Harmonic series and triggers

Discussion in 'The Rehearsal Room' started by GER, Mar 1, 2019.

  1. GER

    GER Active Member

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    Got a feeling this may get too complicated but I'm going to ask anyway :)
    If for example one plays a middle D on 1st valve this is naturally slightly flat as it's a 5th in the harmonic series, to correct this (if needed) you could play the D on 1 and 3 valves, as this is a 6th in the Harmonic so slightly sharp, however the general rule for playing valves 1 and 3 (on cornet) is use 3rd valve trigger, but if you do that surely it negates the 'sharpness' of the note, putting you back to square one. I know the simple answer is listen, but what I am interested in is am I right in theory or am I missing something and looking at it too simplistically?
     
  2. GJG

    GJG Well-Known Member

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    Because the 6th harmonic is naturally sharp, and because 1+3 on a non-compensating instrument without triggers is also naturally sharp, then to play a 4th-line 'D' on 1+3 will theoretically result in the note being "doubly" sharp; if I elected to play that note on 1+3 I would normally expect to have to flatten it slightly with one of the triggers.
    The essential point being that it's not just low 'D' on 1+3 that's sharp, but the whole harmonic series on 1+3.
     
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  3. GER

    GER Active Member

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    Many thanks-the answer was a lot simpler than I thought it would be, never thought about the 'doubling up' effect.
     
  4. 2nd tenor

    2nd tenor Well-Known Member

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    @ GER, I’m really glad that you posted on this topic as it was in my mind too. I know that Moomin has a lot of expertise on the subject so perhaps he’ll chip in with some comments on harmonics and valve combinations. IIRC G above the stave is normally sharp when played open but 1+2 gives a better result.

    The D note that you mention is sometimes played using the 4th valve on a Tuba, as an improvement to intonation.
     
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  5. Tom-King

    Tom-King Well-Known Member

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    It depends on the instrument...
    The natural tendency is for that note to want to tend sharp (along with the E below it tending to be flat), though some instrument makes/models are much worse for it than others.

    To compound it, poor air support will often push it further sharp.

    Playing it 1+2 will flatten it (using the open Bb, a flat harmonic) and sometimes this is useful to know, along with 2+3 for F# and 1+3 for F.

    That said...
    There's arguments for not simply using 1+2 automatically (all the time), not least that you don't want to be using so-called "false-fingering" as a crutch for deficiencies in technique.
    If your instrument is particularly bad, of course this is different (at any rate, most instruments that require this will also require 1+2 E and 1+3 D to raise them up).


    Although on a compensating instrument it shouldn't really make a difference.
     
  6. MoominDave

    MoominDave Well-Known Member

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    It depends on the individual instrument, of course - but the theoretical tuning of these two harmonics is as follows:
    5th partial (E on open): 14 cents flat (where 1 cent = 1/100 semitone)
    6th partial (G on open): 2 cents sharp
    Now, we all know instruments that don't follow this anywhere near exactly - the old G trombones even have the opposite tendency on these two partials, and the shaaaarp top G on Sovereign euphs blows any theory out of the water - but this is the basis position, and often instruments don't disobey it too badly. The salient point is that the 5th partial is much flatter than the 6th is sharp in an ideal world - 7 times as much. So we can pretty much leave the 6th partial sharpness out of our thinking unless the instrument in question suffers on the subject.

    Now, combination of 1+3. You have various tuning options with the third valve to try to fiddle the general effect as best into tune on average as may be:
    If you tune it to an in tune A on 3, then 1+3 goes 30 cents sharp;
    If you tune it to an in tune Ab on 2+3, then 1+3 goes 16 cents sharp;
    You can tune it so that 1+3 is in tune, but then your Ab on 2+3 is 16 cents flat. Splitting the difference between an in tune Ab and G on an untriggered instrument is not a bad strategy. However, we're talking about a triggered instrument, so I would suggest that tuning 2+3 in tune is likely to be the best route all round.

    In this case the options for that D are:
    5th partial, 1st valve - 14 cents flat
    6th partial, 1+3 - 2+16 = 18 cents sharp
    So it goes a little sharper than it was flat, but you can easily bring it flatter with the trigger - the ideal tuning is identical to the octave below, D on 1+3 at the bottom of the staff. It isn't uncommon for players to use the 6th partial rather than the 5th when tuning is problematic in this circumstance.
     
  7. MoominDave

    MoominDave Well-Known Member

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    I would advise a lot of caution in employing the 7th partial (which is what G on 1+2 is). While it may work on an individual instrument/player combo tolerably enough not to offend the ear, this fingering is whackingly flat - 20 cents
     
    Last edited: Mar 1, 2019
  8. Tom-King

    Tom-King Well-Known Member

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    Indeed.

    Yes it works, sometimes it's useful to know, but it certainly shouldn't be a routine choice.

    Problem is a lot of players introduce too much tension up high, start going sharp and because we use these notes all the time in band playing people find ways to "make good" as much as possible... And often, this is good enough and "it works" so is left alone.

    (IMHO!)
     
  9. 2nd tenor

    2nd tenor Well-Known Member

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    I puzzled about that for a while ‘cause I couldn’t grasp what you were saying, then I wondered if perhaps you had misunderstood my earlier comment. For that D a four valve instrument could use the 4th valve instead of 1+3 rather than as well as. Compensation on a four valve instrument only works once the fourth valve is depressed, I cannot see much point to pressing 4, 3 & 1 together.
     
  10. 2nd tenor

    2nd tenor Well-Known Member

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    Of course you’re absolutely correct, I just find that some instruments vary and then try to have some fall-back techniques to help me work around things.
     
  11. Tom-King

    Tom-King Well-Known Member

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  12. 2nd tenor

    2nd tenor Well-Known Member

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    Yes, interesting reading. I think that as far as Tubas are concerned David Werden is amongst the most knowledgeable people on the World Wide Web.

    Perhaps this quote from David’s text (on the site you direct us to) might be helpful:
    “ The 4th valve tubing routes back through the first 3 valves so that when the 4th valve is used in combination with any other(s), air can automatically be detoured through extra compensating loops.

    Progressing downward from the open horn, the first five fingerings (2, 1, 3, 23, and 4) don't involve the compensating system as their intonation is satisfactory. However, the compensating loops are used for the next six fingerings (24, 14, 34, 234, 134, and 1234), since their pitch would otherwise vary from uncomfortable to unusable. ”

    David’s comments (as directly above) above appear to confirm the correctness of my statement in response #9 above. I said: “Compensation on a four valve instrument only works once the fourth valve is depressed”.
     
    Last edited: Mar 2, 2019
  13. 2nd tenor

    2nd tenor Well-Known Member

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    Agreed, as in my other response somewhere in the chain above. Dave, I just wonder if there is somewhere a chart of standard and alternative fingerings that tells the user how sharp or flat any particular combination is likely to be (variations between particular instruments excepted).
     
  14. Tom-King

    Tom-King Well-Known Member

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    Think you're right...

    I misread/misunderstood - if nothing else, I thought the point was to fix intonation (as it does on a 3v compensator) rather than to make the 4th valve usable whilst leaving other combinations (13, 123) unusable...
    Perhaps this is why Bari players I know seem to prefer 3v compensators to 4v Bari's?
     
  15. MoominDave

    MoominDave Well-Known Member

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    Minor digression, one that's had its own threads in the past...

    Other reasons to prefer 3V compensating baris to 4V:
    - Weight
    - Lack of need in written parts
    - Adding the valve sometimes gets bundled up with a bore size increase, making the sound too euphy

    I'll leave further comment to bari specialists as last time I tried to assert things on the subject someone more knowledgeable turned up and pointed out something that I'd got wrong...
     
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  16. MoominDave

    MoominDave Well-Known Member

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    If you recall that spreadsheet I made a while back that calculates fingering charts for any instrument of any tuning with up to 6 valves, this information is in there, on a subsheet, though not displayed very helpfully. I'm just fiddling with it to try to make it be more helpful.
     
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  17. 2nd tenor

    2nd tenor Well-Known Member

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    I do seem to recall something but quite where that information is now escapes me. Whatever, what I’m hoping for is to somehow add that reference data to this thread.
     
  18. GJG

    GJG Well-Known Member

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    That seems to be the main objection to 4v baris, based on the conversations I've had with bari players. makes sense to me; very important not to lose the true, distinctive baritone sound from the blend.
     
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  19. MoominDave

    MoominDave Well-Known Member

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    Right, fixed it up now. I can post screenshots to the thread of tunings of all available fingerings for a note. Valve tuning options available are

    System number 1a System name 3-valve non-compensating, with 3rd valve tuned to A
    System number 1b System name 3-valve non-compensating, with 3rd valve tuned to Ab on 2+3
    System number 1c System name 3-valve non-compensating, with 3rd valve tuned to make Ab 8 cents flat
    System number 1d System name 3-valve non-compensating, with 3rd valve tuned to G on 1+3
    System number 1e System name 3-valve non-compensating, with 3rd valve tuned to F# on 1+2+3
    System number 1f System name 3-valve non-compensating, with 3rd valve tuned to Ab on its own
    System number 1g System name 3-valve non-compensating, with 3rd valve tuned to F on 1+2+3
    System number 2a System name 4-valve non-compensating, with 3rd valve tuned to A
    System number 2b System name 4-valve non-compensating, with 3rd valve tuned to Ab on 2+3
    System number 2c System name 4-valve non-compensating, with 3rd valve tuned to make Ab 8 cents flat
    System number 2d System name 4-valve non-compensating, with 3rd valve tuned to G on 1+3
    System number 2e System name 4-valve non-compensating, with 3rd valve tuned to F# on 1+2+3
    System number 3 System name 4-valve non-compensating, with 4th valve tuned to Ab (e.g. Czech valve bass trombone)
    System number 4a System name 3-valve compensating
    System number 4b System name 3-valve compensating with only 1st valve compensated (on 3rd)
    System number 5 System name 4-valve compensating
    System number 6 System name Hawkes "Dictor" model: 4-valve with only 4th valve compensated (on 3rd), and 4th tuned to F#
    System number 7 System name 5-valve euphonium model, early 20th century; 5th valve duplicate of 2nd
    System number 8a System name Double French Horn
    System number 8b System name Double French Horn with ascending 5th side
    System number 9a System name Double French Horn with French ascending valve
    System number 9b System name Single French Horn with French ascending valve
    System number 10a System name 5-valve tuba, with 5th valve tuned to perfect 5th on 4+5
    System number 10b System name 5-valve tuba, with 5th valve tuned to short major 3rd (tuned to F# on 1+2+5)
    System number 10c System name 5-valve tuba, with 5th valve tuned to tritone
    System number 11 System name 6-valve tuba, with 5th valve tuned to F on 4+5 and 6th valve tuned to E on 4+6
    System number 12 System name 6-valve French tuba in high C
    System number 13 System name 2-valve bugle
    System number 14 System name Unvalved
    System number n System name Custom

    Which one would you like me to post? There are several (mostly variants of system 1) of relevance to this thread.
     
  20. MoominDave

    MoominDave Well-Known Member

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    System 1b: 3 valve non-compensating with 3rd valve tuned to make Ab in tune on 2+3

    First, the usual fingering chart that the spreadsheet generates
    , which balances perfection of tuning against being lower in the harmonic series, so the instrument responds better. Note that the octave label refers to the highest note in the octave listed. So "middle C" is 11 semitones above "middle C#" even though one might perhaps more usually refer to the C# as "bottom C#". Tunings are given in cents, + is sharp, - is flat. Position in the lower chart corresponds to fingering in the upper chart.

    upload_2019-3-2_19-14-16.png

    Second, the list of alternative fingerings.
    Fingering combos are listed down the left, and notes through the range from left to right - I've picked out the used register. Tunings are listed as in the chart above: + sharp, - flat, in cents - so 100 = 1 semitone. e.g. C 50 cents sharp is the same thing as C# 50 cents flat - we're assuming equal temperament here. Where there are multiple entries under a note, that indicates alternative fingerings. I've applied a cut-off of +-60 cents from ideal - so some combos that are about halfway between two semitones when unadjusted are shown under both adjacent notes (e.g. 'C#' on 1+2+3, so sharp it's almost nearer D).

    upload_2019-3-2_19-17-46.png

    @2nd tenor, one can see the 1+2 option for high G that you mentioned, listed at ~20 cents flat (~1/5 semitone). With that specification, it might be the right solution in some circumstances (middle of a fast run, say, though it's hard to imagine the run that fingering high G ("top G" in this chart) on 1+2 would make easier), but is an unlikely candidate. It's a lot better than playing it on the near equivalent 3, but then in this scheme, 3's been pulled out to get an in-tune Ab, so it's longer than some have it. Far and away the best option tuning-wise (and response-wise too) for "top G" is open - if the instrument/player combo behaves in ideal acoustic fashion - but then of course they don't always...

    Btw, the weird speckling in the colour on C#s is due to my PC graphics card being on the way out - shows up in the screenshotting :)

    That should cover anyone with a cornet, more or less, which is where the thread started. If anyone wants to request any others from the list above (or not on the list), I can easily supply them similarly.
     
    Last edited: Mar 2, 2019
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