THE REASONS FOR wanting to sync a sequencer to tape are fairly obvious - running your sequences with your multitrack saves tape tracks and keeps editing options open. Then, at the mastering stage, your sequenced instruments will be going to tape for the first time, hence optimising sound quality.

The problem with MIDI's own clock is that its bandwidth of 31.25kHz is beyond the recordable frequency of an analogue tape recorder. The cheapest solution to this incompatibility is to use a tape sync-to-MIDI converter. These use a technique called Frequency Shift Keying (FSK) which encodes MIDI clocks into a signal the tape machine can record as the sequencer is playing - by using this method, tempo changes may also be recorded. On playback, the converter regenerates the MIDI clock and uses it to keep the sequencer in sync with the tape recorder.

However, FSK units have the disadvantage of requiring you to run the song from the beginning each time, as the sequencer needs to receive the MIDI Start command from tape before it will play back a sequence. Consequently, some FSK units also use MIDI Song Position Pointer information; this allows you to run the tape from any point during a song safe in the knowledge that the sequencer will pick up the correct point in the song. This system is referred to as Intelligent FSK, and the latest unit employing it is Anatek's Pocket Sync.

Well, if you've seen one pocket device, you've seen them all - it measures around 3" x 2" x 1", and boasts only MIDI In and Out, and Audio in and out connections. Two LEDs on the top have multiple uses: a red LED indicates MIDI status - it stays on constantly if no MIDI data is passing through, showing that Pocket Sync is powered, goes off when MIDI data is received, and flashes in time with the tempo when receiving MIDI clocks from sequencer. A green LED indicates tape status - it's off if no tape signal is being received, on when tape sync is present, and it flashes in time with the tempo of the MIDI clocks being read from tape.

With any FSK-to-MIDI converter, the song has to be completed on sequencer, including any tempo changes, before you're ready to stripe timecode onto tape. Your sequencer has to be able to transmit MIDI Clock (practically all can), and support MIDI Song Position Pointer. The audio in and out from Pocket Sync are connected to the output and input sockets respectively of the tape track chosen for the purpose (usually one of the outermost tape tracks). The level of the sync signal on tape is critical - using Pocket Sync with a Fostex 280, a level of between -3dB and -8dB was fine but anything lower gave occasional dropouts in sync. On the other hand, if the level is too high, you get crosstalk (where the sync signal is clearly audible over recordings made on an adjacent track). Many modern multitrack recorders have a noise reduction defeat on one outer track, especially if they use dbx (which badly interferes with a sync signal). If your recorder has Dolby B or C, then you probably don't need to worry - Dolby C was left on during tests of the Pocket Sync and the results were still perfect.

On playback, the unit's green LED comes on as soon as the sync signal on tape is received. It then blips away quite happily to the tempo of the decoded MIDI Clock. Consequently, it's easy to use and very reliable.

If the MIDI In of the sequencer is connected to the MIDI Out of Pocket Sync, how do you connect your keyboard when your sequencer is locked to tape? Unfortunately, the answer is that you'll need to use a MIDI Merge box, as Anatek haven't put a switch on the MIDI In to turn it into a "soft thru" (which allows you to use Pocket Sync to merge the incoming MIDI note information with the MIDI Clock data being created).

Tape dropouts are bound to occur when working with cassette-format recorders. To get around this, Anatek have included a "jam sync" facility which causes Pocket Sync to continue to send out MIDI Clocks at the current tempo if the sync signal from tape is temporarily lost. This will continue for either ¼ of a second or 1 second depending on whether the Audio In jack is plugged in before or after power-up. Finally, the tape speed can be changed by up to 20% without losing sync - the tempo changes accordingly.

In conclusion, I can say that Pocket Sync is quick and easy to use - and cheap at £99 - but it's a shame that you need a merge box to record MIDI data to a sequencer while it is running in sync with a tape recorder.

Price £99 including VAT

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