Many readers' cassettes that we receive are of a high standard of production, but others leave much room for improvement.

It is often the vocal sound that stands out as being the most problematic, and so this month we examine a variety of possible improvements.

Usually, producing a decent sound has less to do with the equipment you use, than with how creatively it is used. Obviously, that's not to say that equipment has no bearing on the matter. It must be of a certain standard, but given that, different engineers will produce differing results when working with the same tools.

Essentials

Aside from basic recording materials, a suitable microphone will obviously be necessary. It need not be expensive, but a very cheap mic is likely to sound nasal or boxy, and it is probably advisable to own at least one reasonable vocal mic. For the home user, this will usually means a dynamic mic with a cardioid response. You cannot really expect good results from any microphone that costs less than £30, and when choosing one, try to pick one that you've used before, or else persuade the retailer to exchange it if indeed it is discovered to be unsuitable. Certainly it will be useless to decide on your potential purchase by plugging it into a guitar combo and shouting 'One-Two' a couple of times. Remember too that a mic with a windshield is less likely to give popping problems than one without, and that the manufacturers' recommendations regarding the suitability of microphones for specific applications are in most cases not far from the truth.

By choosing reputable manufacturers such as Shure, Beyer, Sennheiser or AKG, you will not go far wrong, but when using them, remember to sing just over or under the mic and a reasonable distance away to avoid popping.

Having bought your microphone, the next question is to consider how exactly to process the sound. Most engineers are of the opinion that some kind of compressor and a reverb unit are essential if you want professional results. As most home recordists tend to put digital delays high on their list of priorities, these can also be put to good use.

Compression

Compression is essential unless you are lucky enough to be recording a vocalist with perfect mic technique, whose vocals stay at a constant level. At least compression goes some of the way to simulating the ideal singer by reducing the difference in level between the loudest and the softest notes. It may also be applied at either the recording or the mixing stage. However, if you are using compression while mixing, it is worth bearing in mind that every dB of compression is a dB of deterioration in the signal to noise ratio, so unless you are also using noise reduction, it is a good idea to use as little compression as possible.

Reverberation

Good results on vocals can be produced even by a cheap spring reverb, so there should be few problems here.

Artificial reverb was probably the first ever psychoacoustic sound treatment, as it gives our brains information about the physical qualities of a non-existent acoustic environment, and this effect can be further enhanced by the use of a digital delay unit that delays the reverb by a few milliseconds. The effect of this is to simulate the time delay between the original sound and the return of the first echoes from the nearest walls. If you assume that sound travels about a foot each millisecond, you can then work out how large you'd like your imaginary room to be. It is also interesting to delay the reverb on one side of the stereo, but not on the other.

When applying reverb, though, the secret is to use it sparingly, or else our brains will realise that they are being tricked - especially with budget spring reverb units.

Reverse Reverb

If used in moderation, reverse reverb can create an eerie effect, when the reverb actually occurs before the sound itself. Reverse reverb occurs nowhere in nature, nor can it be manufactured electronically as the circuitry needed would have to be able to predict the future. Therefore trickery must be used. The only way of producing this effect live is to use backing tapes, but with multitrack recording it is easy.

Having recorded, for example, a lead vocal track dry, you can simply turn over the tape or cassette so that it plays backwards and then record the reverb signal on to a spare track. When the tape is next played forwards, the reverb will then be heard before the words. It is easy, though to record over a track you wish to keep if you forget that the track numbering is reversed when the tape is played backwards.

At mixdown, an interesting effect can be produced if you pan the voice to one side and the pre-reverb to another.

Double Tracking

This is a very effective method of thickening a weak vocal track and is simply achieved by singing the same part twice on to two different tracks and then combining the two at mixdown. To do this, however, the singer is required to sing the two parts with exactly the same phrasing and inflections, and experience will show that some singers are able to do this naturally, whereas others may find it impossible.

In the latter case, it is still possible to achieve automatic double tracking (or ADT) by using a delay line to generate a single short delay of between 20 and 50 milliseconds which, though barely perceptible as a delay, has the effect of thickening the sound. Once again, artificial stereo depth can be created by panning the voice to one side and the delay to the other.

Delay

Repeat echo effects can be produced by digital, analogue or tape delays, and it can often be very effective to adjust the repeat speed to the tempo of the song.

In my studio, clients often ask for echo to be applied to certain words only, usually at the end of lines, and the way to do this is to turn up the effect send control immediately before the desired word appears, and down again directly afterwards. If the echo send is set and the echo return faded, the effect will not sound so clean, because it will include the echoes of previous words.

If, of course, you are fortunate enough to own a delay unit with a trigger facility (such as the Boss DE200), the echoes can be synchronised to a drum machine by means of its trigger output so that you could create rhythmically related echoes.

Summary

One article can only really scratch the surface of vocal processing techniques but I hope that it has given you food for thought. In future issues we will look at these and other signal processing ideas in greater depth.

For further information on vocal mic technique, refer to the 'Using Microphones' series in HSR April and May 84.