Hi Alexandre, in my musician days I used to do a bit
of sampling of sounds, for mapping to keyboards.

The click problem you are getting is very typical,
and the solution is very easy, just shorten the
total sample by one unit (one byte?) at a time until
the click is gone. You normally only have to chop
it ten or so times until you get a good loop.

Most good PC audio programs will let you select
"loop length" where you can listen to the repeated
loop until it is clickless.

There are a couple of ok shareware PC programs
that will do what you need, Cooledit and Wave-edit
or similar names. If you have been trying to get
a fixed length loop clickless that is almost
impossisble task!! Just change the end point until
it is clickless, nice and easy.
:o)
-Roman


Alexandre Guimar=E3es wrote:
>=20
> Hi,
>=20
>     This question goes to the more math enlightened of the list :-)
>=20
>     I have to make an audio noise generator that has to repeat a narrow=
 band
> noise over and over again. I have enough memory to hold 0.5 segs of noi=
se.
> My problem is that when I get from the end to the begining of the cycle=
 I
> always get a click on the sound output. I have already tried to apply a
> number of "windowing" functions ( Hamming, Kayser and etc.)  to try to =
make
> the begin and end of the noise to be as close to each other as possible=
 but
> it has not worked ! I also have tried to match it by hand with wave edi=
tors
> and have not been able to get good results !
>=20
>     The question is : Is there any way to generate white noise, filter =
with
> 3 db by octave filters and make it so that the begin and end of the wav=
e can
> be tied together without generating and audible click ??? I need 16000
> samples at 32K sample rate. I never imagined that human audition would =
be so
> sensitive to phase differences !!
>=20
>     I have really tried all the ways I can imagine and would really
> apreciate any help you guys could give me.

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.