Talk:Audio Track Dropdown Menu

Copied from main page on May 1 2011
Umm .. this spectrum plot does not seem to exist. Just as well, as it would just confuse things. - Bill You can view a sound in Audacity in another way than over time. Here is the "Audacity" word again as a spectrum plot, showing the relative energy (dB) of each frequency in the entire word. Had the voice been female, the plot would have shown its higher frequencies.

Pitch (EAC)
Highlights the contour of the fundamental frequency (musical pitch) of the audio, using the Enhanced Autocorrelation (EAC) algorithm.

The EAC Algorithm was developed to produce a mathematical representation of the changes of pitch in a piece of audio. The aim was to allow automated comparison of sound files so that two versions of the same tune could be recognized as being similar, even if played in different keys, or on different instruments.

When using Pitch view, go to Spectrograms Preferences and make sure that "Frequency Gain" is set to 0 or 1. Any other setting will make the Pitch view unusable.


 * Here is the spoken word "Audacity" in Pitch view:
 * [[Image:SndAudacityPitch.png|The word 'Audacity' as a plot of pitch.]]


 * Here is a two-octave scale from middle C played on the piano.
 * [[Image:PianoScale.png|Pitch view of a two-octave scale from middle C]]

The above image needs explanatory text. The below image should probably be incorporated or even used instead as it shows different colors (these need explaining). I have no idea how to explain Pitch View or any of these images - Bill I agree the images above need updating. 1.3.9 displays them in multi-color. Maybe an image of a two-octave scale played on the piano, with a short description, would give a better sense of the relationship between the picture and the sound. I can try to upload something. I believe that blue alone represents frequency components below 1kHz and blue and red combined represents components above 1kHz, but I haven't got a definitive answer. - Paraic Bill: I think the piano scale does the trick as far as demonstrating what pitch view does. It appears the vertical scale is pitch and the colors represent intensity? Paraic The vertical scale is pitch. The colors do represent intensity, but the higher-intensity colors appear only in the range of 1kHz and upwards. This must be a consequence of the way the algorithm works. It takes 10mS slices of the audio and splits each slice into components above 1kHz and below. It half-wave rectifies and low-pass filters the high-frequency component, then performs an autocorrelation function separately on each component, to try to extract the fundamental frequency of each, and finally combines the two components again. I imagine that the lower frequencies, which have little or no component above 1kHz, must have, relatively, less energy after the process, and this may explain the lack of red color in this area. Is such a description of the algorithm useful, or necessary, for the manual?


 * [[Image:Track pitch.jpg|an example of a Pitch view of a track]]

Here is a chirp from 200 Hz to 8 kHz in Pitch view:
 * [[Image:SndAudioPitchChirp.png|Chirp as a plot of pitch.]]

Older Archives
Ed: welcome to the "quick text" debate. Have a look at Talk:File Menu. "Quick text" is what you have created here. To summarize, the problem with quick text is that it repeats information presented in the detailed section below. But see the debate on the File Menu talk page. A decision was made to abandon quick text for 2.0 and revisit it later to see if we could make it work. - Bill

If possible, an image including the timeline would make the point even clearer (but not essential). However the zoomed in image is too wide. I think it could be the same length as the others while still getting the point across -  Gale Timeline doesn't always make the units clear - and having just redone them I don't fancy redoing the complete set again 'for comparison purposes', so a shorter chirp, yes, but probably without timeline.- James OK, unless you think we can get away with the timeline just on the waveform images. Or we can just say how long the sound on the second image is - it probably is not obvious how short it is. Also you could probably resize the overlong image if you don't want to recapture it. Track Panel would be less wide but it would be obvious why.- Gale Will recapture, with timeline. Done.

Perhaps we should be using spectrogram and spectrum to differentiate between the two displays, and make a change in Audacity wording too? (not a high priority). Not sure. I think the point about the spectrum plot might be to remark if it's made by a male or female voice (I presume that plot is yourself) and to explain what it might have looked like if a female voice had spoken it - Gale We're already saying a bit more than we strictly need to for a reference on the features of the Audacity GUI. It's a good idea, but I think it belongs on a tutorial page, where we can show beat frequencies, clicks, hums, noise, spectrum of a square wave, flute vs guitar etc etc. Yes it's my voice.-James If we ever produce such a tutorial, we can link to it here. Meantime, now we've gone this far, I've said it in about five more words than we had before. I also noticed we're missing what seems to me essential (what the waveform scales mean, which is not described elsewhere yet?). I've tried to work this in whilst taking only a few more words. This probably means we can now restrict Timeline to discussing the timeline. This makes more sense, and we can probably rename it to Timeline. To me the current balance on this page is about right - I readily agreed with your idea of the example of the chirp and word here. Having only a strict "Reference" in the old manual was not popular - people wanted more explanation about what menu and Gui items meant and did and why, as well as the full blown tutorials on a complete process - see the Help list and old forum comments. -Gale Agree strongly. This has become a very good page. I'll update the table to the file-menu look later. Done.