Sound Effects Sources

At one time there were basically three ways of obtaining sound effects: (1) by actually creating the wanted noise, where this is feasible, in a studio; (2) recording on tape the effect and replaying it when needed (this was, and often still is, almost the only way of obtaining some effects); (3) using commercially available sound effects gramophone discs. The accurate ‘cueing-in’ of the last requires great skill.

In recent years, while all the above are still often important, the range of sources has extended. To add to the list, we have the following.

Compact Discs (CDs)

A wide variety of sound effects exists now on CD. Professional CD players can be set up to give very accurate, i.e. almost instantaneous, cueing of effects. If music is regarded as a form of sound effect then it should be noted that the CD is steadily replacing vinyl discs for music. Consequently (copyright problems having been solved) the use of music and/or effects in any programme will almost certainly need CDs.

Cassettes

Although we have made the point (page 132) that cassettes are generally inferior to reel-to-reel machines it is nevertheless true that modern cassette tapes, especially with a good noise reduction system, can be capable of more than adequate quality. Thus, this medium should not be ignored when considering replay systems. Small machines of high quality can be used for location recording of effects. Most are equipped with a noise reduction system. While cueing-up for replay is not as easy as with full-size tape, satisfactory results can often be obtained. The main drawback with cassette systems is that editing is virtually impossible, except by dubbing.

Cartridge machines

A cartridge machine (‘cart’ for short) is in some ways a specialised cassette system. Instead of the familiar compact cassette the cartridge is rather larger and contains an endless loop of tape running at, usually, 7½in/s (19 cm/s). It is possible to have up to about 10 minutes of playing time, although for jingles etc. much shorter tape durations are common: 30 seconds to a minute or so. The tape is drawn from the centre of the spool and returned to the outside, so that there is constant slipping between adjacent turns. This calls for specially lubricated tape.

The important feature of a ‘cart’ machine is that tone bursts can be laid to give an automatic cueing system, so that, for instance, at the end of the required effects sequence the tape is moved on to the start of the effect ready for another replay. (This is why relatively short tape durations are common. Spooling-on is relatively rapid.) With some cartridge machines more than one type of tone burst can be recorded to give tertiary cueing of other devices.

Digital machines using 3.5″ computer disks with similar facilities are now common.

A modern cartridge machine

Typical performance specifications

1. CD player for effects reproduction (‘cartridge CD’) Display shows track number and remaining time.

Frequency response: 20–20 kHz±0.5dB.

Signal-to-noise ratio: 92 dB.

Start time on average: 200 ms.

2. Cassette machine (professional)

Frequency response: 30 Hz to 20 kHz (+2, −3dB).

Signal-to-noise ratio, with Dolby C: 70 dB (weighted).

Start time: almost instantaneous.

Wow and flutter: ±0.1%.

3. Cartridge machine

Frequency response; 40 Hz to 16 kHz, +1.0, −1.5 dB.

Wow and flutter: less than 0.6% weighted.

Speed accuracy: better than 0.1%.

Start and stop time: less than 40 ms.

Cue system:

1 kHz primary (automatic).

150 Hz secondary, user selectable.

8 kHz tertiary, user selectable.