It is not hard to see why. Most people willing to see the exhibits in an order chosen by someone else will prefer to follow a warmer, human guide. Those who want to flit from room to room, on the other hand, looking intently at a few exhibits and ignoring the rest, know that the tape may prove more trouble than it is worth. Finding the relevant parts of a taped tour could require endless rewinding and fast-forwarding.
Computer scientists have a name for the feature that the standard cassette tape lacks: random access, meaning the ability to jump directly to any portion of the stored information without having to read any other first. CDs, floppy disks and memory chipsall offer random access, yet in museums the old-fashioned cassette lives on.
The oddity of this was noticed three years ago by two Israelis, Shmuel Shalem and Giora Oron. The two men, one working in Tel Aviv for National Semiconductor, the US chip manufacturer, and the other chief engineer at the new Voice of America transmitter in Israel, had met in the Seventies while performing their military service, as most of Israel's citizens are required to do, and had talked about going into business together.
They realised that computer memory had become so small and so inexpensive that recorded museum tours could be converted to digital format and stored on semiconductors - and they set up a new company, Espro Engineering, to do just that. But a number of details would need to be settled before they could turn the idea into reality. Any substitute for the old-fashioned cassettes would have to be portable, secure, convenient and easy to use.
The two engineers knew that since museums tend to be conservative institutions, they would need help in bringing their product to market. So they teamed up with Acoustiguide, a firm that had sold its taped tours to such prestigious attractions as the Louvre, the Guggenheim, the Vatican, St Paul's, the Rijksmuseum and the Forbidden City in Peking.
With Acoustiguide, Espro carried out trials at the National Galleries in London and Washington and the Louvre in Paris to see what visitors wanted. One conclusion was clear: people did not want a machine strapped to their belt or a headset over their ears. Instead, they opted for a gadget shaped like an elongated mobile phone, which could be picked up and listened to at will, then hung from a shoulder when not in use.
Armed with this information, the firm went away and came up with a stylish black "wand", weighing just under 13oz, that can carry four hours of recorded tour. The tour can be divided into up to 1,000 different segments, which visitors can select by punching a number into the telephone-like keypad. Segments can refer to a room in a museum, a single object, or an aspect of that object, and can include music as well as speech. The wand contains its own battery, which runs for the entire day and is then recharged by being placed inside a storage rack that looks rather like an outsize cappuccino machine.
The clever bit is how the information finds its way into the wands. The museum tour, recorded in a studio, is copied on to a standard Personal Computer Memory Card International Association flash-memory card (see page 21). The card is then slotted into the storage rack, and the information stored on it is transferred to 25 wands at once in less than a minute.
The PCMCIA cards make the system flexible: the wands can be reprogrammed instantly with new information or the same information in a different language - so a sudden influx of Japanese tourists is easy to deal with. Using cheaper chips inside the wand reduces its replacement cost to only $500 (£324), a modest price for such complex technology. To protect it from thieves, the wand also contains a small receiver. If it is carried outside the museum, a transmitter at the front door instructs the wand to start beeping furiously, so that security staff can find it even hidden at the bottom of a bag.
Symptomatic of the French flair for combining the old with the new, the Louvre was Espro's first customer. It now has a bank of 600 wands for its visitors, available in six different languages and covering special exhibitions as well as the main collection. But other museums are beginning to see the advantages of the technology. Last week, the Tate Gallery became the first London institution to use it. Some 17 other sites are either already using it or are about to introduce it.
The attraction for museums and galleries is that the income from renting the wands - £2 a time at the Tate, FF30 at the Louvre, $5 at some US sites - can pay back within a year the cost of installation. The system should be particularly popular with visitors to institutions whose owners cannot afford to label or signpost them properly - such as the Taj Mahal in Agra, or the splendid Egyptological collection at the Cairo Museum. Espro also has plans to market an upgraded model that can handle an eight-hour walking tour through an entire city centre, and is considering applying the technology to helping visitors around the hundreds of stalls at international trade fairs.
But it is in long-distance tourism that the technology may have most potential. Contrary to the widely held belief that visitors from Japan and Korea all prefer to hunt in packs, many Asian tourists stick together only because of their lack of confidencein European languages. Increasing numbers of Japanese and Koreans are taking trips with their families or a few friends, rather than on a bus with 40 of their compatriots and as many camcorders. For them, a hi-tech museum guide talking in their own language is proving a godsend.