Prices and quality of plug-ins that simulate guitar amps just force you to record guitar at home, on your headphones, without disturbing anyone. We use the plug-in, and at the same time did not close the possibility to „the real thing” – recorded tracks can be easily processed in the recording studio with your choice of amplifiers, speakers and microphones, with any preamplifier. Time (and money) gained on working at home can be used in the studio, trying different amplifier settings and microphones. However, if you plan to re-amp your tracks, you have to record them well.
It is not as easy as it may appear. Guitarists often have a very good and expensive equipment, but when it comes to recording at home they are satisfied with just anything, and also willing to believe in all the urban legends. Bassists have a bass guitar, a cable and an amplifier – which at home is useless. It’s no wonder that even experienced sound engineers have problems with recording guitars direct – they are not guitarists and they don’t know what’s the problem at all, or they are guitarists and focus on irrelevant details, omitting important aspects. It is possible to record good bass or guitar tracks at home – perhaps this will require additional equipment, but it’s worth a try. It will be easier, if you want to use the simulation only, you’ll have to transmit a signal from the guitar to the computer only. However, if you are planning reamping with the real amp, you have to be able to transmit the guitar signal from the PC to an amplifier intact, which alone is not so simple, but in addition to this the signal must be clean, free from noise and distortion and within the strict level range, otherwise all the effort on recording and editing will be in vain.
A few obvious comments. First – the tuning. The sound of the guitar is based on the tuning. You cannot check it too often. Yes, we may have perfect pitch, but check tuning in every pause. The new TCs or Korgs, showing all the strings at once are nice, but a simple tuner is also OK. Badly tuned guitar tracks cannot be repaired in any way, even with Melodyne. I will not come back to this topic, just remember. A good set of strings and properly set instrument is obvious.
Second – hum. CRT fortunately disappeared from our desks, but there are the cell phones and wi-fi. Keep this in mind and minimize noises. Certainly do not record with the cell phone in your right pocket 😉 Guitarists usually know how to deal with a variety of noise and hum problems. Remember that the noise gate is no solution in this case – the track simply must be clean and free from noise. Basically, recording guitar at home does not create ground loop by itself (if the loop wasn’t there before, of course). To avoid ground loop, power all effects from batteries and not from AC adapters – perhaps a little more expensive but less hassle, and without hum from poorly filtered power supplies. Power supplies with more outputs are especially dangerous – in fact you get ground loop in the package, unless the unit is properly designed and thus very expensive. A cable is an important element , but the guitar players are well aware of it. Recording requires good cables, but they don’t need to have an outstanding quality, better than the stage ones. This is also related to the general condition of the guitar with a special focus on battery (in instruments with active electronics) – batteries must be new and good!
Let’s connect our guitar or bass to the recording system. Most modern interfaces usually have Hi-Z inputs with high input impedance, specifically designed for recording guitar. Of course, we can use it – at least for now, until we know more. Most guitarists buy interfaces just for recording guitars, so it can be assumed that such input is present. Also while mic preamps often have Hi-Z inputs, you have to remember that this is not the same as the line input – there is either a switch or another socket for it. But what if such a Hi-Z input is neither in the interface, nor in the preamp? Can your guitar or bass be connected to the line in input of the interface? It depends on bass and guitar, and whether we do it for real or just for fun. First of all, it is worth a try, we won’t break anything. Line input unfortunately has usually low input impedance, too low to make the instrument sound full. Low load impedance causes a decrease in the level and drop in the lowest frequencies. Guitar somehow can still sound well, but removing the bottom from the bass track will not work. Passive Precision does not work this way. Basses with active electronics are more forgiving – sometimes an active bass easily withstands the load of the line input, but you need to check it first.
Guitars with preamps and buffers are rather rare. Active pickups are more common, but unfortunately they are now designed to work with normal guitar pots and like passive pickups have high output impedance. Although they have rather high output level, under load they distort and sound bad. Is there no solution? There is, at least in theory. It looks like each guitarist has floor effects. If one of these effects is a device with an electronic bypass switch (e.g. Boss, Ibanez, Digitech, etc.), then we can use it as a buffer – it can be even chorus. Relax, we will not record all tracks with the chorus, it’s about the use of the follower these effects have on input – and record in bypass mode. As can be easily checked on the diagrams (Boss, Ibanez), there is the FET or bipolar follower at the input of such an effect, and the input impedance is about 500kΩ or more. Even in bypass mode, the signal passes through at least two followers, and the guitar is not loaded. This is the cheapest „buffer” for recording guitars and sometimes works surprisingly well (but sometimes not). The only problem for now is, that, unfortunately, listening closely, one can hear that these effects change the sound a bit even in bypass mode. It works somehow on stage, when connected to an amplifier, but in the studio or with the headphones one can hear that this is not the same sound. If you do not have Hi-Z input we can accept that – now. When we will examine that later, we will stop using floor effects as a buffer 😉
Bassists may want to use the head line out for recording. I think it’s not a good idea. Bass amplifier is used to amplify the instrument and works with a set of speakers. Line-out is usually equalized and has little in common with the real sound of the instrument. EQ is used to obtain the sound from the speaker, not on the line output, these are two different things. If your amplifier has a pre-EQ line out, it can be used with the correct set of levels, but we have to be very careful, because noise, hum and interference can be quite disturbing (500W amplifier on the stage is so loud that no one can hear any noise). And remember – the sound of Ampeg comes from the Ampeg speakers and not the line-out.
When it comes to recording bass guitar, I would like to emphasize one thing: never, ever use the equalizer in your active bass! All the knobs should be set to zero – flat – position. Any equalization is very difficult to „undo” and usually only makes the sound worse. Even when it seems that „a little more bass will not hurt” – no! Don’t do it. Another reason for not touching equalizer, especially trying to add bottom, is a real possibility of distortion. EQ powered by 9V battery will not transfer the undistorted signal from even mid-range passive pickups with the bottom boosted by a dozen or so decibels. The battery of course has to be new and of good quality, but it does not help. With the bass amp, on stage, it may work well – but not in the studio. Even if there is no distortion (because, for example, we have 18V electronics with two batteries, or/and we are adding „just a little bit”), the equalizer must be set flat. If we will have to EQ it, we will do that later. EQ in the bass breaks sound. Really. Well, IMO 😉
As you can see, apart from the input impedance I more and more often mention the signal levels. Yes, because it is big, if not even bigger problem. An audio interface is not a guitar amp and it cannot accept high levels without audible distortion and clipping. In addition, devices plugged in the signal path or active electronics in the guitar make it more difficult to manage – in the studio these effects and buffers show how much they are worth. Therefore, in your free time take a look at the other issue – the levels in the signal path – it’s about the vocals, but works with guitars too 😉