[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: tapping hardware & software
I concur with Christian's idea of using a cheap microphone
to record the tapping, assuming the subjects listen with
headphones to avoid crosstalk. However, to get accurate
timing measurements you will need to record the mic and the
stimulus on separate (L and R) sound card channels. (Sound
card L and R inputs are always synchronous with each other,
and L and R outputs are synchronous with each other, but
the outputs are not synchronous with the inputs, so you
need to record the output as an input.)
Since sound card Mic inputs are always mono, you will need
to use Line In, with an external preamp to boost the mic.
(You might be able to get away without the preamp, since
this task doesn't require high fidelity and the mic can be
placed very close to the subject... the subject could even
tap directly on the mic.) Then all you need is to route
the stimulus to (say) the left Line In, and the mic output
to the right. This will require some "trick" cabling,
either by cannibalizing cheap sound card cables or buying
I think my Daqarta software for Windows can do the whole
job. It can do all sorts of pulse and tone burst
generation (and just about anything else you can think of),
and it can play sound recordings as stimuli as well. Let
me know the details of what you want, and I can help you
create a stimulus setup. Daqarta can then record the
combined signal to a file.
As far as analysis goes, I have no experience with
Christian's suggestion of Octave, but it sounds like it
would do the job. Daqarta can do some of this
intrinsically: You can scroll through the file manually,
of course, and measure the relative times with on-screen
cursors. But a better way is to use the Trigger controls
in Single mode, such that the file scrolls automatically to
the next tap or stimulus event (which would be under one
cursor), and you'd then place the other cursor on the other
event (stimulus or tap) and read the timing difference
directly on the Delta cursor readout. Then you hit the
Trigger button to advance to the next event.
Daqarta has a macro scripting facility, so in principle
much or all of this could be automated. But some of the
features needed to do this particular task won't be
available for a couple of months yet.
A Daqarta Professional license is US$99, but you can try
everything free for 30 sessions or 30 days. After that,
you can still analyze files, but you can't record from the
inputs. So if you can collect all your data in one month,
you can do everything for free!
On 24 Mar 2011 at 9:32, daniele schon wrote:
> Dear all,
> I am trying to think to a simple and cheap solution to record children
> in a tapping task (eg along with a metronome or a piece of music).
> I have up to now found several solutions commonly used, but none of them
> is cheap. For instance, using a software such as Presentation to send
> the auditory stimulus and record with the space bar (requires
> Presentation/E-Prime license), or using Cakewalk and a tapping pad
> (requires Cakewalk license and a tapping pad).
> So I would be glad if you could share your advice on the "optimal"
> solution, optimizing the real cost (in euros), the precision (in
> milliseconds) and the other cost (the hours I'll spend analyzing data,
> for instance recording the tapping on a microphone ...).
> my warmest regards
> Daniele Schön
> Equipe Langage, Musique et Motricité
> Institut de Neurosciences Cognitives de la Méditerranée
> C.N.R.S, 31, Chemin Joseph-Aiguier
> 13402 Marseille Cedex 20, France
> Tel: 0033 (0) 4 91 16 41 30
> Fax: 0033 (0) 4 91 16 44 98
> I CHOOSE PEACE
D A Q A R T A
Data AcQuisition And Real-Time Analysis
Scope, Spectrum, Spectrogram, Signal Generator
Science with your sound card!