Recording music and sound
Recording music and sound

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Recording music and sound

3.1 Magnetic tape recorders

Figure 10 TS45 receiver; a wall-mounted system comprising of reel-to-reel tape, receiver and pair of speakers, 1964 (aluminium, plastic, tape), Rams, Dieter (b.1932)

Experiments showed that the use of paper tape coated with iron oxide particles significantly improved the signal-to-noise ratio. A plastic-based version of this magnetic tape, developed by the German company BASF, led to the development of a commercial tape recorder with audio characteristics that could nearly match those of the gramophone record, but not at an economical price. Secret work on tape recorders was undertaken by the Germans throughout the Second World War.

Soon tape recorders were in use by the American radio networks for pre-recording their broadcasts, the entertainer Bing Crosby being one of the greatest proponents of the technology. Recording companies were also quick to embrace the benefits of tape – especially the ease with which mistakes could be edited and retakes inserted. Also the ability to record for longer periods (30 minutes or more) meant less need for recording sessions to be split into short takes. Early domestic recorders were used primarily for playing stereo recordings, but they were costly in terms of both the hardware and the media: a pre-recorded stereo tape cost five times that of the equivalent mono LP disc. The sales of pre-recorded tape plummeted once stereo LPs became available in 1958. From that point on, domestic tape recorders were used mainly by enthusiasts for home recording.

An important feature of the use of magnetic tape is the effect on the sound of the speed at which the tape travels. The audio bandwidth of a tape recorder is determined to an extent by the selection of the tape speed, i.e., the rate at which the tape is drawn across the record and play heads. The wavelength of the audio signal recorded onto the magnetic tape is proportional to the tape speed. As the tape speed is increased, a greater proportion of the tape is used to store the audio signal, allowing higher frequencies to be retained on the tape. Because high tape speeds are less economical on tape usage, tape recorders had speed controls to allow users to select the tape speed to suit the audio quality. The figures below give you some idea of the variation of tape speed that was used for different purposes.

Speeds are measured in cm/s (centimetres per second) and ips (inches per second).

Table 1 Tape speed, bandwidth and their uses

Tape speedBandwidth Use
38 cm/s (15 ips) 20 Hz-20 kHzstudio recording
19 cm/s (7½ ips)30 Hz-15 kHzhigh-quality home recording
9.5 cm/s (3¼ ips)40 Hz-13 kHzgeneral domestic music and speech
4.8 cm/s (1 7/8 ips)50 Hz-6kHzrecording speech (dictation)
A232_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371