Audacity Forum

DickN wrote:

Gale Andrews wrote: I was aware what you were talking about, which was why I said "I am not a Plot Spectrum expert"...

Sorry, I'd completely missed the point you were making there.

Not everyone finds it intuitive that the Meter/Waveform (dB) range affects the minimum Plot Spectrum amplitude. Would you like to vote for any of the Feature Requests about this:
http://wiki.audacityteam.org/wiki/Featu ... t_Spectrum ?



Gale

DickN wrote:On my Vista machine, I can adjust the horizontal size of the plot window and it's refreshed as I'm dragging the edge. On my XP laptop it doesn't refresh until I release the mouse button.

This is a Windows setting. Refresh on drag also works for me on Ubuntu 12.04 or OS X 10.7.3 (default settings).

On XP, go to the Control Panel > Display Properties > Appearance > Effects: Show window contents while dragging.

On Vista / 7, go to the Control Panel > Advanced System Settings: Performance > Visual Effects: Show window contents while dragging.

DickN wrote: Peaks that show up in a single pixel column vary in height, sometimes from oblivion to -85 or so. There's room for improvement here IMO - a peak completely between pixel columns should show up in the adjacent columns.

Screenshots may help. Are those separate or the same issue? I see a spike on a grid line overlaying the line.

And is this an issue only when horizontal dragging? I see the displayed height of a spike changing when you horizontal drag - is it meant to? The cursor readout of the peak doesn't usually change on drag in the case of a simple tone (even if the displayed height changes) but the peak readout does also change on drag with "complex" music.


Gale

DickN wrote:Test:
1-Generate 10s 1kHz sine 0.1 amplitude.
2-Select Spectrogram (lin or log, doesn't matter) in the TCP. The line shows up around 350 Hz!
3-Expand the vertical scale (click in the scale). The line jumps to 1000 Hz.

I tried this on both XP and Vista, same result.

I agree with Steve - On Win 7, Ubuntu 12.04 and OS X 10.7.3 I cannot reproduce the bug in linear Spectrogram, only in log f.



Gale

Gale Andrews wrote:This is a Windows setting. Refresh on drag also works for me on Ubuntu 12.04 or OS X 10.7.3 (default settings).

On XP, go to the Control Panel > Display Properties > Appearance > Effects: Show window contents while dragging.

On Vista / 7. go to the Control Panel > Advanced System Settings: Performance > Visual Effects: Show window contents while dragging.

Thanks! That helps a lot.

Gale Andrews wrote:I agree with Steve - On Win 7, Ubuntu 12.04 and OS X 10.7.3 I cannot reproduce the bug in linear Spectrogram, only in log f.

My mistake. Just tried it again on XP laptop and it only happens with log scale.

Gale Andrews wrote:

DickN wrote: Peaks that show up in a single pixel column vary in height, sometimes from oblivion to -85 or so. There's room for improvement here IMO - a peak completely between pixel columns should show up in the adjacent columns.

Screenshots may help. Are those separate or the same issue? I see a spike on a grid line overlaying the line.

I think they're separate issues. When I can hear 480 Hz but can't see it on the plot even with "size" below 4096 and using the Blackman-Harris window, I don't think the spike is hiding between pixel columns. That's a problem mainly above 1 kHz although you can see the effects even at lower frequencies.

Gale Andrews wrote:And is this an issue only when horizontal dragging? I see the displayed height of a spike changing when you horizontal drag - is it meant to? The cursor readout of the peak doesn't usually change on drag in the case of a simple tone (even if the displayed height changes) but the peak readout does also change on drag with "complex" music.

When I drag an edge (resizing the plot window), with a complex spectrogram the cursor stays in about the same place on the screen while the coordinate plane stretches/shrinks behind it, thus both frequency and amplitude readouts change. With a single tone, it only finds the one peak and so follows the plot at least for a little ways, but not very far. If you watch the "cursor" (rather than the "peak") coordinates, you'll see them changing even with a sinewave. I think the cursor should stay at a fixed frequency while the plot is being resized, but that's not a major issue at least for me.

DickN wrote:

Gale Andrews wrote:I agree with Steve - On Win 7, Ubuntu 12.04 and OS X 10.7.3 I cannot reproduce the bug in linear Spectrogram, only in log f.

My mistake. Just tried it again on XP laptop and it only happens with log scale.

I opened a bug for it http://bugzilla.audacityteam.org/show_bug.cgi?id=525 . Thanks for reporting it.

DickN wrote:

Gale Andrews wrote: Peaks that show up in a single pixel column vary in height, sometimes from oblivion to -85 or so. There's room for improvement here IMO - a peak completely between pixel columns should show up in the adjacent columns.
Screenshots may help. Are those separate or the same issue? I see a spike on a grid line overlaying the line.

I think they're separate issues. When I can hear 480 Hz but can't see it on the plot even with "size" below 4096 and using the Blackman-Harris window, I don't think the spike is hiding between pixel columns. That's a problem mainly above 1 kHz although you can see the effects even at lower frequencies.

DickN wrote:

Gale Andrews wrote:And is this an issue only when horizontal dragging? I see the displayed height of a spike changing when you horizontal drag - is it meant to? The cursor readout of the peak doesn't usually change on drag in the case of a simple tone (even if the displayed height changes) but the peak readout does also change on drag with "complex" music.

When I drag an edge (resizing the plot window), with a complex spectrogram the cursor stays in about the same place on the screen while the coordinate plane stretches/shrinks behind it, thus both frequency and amplitude readouts change. With a single tone, it only finds the one peak and so follows the plot at least for a little ways, but not very far. If you watch the "cursor" (rather than the "peak") coordinates, you'll see them changing even with a sinewave. I think the cursor should stay at a fixed frequency while the plot is being resized, but that's not a major issue at least for me.

I understand the amplitude of the plot will change when using different sizes. Steve may know more about whether horizontal drag should change the peak heights but I suppose yes. There does seem to be a problem with the displayed height of the thinnest peaks not matching the peak in the readout. This is very easily seen if horizontally dragging a tone because of the jumps in the displayed height of the peak are very obvious.

I can see that the cursor obliterates a thin spike when over it, which is not so bad if you can trust the readout (which I assume we can). Do you really think the peak should appear either side of the cursor when the cursor obliterates it? Are there better solutions?


Gale

Gale Andrews wrote: Not everyone finds it intuitive that the Meter/Waveform (dB) range affects the minimum Plot Spectrum amplitude. Would you like to vote for any of the Feature Requests about this:
http://wiki.audacityteam.org/wiki/Featu ... t_Spectrum ?

I like these from the Plot Spectrum heading (I'm putting each in quotes, but not always copying everything):

"Zoomable/pannable frequency axis (4 votes)"

"More distinctive cursor line (2 votes) bolder, or different colour to grid lines"

"Multiple spectra window: (6 votes) Plot multiple spectra for different tracks/regions in the same project... Currently different spectra must be in different projects."

"Text box input for lowest visible level (4 votes)"

(single-vote item):
"I like the display of the frequency at the cursor point as a musical pitch-class/octave. Could you add a cents qualifier to the musical pitch discription. For example if the cursor is located at 443 Hz, that would be the pitch A4, but slightly sharper, so it would be nice to have the cursor display for that frequency read: A4+12, since it would be 12 cents sharp of A4 in equal temperament at A4 = 440 Hz. If the frequency were 437, then the cursor display could read A4-12, which would stand for A4 minus 12 cents."

[Other analytical/statistical ability]

[Spectrograms]

"Erase Tool to remove pieces of spectrum: (4 votes)
e.g. removing harmonics or 'mouth noise' from vocals (saliva clicks, ...)"

I would add Use Case: Removing a brief sound with varying pitch (e.g., a baby's cry).

"Crosshair as in Plot Spectrum (2 votes) which enables on-screen measurement of the frequency and dB level."

There are several ideas on the page and linked pages that would be off-topic here which I'd like to vote for, and one I'd like to add onto. I read the instructions but can't find the "edit" links. Is editing allowed by just anybody? Is there a wizard to help control the format?

-DickN

Gale Andrews wrote:I can see that the cursor obliterates a thin spike when over it, which is not so bad if you can trust the readout (which I assume we can). Do you really think the peak should appear either side of the cursor when the cursor obliterates it? Are there better solutions?

I wouldn't want the spike to change shape when the cursor is over it. I'm accustomed to having it hide behind the cursor, but if the cursor were a different color (an improvement anyway since in a screen shot it looks just like a grid line) and had some transparency the spike and the cursor could be superimposed and both still be visible. (see my previous post - someone already requested "more distinctive cursor line")
- DickN

Thanks, DickN. I added your votes and comments.

DickN wrote:There are several ideas on the page and linked pages that would be off-topic here which I'd like to vote for, and one I'd like to add onto. I read the instructions but can't find the "edit" links. Is editing allowed by just anybody?

I'll have to give you a Wiki account if you would like to edit the page. Or you can PM me with what you want to vote for and append to.

DickN wrote:Is there a wizard to help control the format?

Only the human ones that can sort out all the nested lists on that page.



Gale

Gale Andrews wrote:There does seem to be a problem with the displayed height of the thinnest peaks not matching the peak in the readout. This is very easily seen if horizontally dragging a tone because of the jumps in the displayed height of the peak are very obvious.
Gale

I note that for frequencies above around 5 KHz (for 44,100 SPS), switching to Linear frequency axis somewhat ameliorates these effects.

- DickN

I moved this here from the FR section

Peter.