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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 
"splitter" cables.

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!

Best regards,

Bob Masta


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
> -- 
> 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
> http://www.incm.cnrs-mrs.fr/pperso/danieleschon.php

Bob Masta
            D A Q A R T A
Data AcQuisition And Real-Time Analysis
Scope, Spectrum, Spectrogram, Signal Generator
    Science with your sound card!