[sdiy] saw vs ramp, audible?

[Mattias Rickardsson]

There are nonlinearities in our hearing that can make the polarity matter,
even if it "shouldn't". I also seem to recall reading that on increasingly
lower-frequency sawtooths there is an increased difference between the
polarities - so it matters if the edges are "knocking" inwards or "pulling"
outwards. At low rates, those waveform shapes turn into discrete events,
and I'm quite sure that Don's interesting screwed-phase sawtooth versions
would sound quite different!

Our hearing isn't such an ideal spectrum analyzer that we might think,
especially when taking both ears into account. Then unexpectedly tiny
timing or phase differences can be detected, non-spectral information that
is used in our psychoacoustics.

I don't have any pointers to information sources right now, but I'd gladly
get some hints since it's a very interesting field!

Regarding your interesting note about perceiving slightly different pitch,
Jonatan - could it be that one was perceived louder than the other? The
"acoustic reflex" seems to make louder synth tones bend away slightly in
pitch.

(Btw listening to raw edgy waveforms in headphones is quite nasty... it's
like other strange audio artifacts pop up in your brain. Why do we still
listen to those waveforms, why not have them pink-filtered or something) :-)

/mr


Den sön 8 dec. 2024 23:16Jonatan Liljedahl <lijon at kymatica.com> skrev:

> I tried this some year ago, and it was an audible difference, which
> surprised me a lot. Now I don’t remember if the difference was heard in
> headphones but not speakers, or the other way around. And, at least my
> brain perceives a slight pitch change between saw and ramp!
>
> /Jonatan
> http://kymatica.com
>
>
> sön 8 dec. 2024 kl. 23:00 skrev Chris McDowell via Synth-diy <
> synth-diy at synth-diy.org>:
>
>> Hah right, I should specify I mean theoretically! It's clear to me that a
>> speaker or room or overlaid waveform could reveal which tooth we were
>> dealing with.
>>
>> Thanks for the responses. I am happy to upend my understanding of
>> harmonics whenever necessary, but glad I don't have to today.
>>
>> this came up because I was thinking about someone's post here or on their
>> blog about shifting the phase of harmonics and how that can yield wave
>> forms that look very different, but sound the same. I googled "phase shift
>> audible waveform" or something like that to try to find the article. maybe
>> someone remembers where that is or wrote it themselves :)
>>
>> Cheers,
>> Chris
>>
>> > On Dec 8, 2024, at 3:41 PM, Tom Wiltshire <tom at electricdruid.net>
>> wrote:
>> >
>> > +1 What Richie said.
>> >
>> > You can organise a situation in which the difference will be
>> significant, but it involves doing something extra.
>> >
>> > The raw waveforms on their own? No, you can't tell. This is easy to
>> check by building an inverting buffer and then A/B testing between the
>> input and output of the buffer.
>> >
>> >> On 8 Dec 2024, at 21:15, Chris McDowell via Synth-diy <
>> synth-diy at synth-diy.org> wrote:
>> >>
>> >> Falling saw vs a rising ramp, is the difference audible? What is the
>> definitive answer? I have believed for years that the difference is not
>> audible, that maximum disconinuity followed by minimum discontinuity is
>> what a saw or ramp is, and inverted but otherwise identical waveforms sound
>> identical. I came across a wealth of traffic online today arguing against
>> that. I'm super skeptical. Folks' arguments were passionate but not
>> complete in a way that could convince me. What is the real deal here?
>> >>
>> >> Cheers,
>> >> Chris McDowell
>> >> ________________________________________________________
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