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Dirty-South Blues Harp forum: wail on! >
Question of Volume, Parts 2 and 3
Question of Volume, Parts 2 and 3
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WinslowYerxa
1125 posts
Apr 20, 2016
2:54 PM
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Per request, I've recorded the dynamic range of Draw 2, again on an A harp (this time a Filisko Marine Band).
Here's the audio recording:
Here's the complete waveform:
Here's the start of the waveform, magnified, with the very soft start of the note bookmarked:
Here's the waveform peak:
Looks like a dynamic range of about 44 dB (from about -50 db to about -6 db, vs. the slightly wider dynamic range of 49 db for Draw 4 that I previously posted. This is typical of the difference between these two note.
But wait, there's more.
Here's the spectral frequency display of the same waveform. Note how the fundamental note (the solid yellow horizontal line) gets brighter as the note gets louder. But so do all the overtone frequencies above it. So the tone color (distribution of volume among the overtones) doesn't appear to change as the note gets louder to due increased breath volume.
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Winslow
Check out my blog and other goodies at winslowyerxa.com
Harmonica For Dummies, Second Edition with tons of new stuff
Join us in 2016 for SPAH on the San Antonio River Walk!
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Killa_Hertz
1119 posts
Apr 20, 2016
3:10 PM
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What is the progtam you ve used here winslow?
Ive never seen the spectral display before. Thats very interesting. Ide be curious to record the same note played different ways. (Different mouth shapes and drawing in air in different ways) To see what changes exactly. What a note with "good tone" looks like vs a nasaly one, ect.
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WinslowYerxa
1126 posts
Apr 20, 2016
3:11 PM
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Here's part 3, where I investigate the effect of hand cupping on volume and overtone profile of a single sustained note.
This time I used a C harp and recorded Blow 6, simply because that's the easiest note for achieving and demonstrating this effect. Douglas Tate cultivated this effect throughout the range of a 3-octave C chromatic and used it to amplify his sound.
Here's the audio recording.
Here's the waveform, with the changes in cupping labeled. You can see that the volume changes with cupping. For every note there's a different optimal cup that will amplify the sound. I made my best efforts not to change breath column while playing this sustained note.
Here's the volume of the uncupped part at the beginning of the note, enlarged for clarity, at about -24 db:
Here's the volume of the optimally cupped part of the note, at about -14 dB:
So cupping optimally yielded a gain of about 10 dB in volume.
Here's the spectral display. You can see that with optimal cupping, the fundamental note (the yellow line just below 1Khz) gets brighter (louder), while the overtones get softer. So this gives the appearance of involving a redistribution of energy from the overtones to the fundamental - though you can see that the amplitude of the waveform also increases, so it's not just a psychological effect.
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Winslow
Check out my blog and other goodies at winslowyerxa.com
Harmonica For Dummies, Second Edition with tons of new stuff
Join us in 2016 for SPAH on the San Antonio River Walk!
Last Edited by WinslowYerxa on Apr 20, 2016 3:17 PM
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WinslowYerxa
1127 posts
Apr 20, 2016
3:13 PM
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@Killa_Hertz I'm using Adobe Audition. It gives you waveform display, spectral frequency display, and spectral pitch display, along with other tools, like phase (for mastering).
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Winslow
Check out my blog and other goodies at winslowyerxa.com
Harmonica For Dummies, Second Edition with tons of new stuff
Join us in 2016 for SPAH on the San Antonio River Walk!
Last Edited by WinslowYerxa on Apr 20, 2016 3:18 PM
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MindTheGap
1513 posts
Apr 22, 2016
2:33 AM
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Many thanks Winslow for doing this. If we all had the benefit of real-live teachers in the same room I don't think it'd be needed as ears would be enough. But those of use that don't, it's useful to have something concrete to aim at, especially around something as difficult to define as 'tone'.
A bit more analysis of the 2 draw soft/loud example is interesting. It's a bit hard to tell from the 'intensity spectrum' but a graph shows that the soft sound has lots of fundamental (sounds ringing, like a flute) and the loud sound has more volume in the 3rd harmonic, and some in the 2nd, giving it a particular timbre. Similar to the previous 4 draw example. Whereas the 'hand resonance' on 6B does boost just the fundamental, and in fact suppresses the higher harmonics.
The good thing is that we can experiment with this at home and actually measure against something. Different mouth shapes, vowel sounds and all that.
(If there's any ambiguity in how partials/harmonics/overtones are numbered see https://en.wikipedia.org/wiki/Harmonic)
2 draw, soft on the left, loud on the right.
Last Edited by MindTheGap on Apr 22, 2016 2:55 AM
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