Paul White explains the APRS tape labelling system and offers a few hints of his own on tape care.
With the introduction of small‑format tapes such as DAT and Video 8 (as used in Tascam's DA88), there's a tendency to treat valuable recordings in rather too casual a fashion. The importance of correct tape storage tends to get overlooked, and judging by some of the DATs that come into my studio for editing or sweetening, labelling doesn't come far up the list of priorities either. Tackling the issue of labelling first (on the basis that you should always label a tape before storing it), there is a simple tape labelling system, devised by the APRS (Association of Professional Recording Studios), which has been introduced as an industry standard. This encompasses both multitrack and stereo master tapes, any copies or clones — and of course DAT. Colour coded labels are available from the APRS, but in the case of DAT tapes, many brands now come with a set of APRS colour coded labels included. Even if you don't have the 'official' labels, writing the correct description on the box will suffice.
It seems self‑evident that any tape should include details of the format, such as how many tracks there are, what speed they were recorded at, what noise reduction (if any) was used, and so on, but it still surprises me that tapes come in to my studio without any of this information. Analogue recordings should always include information on the tape speed, track format, noise reduction, and record EQ (NAB/IEC), as well as the titles, times and recording dates of the material on the tape.
Analogue, open‑reel tapes are usually stored 'tail out', to reduce 'print‑through' (where the magnetic information from one layer of tape is partially transferred to the layer of tape next to it, resulting in pre or post echoes). Tapes stored 'tail‑out' must be rewound before playing. If noise reduction is being used, print‑through is unlikely to be a problem, but it's still good form to adhere to this convention. Furthermore, before storing a tape, it should be wound back to the beginning, and then spooled through to the end (at normal speed rather than at fast wind), so that it 'packs' evenly on the reel. Some machines have a special spooling mode for this purpose, which is rather faster than real‑time.
Digital tapes, whether stereo DAT or multitrack (such as the Alesis ADAT or Tascam DA88) should display the recording's sample rate and the type of recording machine used. One of the worst crimes you can commit is to mix 48kHz and 44.1kHz sample rates on the same DAT tape, as this can create havoc if the tape is subsequently sent for digital editing. A quick tip — if you patch an Alesis AI‑1 digital interface between the DAT machine and the digital editing system, then set the destination sample rate for 44.1kHz, any 48kHz tracks will automatically be converted to 44.1kHz.
Both digital tapes and analogue cassettes perform better if they are wound through to the end and then back to the start before being used for the first time. This helps loosen up any binding of the tape in the cassette shell, and may reduce the number of record errors. It is also recommended that the first minute or so of a DAT tape should be recorded with silence before the recording proper starts. This is because the first few turns of the tape onto the take‑up hub may wind less than perfectly evenly, and this increases the risk of record errors, which, if serious, may even cause audible drop‑outs.
After a session using digital tape, it helps to wind the tape right through to the end, then fast wind it back to the start again before starting it. Print‑through is not a problem you have to worry about with digital tape.
Politically Correct Labelling
The following descriptions are condensed versions of the labelling conventions outlined in The Master Tape Book (see the 'More Information' side panel).
- Session Tape
Usually a multitrack tape (analogue or digital), this is the tape used to make the original recordings — the working tape onto which material is recorded and overdubbed. The Session tape may contain out‑takes as well as wanted material, and an album project may comprise several Session tapes. Where the recording has been made 'direct‑to‑stereo', the original recording is still known as the Session Tape. All relevant data as regards the tape format and the recorded contents should be recorded on the tape box or inlay card.
APRS label: blue with the words 'Session Tape'.
- Original Master
When a multitrack tape is first mixed to stereo, the result is the Original Master tape. This is usually not the tape used for final production; apart from the fact that it would be unwise to send the only master tape away for record or CD production, it is likely that the mixed material will need re‑ordering, the gaps between tracks will almost certainly need editing, and some form of further processing may be necessary, such as compression or EQ. APRS label: red with the words 'Original Master'. - Production Master
The Production Master is a copy of the wanted material from the Original Master tape or tapes, but with the track order and spacing the same as it will appear on the final record or CD. It is common for further EQ or overall compression to be added at this stage, and there may be fade‑outs and level changes to consider. If the Production Master includes material recorded at different times or in different studios, it may be necessary to equalise individual tracks to make the album sound more homogenous.
The type of release medium should also be recorded, as different master tapes will be required for record/cassette and CD production. For example, the tracks on a CD run continuously, whereas the tracks on a vinyl or cassette album are arranged as two sides. There is usually a gap of one or two minutes between sides on the Production Master tape. For cassette production, side one is usually made slightly longer than side two, so that when the tape is turned over at the end of side one, side two is ready to play.
For DAT tapes destined for CD release, a sampling rate of 44.1kHz is preferable, though any CD mastering house should be able to work from a 48kHz tape made on a semi‑pro DAT machine.
A full listing of the songs by title, start time (Start IDs) and playing time should accompany the Production Master, including full details of the recording format and the type and model of machine that was used. This latter point is important, because masters made on Teac or Casio DAT portables are pre‑emphasised during recording (pre‑emphasis is a type of top boost used during recording, which is reversed upon replay, providing a degree of noise reduction). If these tapes are simply copied in the digital domain without first being de‑emphasised, they will sound bright and thin.
APRS label: green with the words 'Production Master'.
- Production Master Copy/Clone
This allows distribution of the tape for manufacturing without having to release the original. A tape made by analogue copying is known as a copy, whereas a tape made by digitally transferring the data from one digital recorder to another is known as a clone. A clone should be identical to the original in all ways, while a copy will always undergo some slight degeneration.
APRS label: orange with the words 'Production Master Copy Clone'. The appropriate Copy or Clone check box should be ticked, and the information from the actual Production Master should be included.
- Safety Copy/Clone
A backup copy or clone of any another tape. All details from the original tape should be included.
APRS label: pink with the words 'Safety Copy Clone'. The appropriate Copy or Clone check box should be ticked.
- Not For Production
Any tape which must not be used as a source for media manufacture.
APRS label: yellow with the words 'Not For Production'.
- PQ‑Encoded Master Tape
The U‑Matic tape used in the manufacture of CD or other digital media. This tape includes coded data, enabling the CD player to find individual tracks, display the total number of tracks, the time remaining and so on. Currently, there is no way to perform this process at home (it requires the services of a CD mastering facility), though software is becoming available which will allow the home user to produce PQ‑coded Write‑Once CDs or CDRs, from which conventional CDs may then be manufactured en masse.
APRS label: grey with the words 'PQ‑Encoded Tape Master'. Check boxes are provided for the various release media formats and to indicate whether the tape is an original or a clone. In most cases, the release medium will be CD, and different U‑Matic masters are needed for Minidisk and DCC production.
- Media Version
Copy or clone made for radio broadcast, film/video soundtrack, or similar purpose. If the tape is recorded with timecode, details should be included on the label.
APRS label: yellow and marked 'Media Version'. Check boxes are provided for Radio, TV, Film or Video.
DAT Tapes
Because DAT tapes can't be recorded above their maximum level, it is usual for them to be recorded so that the maximum peak level falls around 2dB short of the maximum meter reading, so as to build in a small safety margin. Record between one and two minutes of silence onto the start of the tape, and if test tones are required (see separate 'Tones' side panel), a ‑14dB, 1kHz tone (14dB below the full‑scale meter reading) will suffice. The level should be noted on the label or accompanying paperwork. At the end of the recording, the machine should be allowed to run on in record mode for at least half a minute before the tape is stopped.
When recording DAT Production Masters, set the Auto ID function to On. However, Auto ID must sense the presence of the programme material before writing the ID, so there's a chance that the first fraction of a second of the track will be missed. To get around this, manually move all IDs back by half a second or so after recording.
Storage
It is well known that analogue tapes deteriorate in storage, and many master tapes over 10 years old are virtually unplayable, unless they are first 'baked' at a controlled temperature to drive off the moisture they've absorbed over the years. Even this cure is only temporary, and it is advisable that digital copies of all valuable old material are made as soon as possible. Of course, there's no guarantee that digital tape won't degenerate in the same way, but at least you can clone it onto a fresh tape every five years or so, and keep more than one copy of anything really important.
No tape will last forever, but storing it properly can make a huge difference to how long it does survive. The enemies of tape are magnetism, excess moisture and heat. Even short terms of exposure to an excess of any of these factors can cause irreversible damage. Tapes also need to be kept clean, so storage in a dust‑tight case is a good idea.
When I interviewed Toyah [see January 1994's SOS], I noticed that her husband Robert Fripp had put all his masters into chicken incubators to provide a stable environment. A splendid idea, but you don't need to go to such lengths with your own tapes, provided you apply a little common sense. First of all, magnetism — obviously you shouldn't leave valuable tapes piled on top of a speaker cabinet, but other sources of magnetic fields include computer monitors and mains cables, especially those carrying large currents. Store your tapes at least a couple of feet from any of these.
Most modern houses aren't excessively damp, but if you have a garage studio, store your tapes in the house rather than in the studio, and pick bedrooms rather than cellars, as these are less likely to be damp. If you do have to leave the tapes in the studio building, consider buying a dehumidifier to prevent moisture build‑up. This will also help protect your gear.
Tapes like to be stored at a constant temperature, and as far as the home recordist is concerned, the cupboard at the top of the wardrobe is probably as good a spot as any. Tapes should never be left in direct sunlight, not even for short periods, and if you have to transport them by car, put them in the boot, not in the car itself, as sunlight coming through glass can create a lot of heat.
Wind all tapes before storing, as described earlier in this article, and put open‑reel tapes in plastic bags before putting them in their boxes, as an added precaution against dust. DAT tapes should be kept in their library cases, and if you have a DAT storage system to put these in (such as the 3M dual DAT cases pictured elsewhere in this article), so much the better. I'm not promising that you won't ever have tape troubles, but if you treat your tapes with a little respect, such problems are far less likely.
Just For The Record
Something that has to be decided upon fairly early when arranging your material for release is the total running time, and how that relates to the medium you're going to release it on. The running time of a cassette can be significantly longer that of a CD — cassettes are limited only by the maximum length of tape that you can get into the cassette shell, while the maximum CD recording time is 74 minutes (and most commercial releases are no longer than 60 minutes in length). In the case of vinyl, it's best to discuss the recording length with the company handling the cutting, as the type of material can affect the maximum playing time.
Never send off an Original Master tape, and if you've paid to have a Production DAT Master made up, then it makes sense to get one or two clones made at the same time, so that you don't risk losing or damaging the original.
Test Tones
Conscientious though you may be with your tape labelling, it isn't enough to know what is on a tape — it's also wise to indicate how high the signal level gets when the music is at its loudest. Analogue recordings are normally preceded by test tones for this purpose — although these don't give an entirely accurate picture of peak signal level, because different engineers tend to push the record level into the red to a differing extent. To ensure that the left and right channels haven't been mixed up anywhere along the line, the tones should start with a burst in the left channel only.
There should be five seconds of 1kHz tone on the left channel only, followed by around 30 seconds of the same tone on both channels recorded at 0VU. To assist in optimising the replay tape machine alignment to the tape, a 100Hz, 0VU tone should be recorded, followed by a 10kHz tone at around ‑10dB. All tone levels should be recorded on the box or label.
One exception is the Production Master for CD (or other digital format) manufacture. This usually includes no tones, to avoid the possibility of the test tones accidentally ending up on the album, which would be disastrous. Furthermore, at the PQ‑coded Master stage, everything that is present on the tape will usually be included on the final CD, so it is not wise to include test tones on this version of the material. If it is necessary to check the peak level, the material has to be played through and the peaks noted manually.