BRAMSHILL Speech Collection - Background Information
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1. Introduction
   ============

    This file, DATACOLL.DOC, provides additional background
    information concerning the environment in which the
    recordings were made.

2. History
   =======

    The recordings on this CD-ROM set were originally made in
    1978-79 as part of a British Home Office study into speaker
    identification techniques.

    Subsequently, it was realised that a large body of
    unconstrained conversational material might be of interest to
    researchers working in other speech processing fields. The
    advent of CD-ROM as a convenient and relatively cheap
    distribution medium, in combination with the problems of
    storing the original 1/4 inch computer tapes, provided the
    impetus for the BRAMSHILL project. The recordings were
    transcribed and the CD-ROMs prepared during late 1993 and
    early 1994.

3. Recording Environment and Equipment
   ===================================

    The recordings were made at the Police Staff College,
    Bramshill, Hampshire England (hence the name BRAMSHILL). The
    participants were police officers taking part in the various
    courses at the college. This provided a wide range of regional
    accents and a range of ages from late teens to early fifties.

    Three adjacent bedrooms were used. The two participants, each
    alone in their rooms, conversed by telephone. The third room
    was used as a monitoring and recording station.

    In addition to the telephone recordings, reference recordings
    were made using a high quality dynamic microphone in each room.
    It is mainly these higher quality recordings which are provided
    on the BRAMSHILL CD-ROM set. In a few instances, the higher quality
    recording has not survived. In these cases, the telephone recording
    is provided instead. The items index contains "TELEPHONE QUALITY"
    in the comment field (field 7) for these recordings.

    The recordings were made on a Sony Elcaset EL-7 cassette
    machine, chosen at the time because of its good speed
    stability. Specifications of this machine were (at 3.75
    inches per second)---

    	Signal/noise		  59 dB
    	Frequency Response	  20-22,000 Hz
    	Total Harmonic Distortion 0.8%
    	Wow & Flutter		  +- 0.12%

    The microphone was a Shure SM-7 cardioid type.

    Some attempt was made to control the acoustic environment.
    Each room had a floor area of about 13 square metres.
    Normal bedroom furniture was left in place, and the carpeted
    area of the rooms was increased. One and a half walls of each
    room were covered by sleeping bags hung from the ceiling to
    1 metre above the floor. The rooms contained a chair and a
    table, on which the telephone and dynamic microphone were
    placed.

    It is evident from listening to the recordings that, while
    these measures produced a reasonable recording environment,
    the rooms were far from soundproof. A variety of external
    noises (engines, aircraft, etc) can be heard on some of the
    recordings.

4. The Conversations
   =================

    Each speaker was given a pile of photographs. The participants
    were asked firstly to order their photographs in pairs
    according to the reference numbers on the back. This part of
    the conversation was used to establish recording levels etc.
    It is not included in the recordings.

    Next, in response to a bleep signal, each speaker introduced
    himself or herself by name and read a set of test sentences.

    After this, the main part of the conversation took place, in
    which participants were asked to determine which of each pair of
    photographs has been taken first (if indeed they were related at
    all). In several cases, the participants misunderstood the
    instructions and attempted to arrange the complete set of
    photographs in sequence, rather than dealing with them pair by
    pair. The conversations continued for 10 minutes until terminated
    by another bleep signal.

    During the digitisation process, some periods of silence were
    removed, so most recordings now appear to be shorter than the
    original ten minutes. Furthermore, this means that recordings
    of two sides of a conversation are no longer time-aligned. In
    addition, to preserve the anonymity of the speakers, some
    passages (mainly the introductions) have been erased by
    replacing with binary zeroes. Finally the bleep signals have
    also been erased with binary zeroes. The transcriptions
    indicate where this has occurred.

    The standard test sentences are listed below. Usually these
    were spoken at the start of the recording.

5. Test Sentences
   ==============

    The best way to have really good cup of tea is to take a
    quick walk up the Great North Road.

    I had often thought a little yeast would cause a merry ape to
    sing in triumph at the zoo.

    Which police first caught the wolf champing rotten zebra bait
    near my goat house?

    Yes, judges do wear very thin soiled T -shirts.

    Above all you took some of her pink Union cheque books off
    the top cupboard.

    Who will be brave enough to go into town by car, and do just
    one more bad deed?

    You should pay no attention to the size of the beige coat and
    green hat she wears.