Am 09.04.2012 16:24, schrieb Ross Bencina:
Hello Julian,
Assuming all variables are integers, if phase doesn't divide TABLESIZE
then you will get a different waveform amplutude for adjacent cycles.
Perhaps that's what you're seeing?
oh sorry, i forgot to mention.
the phase accumulator is a
If you don't interpolate the wavetable then you may be simply getting
some aliasing problems. Every Nth cycle of the generated waveform will
be one sample shorter than the others, and that will sound like a
click. Try setting your phaseInc to an integer value. Also, somewhere
along the analog
okay i tried your suggestion.
reducing the wavetable amplitude to 0.8 instead of 1 changed nothing.
but it isn't a clipping problem.
no nonlinea frequencies are added.
The signal only consists of the right harmonic overtones
setting the phase increment to an integer value solves the problem.
but
Interesting...my STM32F4DISCOVERY just arrive Friday...intending to make a
wavetable oscillator on it, fist thing...
Are you writing the wavetable to a buffer, then pulling from that at the sample
rate? if so, what size?
On Apr 9, 2012, at 6:28 AM, Julian Schmidt wrote:
Hello all,
I'm
i hadn't heard of this dev board before. at
http://www.st.com/internet/evalboard/product/252419.jsp it says that the
single unit prices is US$14.9 . is that right? that's nearly free.
where do the software tools (the compiler/linker/loader/etc) come from?
regarding wavetable indexing,
at the moment I use a sample based I2S interrupt (44.1 16-bit stereo).
the alternative would be a direct DMA to feed the codec (all buffersizes
up to 0x are supported).
but for the moment i decided on latency free sample based calculations.
I've also got a state variable filter running on
Yes, that's the price. I have like 3 of them before someone gets wise :)
Paul S.
-Original Message-
From: music-dsp-boun...@music.columbia.edu
[mailto:music-dsp-boun...@music.columbia.edu] On Behalf Of robert
bristow-johnson
Sent: Monday, April 09, 2012 12:17 PM
To:
Am 09.04.2012 19:16, schrieb robert bristow-johnson:
i hadn't heard of this dev board before. at
http://www.st.com/internet/evalboard/product/252419.jsp it says that
the single unit prices is US$14.9 . is that right? that's nearly free.
yes exactly. it's cheaper than buying the cortex m4
On 09/04/2012, Julian Schmidt julian_schm...@chipmusik.de wrote:
yes exactly. it's cheaper than buying the cortex m4 chip alone.
and you get a stereo codec (with limiter and equalizer)
Stupid question, but the limiter is turned off, isn't it...?
--
dupswapdrop -- the music-dsp mailing list and
On Apr 9, 2012, at 10:16 AM, robert bristow-johnson wrote:
i hadn't heard of this dev board before. at
http://www.st.com/internet/evalboard/product/252419.jsp it says that the
single unit prices is US$14.9 . is that right? that's nearly free.
Yes, from Mouser. With tax and UPS ground, it
On Mon, Apr 9, 2012 at 7:17 PM, Julian Schmidt
julian_schm...@chipmusik.de wrote:
setting the phase increment to an integer value solves the problem.
[...]
adding linear or cubic interpolation makes it a little better, but the
pulsing is still very audible.
[...]
The nearer i get to an
On 04/09/2012 10:16 AM, robert bristow-johnson wrote:
i hadn't heard of this dev board before. at
http://www.st.com/internet/evalboard/product/252419.jsp it says that the
single unit prices is US$14.9 . is that right? that's nearly free.
where do the software tools (the
I think you win! ;)
first i tried switching to integer phase accumulators like RBJ suggested.
It sounded exacly the same.
I really think it is an aliasing problem.
but not due to the wrong wavetable content, but due to a cheap audio
codec with poor filters.
I toyed around with the mip
here are some screenshots...
the beating bell shape on 440Hz sinus with 84 harmonics
http://i.imgur.com/B4s0M.png
a simple sine table 220Hz
http://i.imgur.com/hPKj1.png
julian
Am 09.04.2012 22:32, schrieb Julian Schmidt:
I think you win! ;)
first i tried switching to integer phase
On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt
julian_schm...@chipmusik.de wrote:
I really think it is an aliasing problem.
but not due to the wrong wavetable content, but due to a cheap audio codec
with poor filters.
[...]
even when i output a single 440hz sine i get harmonics starting at
Am 09.04.2012 23:22, schrieb Olli Niemitalo:
On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt
julian_schm...@chipmusik.de wrote:
I really think it is an aliasing problem.
but not due to the wrong wavetable content, but due to a cheap audio codec
with poor filters.
[...]
even when i output a
On Tue, Apr 10, 2012 at 12:25 AM, Julian Schmidt
julian_schm...@chipmusik.de wrote:
Am 09.04.2012 23:22, schrieb Olli Niemitalo:
On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt
julian_schm...@chipmusik.de wrote:
I really think it is an aliasing problem.
but not due to the wrong wavetable
i dunno why, but i can no longer reply to the thread that Julian
started. if this post gets to the list, then i think there is some
damaged header or something. this has happened to me before and it only
happens with this mailing list.
after hitting Send, Thunderbird tries sending it and
Robert,
I haven't heard of anything like that. It's unlikely that it's the list
software complaining, sounds more like the server itself. And since
others are replying to the thread it's probable that the header damage
(if that's the problem) is happening on your machine rather than on the
Just a test reply to see if I have the same problem Robert's having...
douglas
On 4/9/12 10:43 AM, Julian Schmidt wrote:
Am 09.04.2012 16:24, schrieb Ross Bencina:
Hello Julian,
Assuming all variables are integers, if phase doesn't divide TABLESIZE
then you will get a different waveform
testing 1,2,3...
this is identical to a previous message (that would not get past my
SMTP) with this sentence added and the subject header changed..
On 4/9/12 5:25 PM, Julian Schmidt wrote:
Am 09.04.2012 23:22, schrieb Olli Niemitalo:
On Mon, Apr 9, 2012 at 11:32 PM, Julian Schmidt
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