Wavetables. DefaultWaveTable

George

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Mar 24, 2022, 5:15:46 PM3/24/22

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I'm wondering about the format of the String in the file wavetables.xtm

There is a tempting invitation at the top of that file to experiment with some changes:

";; anything defined here should be kept as short as possible!

;; no big files!"

There are lots of people offering downloads of their 'wavetables' and even wavetable editors. Some seem to be .wav files. I can't see how that might help.

The only structure I can see in the String part of "wavetables.xtm" is the presence (among the total of 3200 characters) of 153 + characters which may possibly be separators of individual items ??

Reluctant to just make some random changes ...... but I might do that and see what happens ........ unless I hear a better idea.

Does anyone have a suggestion ?

Regards

George

Andrew Sorensen

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Mar 24, 2022, 7:26:14 PM3/24/22

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Hi George,

The "string" is 32bit floating point, interleaved, base64 encoded PCM audio data. The number of frames, channels, and samplerate and then defined in the constructor.
Please feel free to add but keep in mind that this is inlined so keep as small as possible (i.e. keep number of frames to an absolute minimum).

Cheers,

Andrew.

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George

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Mar 25, 2022, 3:13:37 AM3/25/22

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OK Andrew. Thanks

A lot of words there I'm not totally conversant with.

I did find that when I saved just the data between quotes in a file (I called it noise.txt) I can import it as raw data into Audacity.

It magically plays a very short mono popping sound. 0.036 sec long.

From Audacity the "file > export > export audio...." option allows an export as a noise3.wav with encoding "signed 32 bit PCM".

The resulting noise3,wav file plays a similar sound on Audaciy and Music.app

Opening noise3.wav in BBEdit.app shows what looks to be exactly the same data as the original string from wavetables.xtm except that each pair of characters is separated from neighbouring pairs by double inverted red question marks which render like so in the BBEdit find dialog : \x{00}\x{00}

When I eliminate all these characters it seems I get back to the original !

Anyhow in this roundabout way I think I could get a short wav sample from somewhere and construct a set of characters to make an alternative wavetables.xtm file of about the same length and see what effects that has. Presumably there will be some changes the standard syn1, syn2, syn3 sounds.

Not sure what "interleaved" means. Nor "number of frames". I see the AudioBuffer specifies 600 frames ??

Is this worth a try or am I barking up the wrong tree here?

Regards

George

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Mar 30, 2022, 5:54:09 PM3/30/22

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Came across interesting App called WaveEdit.

Makes lots of interesting sounds which could form the basis on an alternative wavetables.xtm ??

However the files come as "Banks " of files.
I suspect that extempore might be able to handle just one member of a bank.

Any ideas on that.

Any ideas on what kind of characteristics one might go for if replacing the current wavetables.xtm ?

What is it about the current wavetables.xtm that made it suitable for the standard extempore ??

Haven't tried anything yet - just thought maybe some has had some experience with fiddling with DefaultWaveTable.