Bass Guitar?
Unlike electric guitars, it is common to use a DI to record bass. Although this technique delivers a good solid clean sound, it can also lack life. If you want to capture a more 'real' sound, there's nothing quite like micing up a bass cabinet. DI's, however, do have other distinct advantages.
- They offer a back-up, allowing you to re-amp the signal should you decide to later.
- When blended with a microphone signal, DI's can be used to help reinforce any frequencies not produced by the amp.
If you do decide for practical or budgetary reasons to use a DI on it's own, the result can be greatly improved by processing the signal using amp simulation software. Amplifier and Cabinet modelling software has come in leaps and bounds over recent years, to the point where even the stock options with programs like Garage band can reproduce very convincing results.
(Pictured above - Radial PRO DI with Monster Cable)
Recording Bass with a Microphone
For those that have the luxury of a great sounding bass amplifier, the best and most characterful results can be achieved using a microphone. The most important factors when choosing a mic for bass guitar are: (a) frequency response and (b) how well the mic handles high sound pressure levels (SPL). (a) It is desirable to have a frequency response shaped specifically for bass instruments, meaning it has a strong low-frequency response, with a scooped mid and a presence peak around 3-5KHz. (b) When it comes to high SPL levels, dynamic microphones will typically perform best; however, this does not rule out condenser mics entirely...
Can I Use a Condenser Mic on Bass?
As determined above, dynamic mics work great for bass guitars. On the flip-side, they also impart their own particular sound on the recording thanks to their strong, tailored frequency response. For those who prefer a more natural sound, it's worth considering a condenser mic; just make sure you keep the bass amp to a sensible level and consider using a pad if the signal is too hot. A pad can be enabled at the pre-amp or even at the mic if your model has this feature. Pads will typically allow you to attenuate the signal by 10 - 15dB.
There is no one size fits all solution here, so it's essential to experiment with position and distance. Listen carefully to determine what sounds best for your application.
First up, try experimenting with mic position relative to the speaker cone. Just like electric guitars, you can easily achieve a bright or warm tone depending on where you place the mic. As a general rule, positioning the mic toward the speaker cone edge will produce a warm tone while pointing it directly at the centre will give you more 'bite'.
Secondly, microphone distance from the grill will also affect the tone. All microphones are different, so listen carefully for changes using a pair of good quality headphones. As you move the mic further away from the grill, the tone changes from a very dry, focused and non-reverberant tone, to a more natural and ambient sound. The other consideration here is proximity effect, whereby the bass frequencies become more accentuated as a directional mic moves closer to the sound source. Engineers will often exploit the proximity effect to thicken up guitars, but you might find that bass guitars benefit from a little breathing room; somewhere between 4 - 18 inches will usually work depending on preference.
Often overlooked is the floor surface. For example, if you place the amp on a solid floor, the reflections will result in a brighter tone than that of an amp placed on a carpet. Keep in mind that the further your mic is from the amp, the more significant floor and room reflections become. Generally speaking, a microphone placed further away from the speaker grill will be more representative of the overall amp and room sound. In other words, it will sound more natural. Depending on the style of music you're recording, this may, or may not be desirable.
(Pictured above - Shure Beta52)
A little info on Polar Patterns
By far the most commonly used polar pattern for recording bass is cardioid. In short, their directional pickup allows for greater rejection of room reflections or other instrument sounds. On the other hand, they also colour the sound more - most notably through the proximity effect described above.
If you want to avoid the proximity effect and capture a more natural tone, consider using an omni-directional polar pattern. As we described in our Recording & Mixing Vocals article, omni directional microphones will produce a more 'natural' or 'open' sound, but they will also capture more reflections. If you have a great sounding room, some natural reverb can be desirable; however, for most home or project studios, it is far safer to tame room reflections and add reverb during mixdown.
Recording a Blend of DI and Microphone Signals
Many engineers will insist on using a combination of mic and DI techniques to record bass. A blend of the two allows you to get the best of both worlds. In fact, some engineers will even record up to 3 or 4 tracks for the bass, usually featuring 1 DI track and multiple mics. For example, you could use a specialised kick/bass dynamic mic up close alongside a condenser mic placed further away and then combine this with a DI signal. When mixed together, it can be possible to arrive at a more diverse range of sounds suitable for many styles of music - just make sure you check the phase relationships between these different channels. The key here is to be patient and don't be afraid to experiment. Different bass guitars, amps and the room itself all call for a different approach. The import thing is to trust your ears, and remember that if it sounds good, it is good.
In the vast majority of cases, getting a great mix starts with the relationship between your drum tracks and the bass. It's essential to get a good groove between the kick, snare and bass to build the foundations we talked about at the beginning of this article. Before you start any mixing, listen carefully to the groove and timing between the drums and bass. In many cases, the performance can benefit from a little tightening up. This process typically involves cutting, moving, and in some cases, time stretching some notes. Modern recording software has come a long way toward assisting or even automating this process; however, I find that some of this automation can remove the feel of your performance altogether. If you want to preserve the human element of your performance, try and keep editing to a minimum. Sometimes, the best way is to manually locate and edit the offending notes. If you find yourself having to make a lot of changes, it might be better to consider re-recording.
The key point to remember here is that something has to be the main reference point for timing. In the vast majority of cases, the reference point is almost certainly the drums. Listen carefully and assess the relationship between the kick, snare, and the bass; they should work very closely together to form the backbone of your track. If they don't, everything else you do after will be in vein.
Once you are happy with the final performance, you can begin considering how the bass sits within the overall context of your mix. The following are typical processes to consider:
Where you choose to boost or cut EQ on a bass guitar is essential to producing a controlled and clean low-end within the context of your overall mix. The best results are usually achieved by NOT boosting at the same frequency as your kick drum track. For example, if you applied a boost around 80Hz on the kick drum, try cutting a small amount from the bass at the same frequency and boost further up between 100 - 150Hz instead. It then also makes sense to cut the kick drum track at the boosted bass frequency. This approach will help to control and tighten up the low end.
Some bass tracks can benefit from a small high-frequency boost. If you decide to do this, listen carefully with a good set of reference headphones to determine which frequency gives it some presence or attack without clashing with other percussion tracks. Once again, it doesn't make sense to boost your kick drum attack at the same frequency as your bass; you need to give each track its individual space within the frequency spectrum.
Finally, if you haven't gathered already, making EQ decisions when the track is soloed is like stabbing in the dark. You need to hear the relationship between each instrument to make informed choices. Make sure you regularly reference your EQ settings against the drums and the entire mix.
Note: Check your Mix on Different Systems
With bass frequencies, it is particularly important to check your mix on a range of audio systems. A deep low-frequency bass guitar sound might sound great on a high-quality studio monitor system, but it could be completely inaudible on many consumer audio systems - particularly cheaper earphones. A bass sound with a good balance between low and low-mid frequencies will usually transfer better.
Also, remember that bass frequencies can determine the master fader volume as bass frequencies contain more energy than high frequencies. If you're having trouble getting the bass to sound audible in context with the entire track, try rolling off some low-end, which should then allow you to turn the whole track up without it peaking.
Compression is typically applied to bass as it helps to maintain consistency. How much you add will likely depend on how the track was recorded. For example, it is common to compress a DI bass track more heavily than one recorded with an amp and microphone. This is because the amplifier imposes a certain amount of natural compression - particularly if you have a valve/tube amp. Any amount of compression added should be enough to smooth out the performance and maintain a solid groove. Be careful not to set your attack too fast, or you will squash precious transients. Equally, make sure the attack is not so slow that it ruins the groove entirely. The release time will also need careful consideration to ensure you maintain dynamic range and groove. Set the release too low, and the compression will be released almost immediately after the signal drops below your threshold. Set this too high, and the compressor will be almost always compressing and could ruin the groove and strip the performance of any dynamic range. If your compressor has an auto attack and release function, you might want to consider using this if you don't feel confident. In any case, the attack and release settings will depend on playing style and the desired sound; trust your ears on this one.
Compression can be difficult to understand, and if you're new to the basic controls, it's well worth researching and fully understanding these before you apply anything. The video below goes a long way to explaining compression fundamentals for beginners – albeit from a drums perspective – but the controls and purpose remain valid.
Last but not least, too much reverb on the bottom end can really muddy up a mix. The trick here is to use short reverbs with a little pre-delay to separate the bass from the reverb sound. Any reverb should be just enough to help blend the track in without sounding overpowering. As described in our recording vocals article, you can help to avoid muddy sounding reverb and retain focus by applying a little EQ to the return signal of your reverb.
There are no right or wrongs in most recording applications; there are, however, guidelines that usually yield good results. By following the fundamentals in this guide, you should be well on your way to building a solid base for your track - pun wholeheartedly intended.
About the Author
About the Author
Marc forms part of our Pro Audio team at Shure UK and specialises in Digital Marketing. He also holds a BSc First Class Hons Degree in Music Technology. When not at work he enjoys playing the guitar, producing music, and dabbling in DIY (preferably with a good craft beer or two).