Recording to a computer can make it easier than ever before to produce a great vocal sound but there are also pitfalls to watch out for...
One of the most common questions we are asked here at SOS is still "how can I achieve that 'produced' vocal sound?" Now that so many of you are recording directly to computers rather than to tape or dedicated digital multitracks, I thought it might be an idea to explore vocal recording in the context of a typical computer-based studio.
The first issue with a computer system is how to get a mic signal into it. Typical soundcards have only line inputs, or, if they have mic inputs at all they're often designed for use with consumer-quality microphones. Thus, you're always going to need either a mixing console or a separate mic preamp to interface studio-quality mics.
If you're using a mixer, it is a good idea to establish as short a signal path as possible. This entails using the mixer's channel direct outs, if fitted, or even taking the signal feed from the channel insert send. You can also feed signal out of the mixer via an unused pre-fade aux send, which is an effective way of using a simple 'something-into-two' stereo mixer for simultaneous monitoring and recording. In general, the more unnecessary circuitry you bypass, the cleaner the signal will be.
As regular readers will no doubt be aware, a capacitor microphone will produce the best vocal results in the majority of situations. To use one of these you'll need a mixer or preamp with phantom-power capability, or possibly a separate phantom power supply box. A few of the better audio interfaces with built-in mic preamps have phantom powering, but if you plan to use one of these, make sure the full 48 Volts is supplied, as many capacitor mics either fail to work altogether or deliver a reduced level of performance on lower voltages.
Mic positioning for vocals is relatively simple. The main things to remember are to keep the mic away from walls and corners, and to hang up absorbent material against the walls if the room sounds too 'live'. Always use a pop shield between the mic and the singer, and work around nine inches from the mic. My vocal room doubles as a store room, and it seems that the more rubbish I accumulate in there, the better the acoustics get, presumably because the sound is scattered rather than bouncing back from unobscured flat walls. Avoid small square rooms with hard walls, as these can sound very boxy.
When you work largely or exclusively on a computer, signal processing tends to become something you do with plug-ins, but it's actually useful to compress vocals with a conventional outboard compressor at the analogue stage, before they enter the soundcard's input and pass through its converters. This makes the best use of the dynamic range of the converters. However, it's best to leave room to add more compression later with your plug-ins, by erring on the side of under-compression. To do this easily, set up the amount of compression on the outboard unit that seems right for the vocals, then adjust its compression threshold to produce around 3dB less gain reduction than that 'ideal' setting.
Normally I advocate leaving EQ until mixing, but there are some analogue equalisers that simply sound nicer than plug-ins, so you may want to apply some EQ on the way in. I use an SPL Channel One for all my computer recording, because it combines a clean mic preamp with a nice compressor and a good-sounding equaliser, which means that I can do all my processing in one place. Usually a little high-end 'air' EQ combined with low-cut filtering, is all that's needed. (If you do choose to use EQ on the way in, as with compression you should take care not to overdo it.)
I recently fitted a digital output card to the Channel One, which makes connecting to a computer very easy. If you're using a budget soundcard with less-than-great converters, a preamp with a digital output is a good way to get high-quality audio into the system, provided that the soundcard has the appropriate digital input.
Setting Up To Record
Depending on your choice of audio interface or soundcard, you may have enough separate outputs to enable you to set up a foldback mix using the pre-fade sends on your sequencer's virtual mixer. If you only have a stereo output, the singer will have to make do with hearing what you hear in the control room. In practice, I tend to send the singer the control-room mix anyway, as this can be rebalanced to their taste without affecting my ability to record them. Having a headphone amplifier within reach of the singer helps, though, as it's useful for them to be able to adjust their own 'phones level.Depending on the style of music you're producing, you may be able to get away with recording vocals at the opposite side of the room to the computer, to minimise fan noise, but ideally you'll want to put the vocalist in a different room altogether unless you have a very quiet computer. The recording room needn't have a soundproof door, as you don't need very much attenuation to cut out computer fan noise and in the absence of a talkback system, it's handy to be able to shout to the singer without having to open the door! In my situation, it's often enough to have the singer in the next room to the studio with the door open, provided that they're slightly around the corner, to take them out of the direct path of any computer noise passing through the door.
When recording in this way it's important to work with the control-room monitors turned down fairly low, otherwise they'll leak into the vocal mic. It's also a good idea to turn off any metronome beeps, as these have a habit of leaking from the headphones into the vocal mic.
Most singers perform better with a bit of vocal reverb in the foldback, but not all software packages allow you to monitor with plug-in effects. If you can, all well and good, but if not, you might have to resort to using a hardware effects box. Those using stereo-out soundcards have two alternatives: either add a little reverb to the whole stereo mix during recording, or pan all the vocals to one side of the soundcard output and all the backing track to the other, then add reverb only to the vocal output. It's really a matter of picking what the singer is happiest with, but when you don't have all the facilities of a big hardware mixer to help, you have to improvise. Of course, adding hardware effects to selected parts is not a problem if you have a multi-output soundcard and an external mixer.