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1080849 Posts in 71544 Topics- by 19060 Members - Latest Member: Areon Tomek
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Question: Is your 3rd partial F in tune?  (Voting closed: Jan 15, 2006, 05:19PM)
It is right in tune - 4 (17.4%)
It is sharp (I extend the slide to get it in tune) - 17 (73.9%)
It is flat - 2 (8.7%)
It is sharp on some of my horns but flat on others - 0 (0%)
Total Voters: 21

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timothy42b
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« Reply #20 on: Jun 03, 2016, 05:26PM »

In this sense, referring to the "3rd Partial F" in the context of a Bb instrument, would be referring to the specific sine wave whose frequency equates to F within the total spectrum of the fundamental note Bb. 

As if this is making it simpler  Pant

There is more than one meaning to the term partial, I'll grant you that.

But trombone players use the word very specifically, to refer to a note in a position.  That note contains a multitude of overtones, but the partial to us is the fundamental frequency of that note.  Yes, a fundamental Bb would have an F in the overtone series, but that isn't what we're talking about when we say 3rd partial F. 

Here's the important part.  If we play a Bb in 1st position and measure the frequency of the F, which is easy to do with modern equipment, and then repeat the experiment by playing 3rd partial F in that same exact position, they will not be the same frequency.
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Tim Richardson
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« Reply #21 on: Jun 03, 2016, 06:08PM »

Some trombone players might use the term very specifically and only for a single use. Many others toss it around interchangeably with overtone, harmonic, etc. They very well might be 'wrong' to the others, but the ambiguity is seemingly here to stay. On a side note, I find it becomes another motivation for true implementation of Scientific Pitch Notation, so that instrument-specific terminology can be removed from the conversation.

Here's the important part.  If we play a Bb in 1st position and measure the frequency of the F, which is easy to do with modern equipment, and then repeat the experiment by playing 3rd partial F in that same exact position, they will not be the same frequency.

Such may be the important part, but is it that simple? I will have to give it a run once I am back at the NMM with the BIAS toys. Will they certainly not be the same frequency? If you play a Bb, or better yet, generate one with a neutral driver, and then measure the ratios of its harmonic series, how do those ratios compare to the actual acoustic impedance nodes of the instrument? The note we call third partial F, and where we want it to fall musically, might very well be a different frequency from the overtone that results mathematically above any partial below it, but do the overtone and the partial actually differ? I've never considered that aspect.

As I see it, the problem with trying to make the comparison by asking any individual to play the two notes, is that their perception of the note and how they produce it via their embouchure is indiscriminately skewed by musical tendencies. Putting the slide in the same place is in no way any guarantee that they are playing anywhere near the center of either impedance node.
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MrPillow
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« Reply #22 on: Jun 03, 2016, 06:59PM »

For conversations sake, I went ahead and conducted a rudimentary test. I had a buddy of mine play a pedal Bb and third partial F with the slide all the way in. I instructed him to play as best he could straight down the center of the slot, not trying to adjust either way, simply matching where the horn resonated the best. I ran a FFT on both clips. Interestingly, the average frequency of F3 as an overtone of Bb1 and as the fundamental, was near enough the same - 175.97hz, or F3+13 cents in equal temperament.





Based on the average fundamental of the pedal Bb at 58.42hz (Bb1+4 cents), it is clear that neither the overtone or the third partial are aligning with the expected frequency ratio of the harmonic series (1901.95 cents for a pure 12th, 1908.98 cents for the acoustic 12th of that instrument), instead matching the "altered" harmonic series of the instrument itself. The third partial F appears to be sharper than expected by the same amount, whether it is functioning as a fundamental or an overtone. In hindsight it easily makes sense - you're not going to generate overtones anywhere other than the center of the horns natural impedance peaks.
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timothy42b
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« Reply #23 on: Jun 04, 2016, 05:44AM »

In hindsight it easily makes sense - you're not going to generate overtones anywhere other than the center of the horns natural impedance peaks.

Thank you for doing that.  That doesn't match results I've had so I'll have to try again.

But no, in hindsight it doesn't make sense.

The overtones of a steady note should be integral multiples.  That is a consequence of any driven system (as opposed to an impulsive system).  Driven systems respond at the driving frequency, not at their own natural frequencies.  We should not expect any system to generate overtones at its natural impedance peaks.  What we would expect is that the overtones would be strongest near those impedance peaks.

Lining up those impedance peaks is what makes horn design an art.  If you line them up near driven frequencies you get good response but lack of ability to color the tone, or should anyway. 
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Tim Richardson
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« Reply #24 on: Jun 04, 2016, 09:23AM »

Interesting. I tried the experiment again today with another player on a different trombone, and ended up with a third partial F that was roughly 6 cents sharper than F3 as an overtone of Bb1. The overtone F3 though, at any given instant, was still itself about 4 cents above than a pure 12th. Perhaps there is some influence not only on the placement of the impedance peaks, but their envelope as well. A horn with a wider impedance slot is more likely to have prominent overtones closer to the expected pure ratios?

If the impedance peaks have a very fast envelope, and are not well aligned with the pure ratios of the natural harmonic series, they will in effect diminish the presence of those non-aligning overtones in the sound?

So many factors at play, it's rather fun to ponder.
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« Reply #25 on: Jun 04, 2016, 09:36AM »

So, pull out?
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MrPillow
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« Reply #26 on: Jun 04, 2016, 02:36PM »

I think in the vast majority of circumstances, lowering the third partial F is going to serve you better than not lowering it. Old horns, weird horns, certain harmonies, can obscure the generalization.
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harrison.t.reed
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« Reply #27 on: Jun 04, 2016, 06:51PM »

So, pull out?

I always do  :D
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« Reply #28 on: Jun 05, 2016, 07:36AM »

So, pull out?

That's what sh* said!
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« Reply #29 on: Jun 05, 2016, 01:56PM »

Based on the average fundamental of the pedal Bb at 58.42hz (Bb1+4 cents), it is clear that neither the overtone or the third partial are aligning with the expected frequency ratio of the harmonic series

It's not surprising when you consider that, for pedal notes, the fundamental contributes practically nothing to the series.  Your graph shows that clearly, as the first significant peak is -33dB at ~175Hz, a whopping 30dB or so over the fundamental (about 32 times the amplitude) and about 24dB over the second harmonic.  To put it in perspective, 30dB is the kind of attenuation you'd expect from foam earplugs, or an exceptional pair of protective earmuffs.

Pedal B-flat sounds like a B-flat because it has a B-flat's overtones but, yeah, an average frequency in the neighborhood of the third harmonic sounds about right.
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MrPillow
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« Reply #30 on: Jun 05, 2016, 02:27PM »

So theoretically, for any note other than the pedal tones of a brass instrument, every sounding overtone should precisely fit the simple integer ratios of the pure harmonic series?
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BillO
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« Reply #31 on: Jun 05, 2016, 06:25PM »

It's not surprising when you consider that, for pedal notes, the fundamental contributes practically nothing to the series. 

I'm not too sure about this.  You can definitely hear the fundamental in pedal notes.  A first harmonic Bb and a pedal Bb do NOT sound the same, except as a note (Bb).  This result could have a lot to do with the recording equipment, the software and any filters that were applied (by whatever means, intended or otherwise).  I have made recordings on trombone pedal notes where the FT clearly shows the fundamental to be the dominant frequency in the harmonic series.

Of course I'm sure you'll all agree the physicist is wrong and has no clue. Don't know

Par for the course on TTF.


Ignore the above, as it appears to be incoherent rubbish.  BillO
« Last Edit: Jun 06, 2016, 06:00AM by BillO » Logged

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BillO
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« Reply #32 on: Jun 05, 2016, 06:33PM »

So theoretically, for any note other than the pedal tones of a brass instrument, every sounding overtone should precisely fit the simple integer ratios of the pure harmonic series?

What, for a real life trombone, or a cylindrical tube?

It would take a bit of real effort to come up with a usable theory for a real trombone - lips, mouthpiece, profile, material and all.  Most trombones would probably fit fairly well with that theory if it existed.

However, I would not expect them to comply exactly with a theory that suits the simple damped, driven harmonic oscillator (like a cylindrical tube driven with a zero impedance source), wherein every overtone should precisely fit the simple integer ratios of the pure harmonic series.
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timothy42b
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« Reply #33 on: Jun 06, 2016, 04:43AM »

I'm not too sure about this.  You can definitely hear the fundamental in pedal notes.  A first harmonic Bb and a pedal Bb do NOT sound the same, except as a note (Bb). 

Of course you can hear the fundamental, but it is constructed in your brain.

This is nothing new, this has been known for centuries. 

If your horn is conical enough you might get some fundamental content in a pedal note, but your ear will still hear it if it is completely filtered out and nonexistent.  The overtone series is sufficient to fool the ear without the pedal frequency.

Yes of course the first harmonic and the pedal sound different.  I think the ear can tell that the timbre changes without the fundamental even if it "hears" the pitch.  But also the overtone series is different.  The pedal Bb will have the 4th line F and ledger D, the first harmonic will not.   
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Tim Richardson
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« Reply #34 on: Jun 06, 2016, 05:59AM »

Of course you can hear the fundamental, but it is constructed in your brain.

This is nothing new, this has been known for centuries. 

If your horn is conical enough you might get some fundamental content in a pedal note, but your ear will still hear it if it is completely filtered out and nonexistent.  The overtone series is sufficient to fool the ear without the pedal frequency.

Yes of course the first harmonic and the pedal sound different.  I think the ear can tell that the timbre changes without the fundamental even if it "hears" the pitch.  But also the overtone series is different.  The pedal Bb will have the 4th line F and ledger D, the first harmonic will not.  

Okay. my bad.  I see eastcheap was talking about fundamental (lowest harmonic) tone in the production of the pedal Bb(1) and I was thinking something completely different.  The fundamental tone is the largest component in playing Bb(2), but my mind and fingers were not in sync.

Thanks for pointing it out.
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Eastcheap

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« Reply #35 on: Jun 08, 2016, 08:23PM »

It would take a bit of real effort to come up with a usable theory for a real trombone

There's nothing easy about a closed tube with a horn at both ends.

I believe clarinets and oboes are pretty good about playing by the rules.

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However, I would not expect them to comply exactly with a theory that suits the simple damped, driven harmonic oscillator

Probably best to think of the harmonic series as an ideal to which nature strives with varying degrees of success.  Wind instruments seem to get pretty close.
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