audio recorders

[Stefanie Brosda]

hello all, and sorry for those who are not concerned/interested in this.

i am currently recording babbling data and do confirm what brian wrote.

the surrounding noise can be rendered VERY audibly on the recording even
when in the situation you were hardly aware of it (due to some kind of
perceptive
filtering of ours). a computer in the room you're recording in should be
shut down as it is rather imposing on the tape afterwards. refridgerators
are a problem, too, if the child happens to be in the kitchen for daily
routines, but its less disturbing then a computer's ventilator. (anyway,
people generally are not prepared to switch off the fridge for you... :-)
). more obvious things like washing machines and open windows have to be
avoided, too. this may seem evident to us, but the parents of your
babbling babies are not necessarily aware of this things until you tell
them.

personally, i used a DAT recorder in the beginning, then changed for a
digital camcorder (CANON MV20i - afterwards i extract the audio track from
the video files with adobe premiere). there has not been any quality
change between the two devices. the mike i use is a PHILIPS SBC ME600
very small clip mike, frequency range: 50 - 18 000 Hz, impedance: 1000
om., sensitivity: -65 dB, 5 meter cord.
depending of your funding, you might consider to use a cordless mike which
i think significantly facilitates things as the cord intervenes with the
child moving around, is used as a toy, being sucked on etc.
as for the placement you'll need to find a compromise between having the
mike as near to the child's mouth as possible but still out of touch and
reach (which is in itself not possible...). i found that clippig it on the
shoulder or a bit below works fine. be careful not to clip it to near to
the face as the child will be moving around his/her head and be touching
the mike with his/her cheeks. this completely plasters the child's output
with noise. same for contact between the mike and clothing.


>    Of course, there is always the sound-proof room approach, but then the
> child may just decide that they don't like babbling in sound-proof rooms.
> I wonder if babbling researchers have ever tried that approach.

well, i did not. and i should not think it works.

- unnatural surrounding for both the child AND the mother (if the mother's
not as ease, the child won't be either)

- no daily routines possible

- at least "my" mothers/fathers would not have liked to have to come into
the lab especially instead of me going to their homes

- organisational problems: i found it sometimes difficult to find the
right moment to record the children (what with naps, meals, naps again and
other time constraints imposed by the child or the parents) which are not
always fully forseeable. but in order to have the caregiver+child in the
sound-proof room at the right moment when the child is good humoured,
relaxed and in a chatting mood, you'd need considerable prediction
capacities that are difficult to acquire...

good luck and best wishes,

stefanie brosda


                /\/\  /\
           /\  / /--\/  \  /\
          /__\/ / /\/ /\ \/--\
         /    \/ /  \/--\ \   \
Stefanie BROSDA
Institut de la Communication Parlee / INPG
UPRESA CNRS No 5009
46, Av. Felix Viallet
38031 Grenoble Cedex 1
FRANCE

Tel: 	(+33) 4 76 57 48 27
          --  - -- -- 45 41
Fax:	(+33) 4 76 57 47 10
E-mail:	brosda at icp.inpg.fr