Handy Recording Tips & Techniques
A useful selection of technical information and tricks of the trade — a masterclass in miniature!
This new regular feature offers a feast of easily-digested recording tips and techniques designed to help you get the best results in your studio.
Just how do you get that frantic, chopped-up guitar sound that crops up on rave records?
There has been a recent upsurge of interest in the creative use of noise gates, due in no small part to revelations in the press that a significant part of the Shamen's 'sound' comes, typically, from using a hi-hat to rhythmically chop up guitar and other parts using a triggered noise gate. We at RM have had several requests for information on how to do this, and the technique is really very simple, the proviso being that your noise gate is equipped with a side chain access (or key input) socket. This allows the gate to be opened and closed under the control of an external signal input rather than by the main input, the classic use for this technique being to tighten up a sloppy bass part by using the bass drum to open the gate. In this example, taking a feed from the kick drum into the side chain of the gate will cause the gate to open only when signal from the kick drum is present. Consequently, the bass guitar, which is fed into the normal input of the gate, is only allowed through when the bass drum is present, giving the illusion of very tight playing.
The technique required to get the Shamen effect is pretty much the same: a programmed hi-hat (or other short percussive sound) part from a drum machine is fed into the side chain input of the gate while the part to be triggered (strummed guitars, sustained pad chords or what have you) is patched into the main input of the noise gate. What comes out is the guitar sound chopped up into short bursts that mirror the hi-hat pattern. The diagram shows how this is arranged. It will be necessary to adjust the gate's threshold so that it triggers cleanly from the hi-hat signal, and the attack time should be set as fast as possible. Experiment with the release control to vary the length of the bursts of guitar. Once you've mastered this technique, you'll be surprised at just how creative it can be.
What are VU and PPM meters, and why do they give different readings?
You may wonder why some equipment is fitted with old-fashioned, moving-coil VU meters, where a mechanical needle works in front of a dial, while others use the apparently more modern LED ladder system, sometimes referred to as PPMs. You may also wonder why both types seem to give quite different readings when presented with the same signal!
Mechanical meters were invented long before anyone had even thought about LEDs (Light Emitting Diodes), and being mechanical, there is a limit to how fast they can respond, as it takes a finite time for the needle to move from one end of the scale to the other. This might seem to be a disadvantage, as signals which are high in level but very short in duration are bound to produce an inaccurate reading. Take the example of a handclap; the meter will respond to the sound, but before it's got halfway across the scale, the sound is over and the meter starts to drop back again, never having reached the true, peak level. However, this apparent shortcoming can be turned to our advantage because the human hearing system works in a very similar way — we perceive sounds as being louder if they last longer, while a brief burst of the same sound will appear to be significantly quieter. By matching the mechanical properties of the meter to the response time of the human ear, the meter shows apparent loudness or volume rather than the peak level. This type of meter is known as a VU meter, VU standing for Volume Units.
Unfortunately, electronic processors and tape machines have no such hearing mechanism; overdrive them and the result is distortion, no matter how brief or how long the period of overload. If you rely entirely on VU meters when recording percussive sounds such as drums, you could be overloading the tape recorder to the point of introducing distortion, even though the meter is telling you everything is within limits. An experienced user soon gets used to this and allows for it when setting recording levels, but for the inexperienced user, the so-called PPM meter can be easier to use.
The PPM or Peak Programme Meter utilises a ladder of LEDs or a fluorescent bar-graph display which is fast enough to measure the true signal peak, regardless of how brief it might be. Because the peak may come and go so quickly that your eye may not be able to follow it, most such meters are designed to hold the peak value for a second or so to give you a chance to see it. The advantage is obvious, in that recording levels can be set up much more accurately, but VU meters still have the advantage that they tell you more about how loud something actually sounds.
Some meters combine the best of both worlds by using moving coil meters augmented by a single LED which lights up when the peak signal reaches the 0VU level. It can be quite instructive to compare the meter reading with the peak LED reading for different signal sources. With a steady tone, the peak and VU levels will be the same and the red peak LED should come on just as the VU meter needle reaches the 0VU mark on the scale. However, try the same thing with drums and you might see the peak LED flashing while the meter never gets past the -10VU mark!
Ultimately, you must also use your ears, as conventional, analogue tape machines don't suddenly go into distortion at 0VU but instead, the distortion gets progressively worse the more you overload the tape. On some sounds this distortion can be quite pleasant — used in moderation — and in the case of drum sounds, you can probably tolerate far more distortion than you could on vocals before it becomes objectionable. The trick is to experiment to find the maximum recording level for different types of sound and then make a note of the meter readings you expect.
What can I do if my timecode drops out?
If you're halfway through a session and you suddenly start getting problems with your time code, don't panic yet — there are a few things to try first. The first thing to do is clean your tape heads, as you could have a build-up of oxide causing the signal to drop out; if this doesn't work, try adjusting the playback level of the code, as some systems are very fussy if the level is too high or too low.
So far, I've suggested what many people would do instinctively, but a less well-known dodge is to use your compressor to recover the signal. I discovered this purely out of desperation, and though I can't promise success in all cases, it's certainly worked for me on several occasions where all other attempts at recovery have failed. The secret is to feed the time code track through the compressor on its way back to the Sync In socket on your sync unit or sequencer. Set the fastest attack and release time your compressor has to offer, pick a high ratio of around 10:1 and set the threshold to give a gain reduction reading of between 10 and 20dB. If you're in luck, everything will work straight away, but you may need to experiment with the compressor output level and the threshold settings. If it still doesn't work — now panic!
My drum machine sounds too clinical. What can I do to make it sound more like a real kit?
Modern drum machines provide incredibly good drum sounds, but they still don't sound quite like a real drum kit. One of the reasons is that sampled drums don't interact — when you trigger the bass drum, for example, the toms and snare don't resonate and there are no rattles. It seems ironic that when we're working with real drums, we spend most of our time trying to damp out rings and rattles, but when they're completely eliminated, as in the case of a drum machine, we start to miss them. For those of you sufficiently concerned about this to want to experiment, here's something to check out that really works.
To try this technique, you'll need a small guitar or keyboard combo and a snare drum. The idea is to use a split lead and feed some of the drum machine's snare drum output (or the whole lot if you don't have separate outputs!) to the combo amp, which should be set up lying on its back with the speaker facing upwards. The snare drum is placed, snare side up, on top of the combo's speaker and a mic positioned over the top of it to pick up the snare rattles. By adjusting the combo volume with the drum machine playing, you should be able to coax just the right amount of rattle out of the snare drum and then you can use your own judgement when deciding how much to add back into the mix. You may be surprised what a difference even a little sympathetic rattle adds. The accompanying diagram shows how this is arranged in practice.
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