There is a wealth of creative opportunity in the reel-to-reel tape recorder, whether stereo or multitrack, that is often underexploited. Perhaps it doesn't have the same glamour potential as sitting at the mighty mixing console, operating the faders, or the convenience of exploring the latest synth presets on a ROM cartridge. But this is real get-your-hands-dirty sound engineering, and the results can be well worth the effort. Indeed, even in the digital age, there are still a few tricks that you can only do with analogue tape - unless you have the tens of thousands of pounds necessary to buy the latest in hard disk digital recorders.

All this creativity can be unlocked at the cost of £50, maximum, for a few bits and pieces, and a few hours practice in the techniques of tape manipulation. Even when affordable digital equipment can do everything that tape can, the skills learned on the trusty Revox (or Fostex or Tascam) will be extremely valuable still.

TAPE EDITING

Cutting the tape and joining it together again is the basic operational technique, which can be employed in a variety of ways. But let's look first at the basics of cut-and-splice editing and how to do it.

Editing is the process of removing, re-arranging and altering material. The Editor of this magazine carries out the editing process on my articles; by removing excessive grandiose verbosity and pompous circumlocution (will he let that one through I wonder?), by arranging the main text and any sidebars into a form that will look good and make sense on the printed page, and by correcting any spelling mistakes he may recieve (receive?) in the typescript.

Editing a tape recording can achieve similar ends. A song may be recorded with one chorus too many, or perhaps it may be realised that it should start with a chorus instead of a verse. Also, there may be a false start or spurious noises at the end which need to be removed. One of the best things about having tape editing know-how is that you can record with the expectation of being able to correct or improve the work after the event, when the musicians have packed up and gone home.

Even before the widespread use of tape recorders, radio shows were extensively edited. They would be recorded on 78rpm disc, and choice segments would be re-recorded onto another disc ready for broadcasting. Of course, re-recording involves a quality loss; cutting and splicing tape, when performed correctly, does not.

The equipment necessary for tape editing is minimal: editing block, razor blade(s) and splicing tape. All of these are specialist items. The editing block was invented by a chap called Joel Tall - of the Editall company. Before the invention of this handy gadget, tape was joined by cutting with scissors and lining the ends up manually. The editing (or splicing) block is a lump of aluminium with a precisely machined groove running along its length. The groove is the same width as the tape and has lipped edges (see Photo 1 and Figure 1). The tape is pressed into the groove and is held in place by the lips.

Two more grooves are machined into the block, this time running at 60 degree and 45 degree angles to the tape. These are used in conjunction with a razor blade to cut the tape at a precise angle.

The razor blade is a stiff, single-sided blade sold by studio suppliers specially for the purpose. It won't fit in your Gillette, and neither will an ordinary double-edged razor blade do to cut tape. You'll need all your fingers later on in the procedure.

Splicing tape, too, is made precisely for the job in hand. The warning is often given never to use Sellotape or its equivalents, and it is well founded. Proper splicing tape has exactly the right amount of 'stick' so that it will hold the tape ends together firmly, even when fast winding, and yet will allow the possibility of peeling the joint apart if it doesn't come out quite right. Also, it will not ooze at the edges and deposit sticky glue on adjacent turns of the tape.

A fourth essential item is a white wax pencil (commonly available under the 'Chinagraph' brand). This, unlike the other pieces of kit, is not a specialist audio item and can be found at any decent stationery or art shop.

MAKING YOUR MARK

Let's imagine a typical editing scenario. You have a finished stereo recording (15 or 30ips) of a song that you want to shorten. Perhaps it has one chorus too many and you want to cut it out completely. First, gather together your equipment and put on your headphones so that you can hear clearly.

Play the tape up to the very start of the chorus. Listen to the drums, particularly the bass drum. In many cases the first beat of the chorus will start with a bass drum, overlayed by other melody and harmony parts. In every case, it is the rhythm that is vitally important, so listen for the bass drum beat that marks the precise rhythmic beginning of the chorus and ignore any less precise musical lines.

When you have listened to the chorus a couple of times and you are sure you can identify the start accurately, play the tape up to the start again. As soon as you hear that first bass drum beat, stop the tape. The beat you want on the tape is now a couple of inches to the right of the playback head of the tape recorder.

Press the edit switch of the recorder (sometimes labelled 'cue'). All professional recorders have an edit mode. Sometimes this is accessed by pressing 'Stop' twice. In edit mode, the tape will be pressed against the heads but the motors will not be turning. Now you can manually move the tape backwards by rotating the spools. As you do this, you will be able to hear the music in reverse slow motion. Listen for a 'sucking' sound, starting quietly and ending very abruptly - these sounds are drum beats. The deepest 'sucking' sound is the bass drum. After a bit of practice you will find this very easy to recognise.

Finding the correct bass drum beat is a matter of stopping the tape in the right place, then counting beats as you move the tape backwards. The faster you move the tape, the more clearly you will be able to hear the sound. Try and position the bass drum beat so that it comes just before the centre of the playback head, then mark the tape exactly in the centre of the playback head with a vertical wax pencil mark (Photo 2). This mark must be within 1/8th of an inch of the start of the bass drum beat, perhaps a tiny space before it, but not a fraction after it. Figure 2 shows how precise it must be.

Let me say now that this is not necessarily easy, but it is very nearly always possible. If in doubt, mark the tape with your best guess and then go through the process again. You will be able to judge your effort quite clearly. If it is not absolutely correct, then try again. Cross out your first pencil mark, or you'll forget which is which later.

Once you have the first mark correct, you can mark the end of the offending section. The process is the same, but it is most important to realise that the end of the section is in exactly the same place as the beginning of the next. To define the end of a section, you actually mark the beginning of the next.

Now, after a procedure which will become second nature with practice, you have a tape with a section marked for removal.

CUTTING THE TAPE

Wind the tape back to your first mark. Hopefully, you made a prominent enough mark for you to be able to see it as you spool through the tape. Now you need to cut the tape at this mark. I'm told that it is a big event for a trainee surgeon to make his or her first incision in living flesh. Fortunately, you will be practising on a copy of the master (I hope) before doing it for real. When you are an expert in the editing craft, then you will cut the master with confidence - without practice.

Photo 3 shows the precise position of the cut. Note that the mark is just to the left of the 60 degree groove in the editing block. This is so that you cut out all of the first beat of the section to be removed.

Cut the tape by drawing the blade smoothly across its width. (Whether you use the 45 or 60 degree groove is a matter of personal preference. The 45 degree groove should produce a smoother join, but I prefer the accuracy of the 60 degree cut).

After wiping the sweat from your hands (seriously, I may wash my hands several times during an editing session, to avoid contaminating the tape more than necessary), pull the tape through until you reach the second mark. Position the tape in exactly the same way in the editing block, with the pencil mark to the left of the groove to avoid cutting into the drum beat you want to keep. Cut the tape.

Now the two ends can be joined together. Place the ends in the groove and push them towards each other until they are as close as they can be without overlapping. A very slight gap will be inaudible, but any overlap will very likely give the game away. Cut a 1½ inch length of splicing tape, align it with the groove, lay it over the join and press it firmly down. Give it a firm rub with your fingernail to squeeze out the air.

The tape can now be carefully removed from the block and re-threaded on the recorder for auditioning (Photo 4).

So, what does it sound like? Play the join again, because the first run through will have helped to bed the joint down. On a second run through it should sound exactly as though there was no join. This is the standard towards which we aim, and in the case of rhythmic music with a drum backing it is virtually always attainable. If it doesn't sound right there may be two possible causes:

1) You didn't mark the tape in precisely the right place, causing either a double beat or a dull first beat. Look again at Figure 2 to see how precise it must be.

2) The music wasn't played in exact rhythm in the first place. If it's your own music, then you will be aware of this. When editing other people's recordings, you often find that the rhythm is a bit more 'tricky' than it might seem on a casual audition.

To problem 1, there is always a solution - more practice and attention to detail. To problem 2, the only solution is listening carefully to the music, and having enough editing experience to know where to make the cut for best results.

Of course, this is a simple example. Life is not always so simple. Sometimes the vocalist will anticipate the rhythmic beginning of a section; other times you will find that sustained instruments overlap the join and you hear a 'bump' as it plays through. The answer to both of these advanced problems is to be more creative in the selection of the editing points. As long as the rhythm matches up, you don't necessarily have to cut at the beginning of the bar, or on a bass drum beat.

The hardest type of music to edit is classical orchestral. Often, there is no precise rhythm, and some composers manage to avoid using any nice 'crunchy' sounds that would help to mask the edit.

But upbeat popular music is usually pretty straightforward. I have only described how to remove a section of music, but a recording can be extended by copying onto another tape recorder (taking care to match the levels) and splicing a segment back into the master. This is one of the techniques employed in the making of 12" mixes.

In my own music, I occasionally find that I don't have time, in the length of the track, to exploit fully all the instrumental variation on the multitrack master - especially if new ideas have arisen during the track-laying process. Here, it is a simple matter to mix the whole track, then create additional mixes of segments of the track with some instruments cut, others boosted. These segments can then be spliced back into the master ¼" tape where musically appropriate.

The potential is great, and I very much look forward to the day when I'll be able to edit my DAT masters. I will not be cutting the tape, but I will be using the skills of editing to choose good places to make the joins, and to arrive at a satisfying musical result.

If you own a suitable reel-to-reel tape recorder, have a go at tape editing. You may be surprised at what you come up with.

This is a manipulation technique that doesn't involve cutting the tape. It is useful either for creative effects or for fixing wrong notes or clicks on the multitrack tape.

Some multitrack tape recorders have a spot erase feature (such as the Tascam MSR16). Some, including the Fostex E16, don't - but I have found a way to do it (and most likely several other people have, too).

Suppose you have recorded a guitar solo which is perfect except for a click somewhere in mid-phrase. You can't punch it out in the conventional way, because it is too close to material that you want to keep.

Using the edit function of the machine, find the click and mark it with a wax pencil. Now, you need to rethread the machine as shown in Photo 5.

As you can see, the tape is not pressed against the capstan by the pinch roller. If you now press 'Play', the reel motors will apply tension but the tape will not move (assuming it is a three motor machine, which it probably will be). Practice moving the tape backwards and forwards by hand.

Once you have the knack, position the marked click exactly over the erase head. Put the machine into record mode, with no input, and move the tape backwards and forwards over half an inch of tape either side of the gap. Press 'Stop'. If you now re-thread the machine in the conventional manner and play the tape, you will find that the click has miraculously disappeared.

There are three important points to bear in mind here:

• When threaded in the manner shown, the tape may not pass through the tape guides, resulting in an imprecise tape height. You may therefore end up erasing the wrong track. You can, by experimentation and observation, find out whether this will be the case with your machine.
• The machine may record a click on the tape when exiting the record mode with the tape stationary. If this is the case, then spot erase may not be possible on your machine.
• This procedure may incur a slight possibility of damage to the tape and the machine. I have consulted with the service departments of the distributors of my Revox and Fostex machines, who believe that damage to the machine is extremely unlikely; but to be fair, it's likely that not many people are currently using their machines in this way.

I personally accept that, in the pursuit of artistically beneficial results, I incur the risk of having to pay for repairs to my tape recorders. You must make your own judgement on this.