In 2004, traders begun a massive coordinated effort to preserve the music in as good quality as possible for current and future live concert enthusiasts. Traders have scoured the world to track down the lowest possible generation of each source of each show. (Sometimes it has proved to be impossible to get in touch with the person who owns the master tape, so traders look for the next best thing - a first generation copy.) This lowest known generation is then transferred to FLAC. Currently, most audio trading takes place on this format.

Many shows were recorded by audience members to analog cassette. This master tape is known as the 'analog master', or ANA(M) in traders' shorthand notation.

The taper would then trade out copies of his master cassette: a direct copy of the master tape is known as a 1st generation cassette, ANA(1) in shorthand. A copy of the 1st generation copy is an ANA(2), etc. Generally speaking, the higher the generation copy, the worse the sound quality, since copying cassettes is an imperfect process and adds tape hiss and distortion to the sound.

Recordings can also be taped onto Digital Audio Cassette (DAT), an obscure format used by industry professionals. A master tape in this case would be listed as a DAT(M) in traders' shorthand. The advantage of DATs is that they can be cloned digitally, i.e. copied without any quality loss (unlike audio cassettes). However, it is important to keep track of digital generations as well (in case of problems or faulty copying somewhere along the chain), so a DAT copy of a DAT copy of a DAT master, for example, would be a DAT(2).

Analog cassettes were often transferred to DAT so that they could be copied without further quality loss, for example, a DAT transfer of a second generation analog cassette would be listed as: ANA(2)>DAT(1).

It is far from simple to determine what actually is the 'best' available source, as we shall explain. There are six crucial factors:

  1. Different Sources.

    Often, concerts are recorded by more than one person on different equipment. Which one is better will depend on the quality of equipment used (for example, a DAT recording using an expensive microphone will sound better than a Dictaphone recording). The positioning of the taper within the concert arena is also a crucial factor: Generally, the near to the speakers, the better the recording sounds.

  2. Length of source.

    Sometimes the better/best sounding source may be incomplete, so collectors who like to collect complete concerts will opt for the less good sounding source. Sometimes tapers arrive late, or their batteries fail, which results in incomplete recordings.

  3. The generation of the source used for the transfer.

    The lowest generation source is usually produces the best sounding FLAC's. In general, we assume that a FLAC transfer of, say, an ANA(2) will be better sounding than an ANA(3)>FLAC.

  4. Completeness of the source tape.

    There have been occasions when the FLAC's made from the lower generation tape, e.g. ANA(2)>FLAC, has been found to be less complete than a ANA(3)>FLAC from the same original source.

  5. Quality of analog copying.

    It is, of course, possible that an ANA(2) can sound worse than an ANA(3): for example, if an ANA(1) was copied on a boom box onto poor quality cassette, this will probably sound worse then an ANA(1) copied twice using state-of-the-art hi-fi equipment onto expensive tapes. The only way to detect if this is the case is to listen to each tape carefully.

  6. Quality of the transfer to FLAC.

    Another important factor is the method used to transfer the cassette to FLAC: the quality of the transfer depends on the skill of the person who transfers the tape, and the quality of his equipment.