Music on the XO

[Jean Piché]

SJ,

Two things.

More important:

Free music is a great concept... for people who have global access to  
ineternet-based music pools. Given enough "community mass" and  
discernment on the part of the listener, one can get to the  
subjective and elusive concepts of  "quality"  and "exemplariness".   
The problem here is that OLPC, by the very fact it will include  
collections of music by "curated" artists out of the free music  
ethos, gives a value imprimatur where perhaps none is warranted. We  
dont need a discussion about music's influence on culture but I think  
everyone will agree its serious business in the education and  
socialising of a child, increasing manyfold in adolescence. Alas,  
much of the music that is presently included in the Jamendo  
collection is, to be honest, dreadful in style and of rather poor  
quality in production.  I am perhaps not in a position to be an  
arbitrer any more than the undoutedly generous and sharp young minds  
at Jamendo but I suggest OLPC thread VERY carefully here. Even when  
there is quality, I am not certain what to think of Nigerian children  
being fed a diet of DJ Spooky, no matter how much I personally enjoy  
his work...

We should be discerning about what we wish for. "Open System" ia not   
"Open Culture".



Less important:

A head's up on the XO audio subsystem: The speakers have a severely  
biased frequency response. We have recently performed a thorough  
analysis of the audio response curve of the machine and there is a  
spectacular 12dB peak between 3000 and 4500 Hz, this on all models.   
I suspect these are mobile phone speakers designed for voice clarity.  
What this means is kids will likely crank up the volume so that they  
can hear some of the lower frequencies. Since the physical size of  
the speakers prohibits any frequencies below 350 HZ,  as they try to  
get a decent bandwidth,  they will get the "membrane-against-the- 
casing"  distortion (which has the merit of making the kids lower the  
volume but  risks killing the speakers if done routinely). Someone on  
the hardware side really should look at the long term prospects for  
audio hardware failure and see what correction we can bring, by  
limiting signal output and/or equalising the output of the AD1888 (we  
dont know what can be done on chip...)

The solution we have implemented in TamTam  is to simply apply a  
reverse notch filter on the audio signals we send to the speakers.  
This works well and provides a more pleasant listening experience,  
but inevitably reduces the dynamic range. It does nothing per se to  
protect the speakers becasue you can still crank up the volume to  
casing distortion. Furthermore, our solution only works with the  
speakers of course, since the line out/headphone output produces an  
acceptably neutral signal. Thus, to make it sound good in the  
speakers, we make it sound bad in the earphones. Unless there is a  
signal we can access that tells us when the line out jack is  
connected....  Anyone know?


jp (ethrop)



_________________________________
http://jeanpiche.com

On 26-Oct-07, at 9:33 PM, Samuel Klein wrote:

>
> Jamendo has been hard at work compiling albums of music and  
> confirmations
> from their artists, coordinating the work of dozens of curators and
> smaller partner sites.  You can see some of the results of their work
> here:
>
> http://www.jamendo.com/fr/olpc
>
> There will be a "contribute music" interface soon; for now, you can  
> send
> albums and interested artists to Romain directly (cc:ed here).  And  
> there
> will be more information put up about the artists involved.
>
> This has come together thanks to many people, but especially the  
> crews at
> Jamendo, Free Culture, and the Antenna Alliance.  You all rock.
>
> If you have contributed music in other formats that doesn't  
> currently show
> up on the page listed above, let us know; and make sure that you have
> confirmed the license of your works.
>
> Cheers,
> SJ
> _______________________________________________
> Library mailing list
> Library at lists.laptop.org
> http://lists.laptop.org/listinfo/library

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