Labelling ABBA master tapes
by ABBAMAILer Ken Griffin

You never appreciate how important it is to label tapes properly until you produce a live broadcast. Admittedly, my tapes were actually minidiscs and my broadcasts were on a university radio station but the principle holds true whether you're an audio professional, a semi-pro or an amateur.

I never put much effort into labelling the contents of the minidiscs, but I did ensure that I had accurate technical notes about how to play them properly. This may sound odd but there were sound reasons for this.

Firstly, the minidisc players we had at the university had all sorts of exotic options ranging from long play to mono recording, from single track playback to continuous play, all of which were used by different people to a certain extent.

As a journalism student producing a current affairs show, I used to edit the outtakes for my reports to the end of minidiscs, which mean that single track playback had to be used for my discs. Other people used long play because they didn't want to buy too many minidiscs, so the machines had to be set for that. Others recorded too quietly so the playback volume on the mixing desk had to be adjusted before they could be played live.

With just two minidisc players, these various modes involved lots of button pressing. I found practically impossible to remember which modes to use one which discs so I had to note these things down to remind me to make the adjustments.

The other major reason was in case the item was repeated later on a show I wasn't producing. This never happened but, if it did, I wanted to ensure that whoever was playing the minidisc back knew how to play it properly.

So I was pleased to see that when I recently examined the photos of Abba master tape boxes published in the 2001 remasters, that they were littered with technical notes relating to their proper playback.

For instance, the master tape box for Abba: The Album side 1 has "15" NAB STEREO EQ-ED COPY FOR CUTTING" and "1000 / 15000 / 45Hz +0UV" written on it. All these codes are instructions for engineers playing the tape.

The 15" part refers to the speed that the tape should be played at i.e. 15 inches per second. Most albums made in the seventies were recorded at this speed, although speeds of 7.5 and 30 inches per second were also available.

The NAB part refers to a recording equalisation system designed to allow analogue tapes to record sound as accurately as possible by getting around some of their technical limitations. NAB altered the sound as it was recorded to deemphasise high-end sounds and emphasise bass ones.

When the tape was played back on a machine with NAB activated, this somewhat distorted sound would be converted back to normal. Strangely, NAB was a prominently American system and its particularly odd that Abba chose to use it as early as 1973 on the master tapes for Ring, Ring.

The "EQ-ED COPY FOR CUTTING" piece tells us that the apparent master tape isn't actually the real mixdown master! It's a copy that was sent to a manufacturing plant for LP production. The EQ-ED bit refers to the fact that the tape was equalised to balance the frequencies on it so it could be used for making LPs.

Equalisation of tapes for LP production is particularly important as some frequencies can make the stylus skip out of the groove. In that sense, it isn't really about improving the sound ­ it's more about ensuring that the sound can be accommodated within the limitations of LPs.

The numbers with "+0UV" after them refer to tones at the start of the tape with are use to calibrate the tape machine so that the sound is played back properly. Each tone should last about thirty seconds and each should be at 0db. If they're not, the engineer should adjust the sound output until they are.

There's no real consistency regarding the tones used on different tapes. In the case of The Album, there are tones for 45hz (a bass frequency), 1khz (a mid-range frequency) and 15khz (a very high treble frequency). But if you look at the tape box for side 1 of The Visitors, you'll see that a wide of ranges of tones were put on that tape. If there are no tones, the engineer has to guess the best calibration for the tape machine.

One interesting thing that is missing from the notation on all Abba's master tape boxes is a reference to Dolby, a noise reduction system that was ubiquitous in studios in the 1970s. Like NAB, Dolby was applied to tapes as they were recorded and would have been to be decoded by the machine they were being played back on.

Dolby was concerned with noise reduction. If a Dolby tape was played back on a machine with Dolby off, you'd get a horrible thin sound, similar to playing back cassettes made with the home version of Dolby with Dolby switched off. It's unclear from the boxes whether Abba didn't use Dolby or whether it was so readily used, that whoever who wrote the notation assumed that Dolby would be enabled on the playback machine.

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