The sonic qualities of analog tape

One of the most important factors in the recording of characteristically warm sound is magnetic tape. Tape is rarely used as a recording medium these days and yet it has been one of the technical main stays within the music and recording industries for decades. Tape was used as a recording medium and of course in compact form as a consumer distribution medium.

How magnetic tape works

Tape passes over a recording head driven by mechanical reels, the recording head creates varying magnetic fields which are imparted to the ferric oxide particles which are bonded to a mylar backing material. This magnetic flux is stored on the tape by changing the magnetic orientation of the metal particles. The tape speed (espressed in inches per second or IPS) affects the recorded quality and as a general rule the faster the tape is rolling the better the recording. This is especially noticeable in the high frequency clarity and noise performance.

Why tape sounds good

Magnetic tape has a special characteristic in that it saturates gently when a high signal level is recorded onto it. As the tape distorts, gently and progressively beyond the recording level of 0Vu, it would be able to impart a character which no other recording medium could. A gentle, complex and very unique compression character is applied which tends to result in a fatter, rounder sound. Tape is able to gently enhance and round the low bass frequencies and often produce a slight enhancement of the lower mid range. This is coupled with a natural roll off of the extreme high frequencies which would overall produce a sound quality that many people describe as being warm.  

To a degree this warmth could also be attributed to the vinyl distribution medium which was prevalent at the time when tape was at it’s pinnacle. Vinyl is also favoured by some people because they feel the music sounds more natural and does not suffer the over compression/limiting and excessive high frequency boosts that some modern music suffers on digital release media.

Owning a tape machine

These days owning a high quality analogue tape machine can be a costly pursuit, tape in itself is more difficult to obtain and is now manufactured by only a few niche companies. The maintenance costs of an aging, high end tape machine should also be considerable. Again this type of skilled maintenance work is often costly and only carried out by a few small companies. Another issue with tape is it’s relatively high noise floor. Some musicians may feel that the added noise (without noise reduction) is not acceptable despite the subjective sonic advantages of the analogue tape sound. Like most audio processes sometimes the sound of tape may enhance a project greatly or detract from the sonic goals, it very much depends on the end users perception of what sound they prefer.

Faux tape effect

There are now numerous plug ins which seek to emulate the audio qualities of tape machines and they seem to be getting better and better. So you can approach the sound qualities of the best tape machines but without the high expense involved in maintaining a real machine. I suggest downloading a few demos and listening to the results and seeing if the tape emulated sound suits your music and mix style. Usually there are 2 types, one that seeks to emulate the multitrack tape sound and that of a 2 track stereo tape machine.

Tape is rarely a magic bullet, it definitely has sonic qualities that can enhance a project but I suggest that it should be worked with as a chain of sonic decisions as opposed to being bolted on to the end of a mix. This way you can work your mix into the tape and come up with a superior result. It will sound better if you sculpt the mix to suit the medium itself. This way the sound character is less of an extreme change and a more natural and organic part of the overall mix sources and it is much more likely to work in your favour.

Barry Gardner operates SafeandSound Mastering, a low cost high end cd mastering studio based in London, UK.