This phase thing

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Nick
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#16 Re: This phase thing

Post by Nick »

Back being a Luddite - what DO YOU expect this to show us. Now you have made it disconnected tones I don't see how it can show anything as there is no transition. Still confused as to the point, when you can hear it so clearly with music.
What it shows me is that I can clearly hear the difference when only changing the phase of a single simulated violin note by a relatively small amount.

I expected it to show ne if it was easy to show how much phase mattered, and thats what it did show me.

What does interest me is that if I was asked I would say the difference was of frequency, one sounding slight flat WRT the other. I am interested that a small phase change will have that effect. Its also interesting that others cant hear the difference.

Here is a lower frequency version of the same

http://www.lurcher.org/nick/ALT30-100.WAV

Actually, the difference in tone is very similar to me to the tone a bowed instrument makes with the two directions of bow travel.
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#17 Re: This phase thing

Post by pre65 »

The second tone now seems a tiny tad less loud, or perhaps less sharp.
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#18 Re: This phase thing

Post by Scottmoose »

Probably going to depend on what it's played through too Nick, re whether some can hear a difference & some can't -you know what some PC speakers etc. are like.

One interesting thought: up to about 700Hz ITD dominates our ability to process phase & localise sound. Above about 1.4KHz IAD dominates how we do that. In the band between, our ability to localise sound & process phase related information isn't so good.

*Edit: Tried it a few times now. Agreed, possibly sounds a touch flatter, but hard to tell as I've not put it through my main setup as I'm still down with lurgy.
Last edited by Scottmoose on Sat Apr 08, 2017 3:30 pm, edited 1 time in total.
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#19 Re: This phase thing

Post by andrew Ivimey »

You are going to remind me what ITD and IAD are, aren't you, please?
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#20 Re: This phase thing

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I tried the original 3 sec one again and there is a minute difference, but easy to miss.

Did I hear it because I knew what I was expecting ?
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#21 Re: This phase thing

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Scottmoose wrote: Sat Apr 08, 2017 3:21 pm Probably going to depend on what it's played through too Nick, re whether some can hear a difference & some can't -you know what some PC speakers etc. are like.

*Edit: Tried it a few times now. Agreed, possibly sounds a touch flatter, but hard to tell as I've not put it through my main setup as I'm still down with lurgy.

One interesting thought: up to about 700Hz ITD dominates our ability to process phase & localise sound. Above about 1.4KHz IAD dominates how we do that. In the band between, our ability to localise sound & process phase related information isn't so good.
But the point being you (or some) can hear a difference. In a graph of frequency against amplitude the two waves are identical. A FFT of the harmonics if it only shows amplitude will show them as identical.
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#22 Re: This phase thing

Post by pre65 »

ITD = Interaural time difference ?

https://en.wikipedia.org/wiki/Interaura ... difference

IAD = interaural amplitude difference
Last edited by pre65 on Sat Apr 08, 2017 3:39 pm, edited 1 time in total.
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#23 Re: This phase thing

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I defer to yourself, obviously Andrew, but if lurgy-limited memory recalls correctly, ITD = interaural time difference & IAD = interaural amplitude difference.
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#24 Re: This phase thing

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pre65 wrote: Sat Apr 08, 2017 3:31 pm I tried the original 3 sec one again and there is a minute difference, but easy to miss.

Did I hear it because I knew what I was expecting ?
Ok, only one of the 10 is different, which one is it?

http://www.lurcher.org/nick/ALT30-100-Q.WAV
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#25 Re: This phase thing

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Scottmoose wrote: Sat Apr 08, 2017 3:36 pm I defer to yourself, obviously Andrew, but if lurgy-limited memory recalls correctly, ITD = interaural time difference & IAD = interaural amplitude difference.
But this is a mono signal, not trying to test localisation. The original question I am trying to examine is how the relative phase of harmonics alters our perception of a sounds tone.
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#26 Re: This phase thing

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Nick wrote: Sat Apr 08, 2017 3:39 pm
pre65 wrote: Sat Apr 08, 2017 3:31 pm I tried the original 3 sec one again and there is a minute difference, but easy to miss.

Did I hear it because I knew what I was expecting ?
Ok, only one of the 10 is different, which one is it?

http://www.lurcher.org/nick/ALT30-100-Q.WAV
The eighth one I think.
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#27 Re: This phase thing

Post by Nick »

So you can hear it even though you didnt know what you were expecting.
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#28 Re: This phase thing

Post by Dr Bunsen Honeydew »

I am just listening on my laptop I must get the connection to dac put back.

I still say it is better doing it on speakers with music. You will *really* hear it then.
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#29 Re: This phase thing

Post by Dr Bunsen Honeydew »

Nick wrote: Sat Apr 08, 2017 3:39 pm
pre65 wrote: Sat Apr 08, 2017 3:31 pm I tried the original 3 sec one again and there is a minute difference, but easy to miss.

Did I hear it because I knew what I was expecting ?
Ok, only one of the 10 is different, which one is it?

http://www.lurcher.org/nick/ALT30-100-Q.WAV
Eight and nine sound like less level with eight being more so. That is all I detect on my laptop.
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#30 Re: This phase thing

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Eight being the one that has the shifted phase. It does to me show that with a bit of effort I can convince myself that two identical tones are different because I heard one of them first then the second. There is no real magic or point to this test other than to show just shifting the phase of harmonics of a simple tone can be heard. That suggest to me that more complex music would be at least as affected by phase differences across the frequency range. It also shows the actual difference heard is not obvious and sounds like amplitude and or frequency shifts.
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