WaveTable from x0xb0x for Java Synth!

[Acidfloor]

Hello!

I'will make a TB-303 Synth in Java, and need a "WavewTable" from the x0xb0x!
How can i make the wavetable (with software?)? Can i download the wavetable
from the eeprom?

Who can me help me?

Bye
Erik

[antto]

hi
i guess you want to "sample" the oscillator waveforms?
if that's so, uhm..
well, simply there is no point in sampling the sawtooth as it's pretty much a standart sawtooth
as for the square, it's not so easy
you can't put 1 cycle of the square into a table
the square wave on the 303 (and x0x) is a very odd thing
the "shape" changes depending on the frequency, and it changes a lot, and this is why it sounds so unique

what you _can_ do is to use a cheap approximitation instead
there is already information available you can try stuff out or simply do your own research
for a cheap and fairly good approximitation you need to match the following properties:
1) the pulse width
2) the softness of the softer edge
3) the amplitudes of the edges
all of the 3 things depend on the osc frequency

if you actually want to get inside the x0x (i guess you have a x0xb0x, right?) i've also done this
you can record both waveforms (raw) at the same time by hooking 2 probe clips (Left / Right) to the waveform switch, connected to your PC, and one clip to ground
also, i used 100k resistors for the probe clips because otherwise they mess up the normal behaviour of the VCO
a better option would be if you have an oscilloscope, but i don't have one

there is however a problem with the soundcard recording thing - your soundcard probably has a DC-filter on the input, so your recording won't be "raw" .. it will be the VCO high-pass filtered
you can fix this with an "inverse" filter to a certain point

and btw, there is already a JAVA 303-like synth, it's a standalone app, i can find the link if you want to check it out..
feel free to ask about anything

[antto]

uhm, for the square.. you could also make an array of 1-cycle tables
something like 1 table per note, the usual range of the sequencer is about 5 octaves, that's 6 notes
however, this means:
1) your "slide" feature will be CPU intensive since you'll have to interpolate between tables, and it'll also sound jerky i guess
2) if you also put Fine Tune knob - it won't sound very good

to fix these - you can make the array of table more dense (like 5 tables per note) but this is going to be hard to do.. i wouldn't do it
also, the table interpolation algorithm with the slide and everything is going to be nasty, you'd better use an approximitation instead

[phono]

this might help, lots of samples of a real 303

http://www.dinsync.info/2010/02/tb-303- ... 0xb0x.html

[Acidfloor]

Thanks for the infos. Can you give my the weblink to the JAVA 303-like synth?

[antto]

nah, at that point (at the synth output) the VCO has passed thru a hole PILE of filters already (the VCF itself and lots of HPFs too, it's ugly..)
the waveform is so bent it's hard to tell what it was unless you are really familiar with how filters act on the phase
there is a big, fat thread at KVR, about 60 pages, of various things about approximating different aspects of the 303
there is another big fat thread about the filter, but so far it seems the filter is one of the easier things ;]
(now lots of people will argue about that, "the 303 is all about THE FILTER" .. nah, it isn't..)

[Acidfloor]

How do I w Wavetable from the Sampler?

[antto]

Thanks for the infos. Can you give my the weblink to the JAVA 303-like synth?

sure, but after dinner, i will have to find it somewhere in that big, fat thread i mentioned..

[antto]

How do I w Wavetable from the Sampler?

uhm, what?