[erlang-questions] Generating sine waves and/or audio stream output

G.S. <>
Thu Mar 25 10:05:50 CET 2010


Hello Willem,

Could you also please send me the code if possible? as I am also highly
interested in using Erlang for sound generation.

Regards and thanks,
-Gene

On Thu, Mar 25, 2010 at 1:51 AM, Ivan Uemlianin <> wrote:

> Dear Willem
>
> Thanks very much for you email and your code.  This looks good.
>
> The functions generate binaries.  Do you stream the binaries to audio or do
> you write them to a file?
>
> Do you have a function that writes wav files?  If not I shall write one
> (unless a function to stream to audio will be easier but I don't think it
> will be).
>
> Thanks and best wishes
>
> Ivan
>
> Willem de Jong wrote:
>
>> Hello Ivan,
>>
>> I have an erlang module that generates sounds. It can generate different
>> wave forms (right now all I need is a saw-like shape and a sinus shape). I
>> am attaching it. It is a bit messy, perhaps, but it should give you an
>> impression of how it can be done.
>>
>> The synthesize() function uses the sinus() function to create a number of
>> complete waves, and then pastes  these together repeatedly (I assumed that
>> would be more efficient that calculating the sinus() function for each
>> sample).
>>
>> The syntesize() function returns a couple of sound fragments: an "attaque"
>> bit that starts with an amplitude of zero, a fade-out bit where the volume
>> decreases back to 0, and a long and a short bit of sound with a stable
>> volume. Another module creates a complete sound-fragment of the desired
>> duration by pasting together the attaque, a number of long fragments and
>> short fragments in such a way that it matches the duration (as precisely as
>> possible), and a fade out bit.
>>
>> As you can see this creates sounds with a fixed pitch and volume (within
>> one sound, that is). Also note that both the length and the pitch of the
>> sound will be approximations.
>>
>> I created this to generate music for my web-site: http://coria.nl.  You
>> can try the result there, if you want. It is a site that enables me and the
>> other members of my choir (and anyone else who is interested) to practise
>> our music.
>> Any comments or suggestions will be quite welcome, Good luck,
>> Willem
>>
>>
>>
>>
>> On Wed, Mar 24, 2010 at 11:28 AM, Ivan Uemlianin <<mailto:
>> >> wrote:
>>
>>    Dear All
>>
>>    I am learning Erlang and one of the things I'm interested in is
>>    generating sine waves, merging them and streaming them to audio
>>    output.
>>
>>    I can kind of imagine how generating and merging would work, with
>>    a sine
>>    wave represented as a list of numbers.  Is there an Erlang library or
>>    project working with sine waves?
>>
>>    I can't imagine how to stream a list of numbers to audio output.  Can
>>    anyone point me to projects/libraries/ideas for that one?  Writing the
>>    data to a file would be OK for now, but "live" sound would be much
>>    nicer.
>>
>>    With thanks and best wishes
>>
>>    Ivan
>>
>>    --     ============================================================
>>    Ivan A. Uemlianin
>>    Speech Technology Research and Development
>>
>>                       <mailto:>
>>                       www.llaisdy.com <http://www.llaisdy.com>
>>                           llaisdy.wordpress.com
>>    <http://llaisdy.wordpress.com>
>>                       www.linkedin.com/in/ivanuemlianin
>>    <http://www.linkedin.com/in/ivanuemlianin>
>>
>>      "Froh, froh! Wie seine Sonnen, seine Sonnen fliegen"
>>                       (Schiller, Beethoven)
>>    ============================================================
>>
>>
>>
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>
> --
> ============================================================
> Ivan A. Uemlianin
> Speech Technology Research and Development
>
>                   
>                    www.llaisdy.com
>                        llaisdy.wordpress.com
>                    www.linkedin.com/in/ivanuemlianin
>
>   "Froh, froh! Wie seine Sonnen, seine Sonnen fliegen"
>                    (Schiller, Beethoven)
> ============================================================
>
>
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