[LAD] Portable user interfaces for LV2 plugins
gheskett at wdtv.com
Thu Mar 3 02:33:43 UTC 2011
On Wednesday, March 02, 2011 09:15:32 pm Fons Adriaensen did opine:
> On Thu, Mar 03, 2011 at 12:17:40AM +0100, Stefano D'Angelo wrote:
> > Does point #1 mean we basically may want visualization that expresses
> > only a few properties of a certain waveform?
> Yes. Waveforms displays are completely useless for normal
> audio engineering. You may need them for technical purposes,
> when doing maintenance or testing. But there it ends.
> Interesting properties are peak level, RMS level, spectrum,
> etc. and their short term history.
> A waveform just contains too much information that is in
> almost all cases irrelevant. It's easy to find waveforms
> that look completely different but sound just the same.
> Or some that look almost the same but sound very different.
I beg to disagree with the premise that the waveform is useless. I have
had a scope probe in one hand for 60 years now, and there is nothing that
comes close to finding that slightly edgy sound that just isn't quite right
like a good look at the waveform when you have a known test signal.
Clipping is easier to see, crossover distortion is easily seen by the
trained eye, and even slew rate limits can be made to stand out plain as
Note however that I am not referring to a digitized waveform which has its
own set of problems unless the sampling frequency is 100's of times faster
than the signal being sampled, I am referring to the raw analog signal
itself. Digitize crap,and you still have crap even if the digital sample
is quite high and the A-D is totally monotonic. Consumer stuff rarely is
either wide range linear, nor monotonic beyond 13 or 14 bits in a 16 bit
system. Even 24 bit stuff probably falls face first in its oatmeal at 20
Yes, you can see the results of all those distortions by doing an FFT on
the digital signal, but unless one is intimately familiar with the FFT
display, it can't tell you the real problem is crossover related so you
only guess, or find someone who can tell you whats wrong, and chances are,
he will use an analog scope to find and point it out.
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