Audacity Trumpet Spectra

Discussion in 'Trumpet Discussion' started by Sethoflagos, Apr 18, 2015.

  1. Sethoflagos

    Sethoflagos Utimate User

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    Just to reinforce the caveat emptor warnings, this is the spectrum I get when I 'push' the Yamaha (a pretty good forte+):

    [​IMG]

    I still see the energy spread fairly evenly across the first 5 harmonics, which seems to be a fingerprint of how the Yamaha plays me. But the cautions are correct. It's very easy to jump to unwarranted conclusions.


    6) Be absolutely clear in your mind as to what exactly you are trying to measure.


    I think there's pretty solid agreement here that there is a big difference between measurements taken of the equipment in isolation, and a more holistic approach that looks at the performance of instrument and performer combined. While the first is sort of interesting at an academic level, I'm a fair bit more interested in what's going on when it's me playing them, in the way that I play them (or that they play me). This is of necessity highly subjective, and most definitely will not give a "trumpet X is better than trumpet Y" result. But seeing how different people can get different results on the same basic equipment set up is interesting in itself, isn't it? And maybe of more practical significance to us as performers rather than amateur physicists ;-)
     
  2. tjcombo

    tjcombo Mezzo Forte User

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    Seth, I see that the peak SPL shows as -12dB on this graph (similar to the others), so I guess that you're adjusting either the input level on your PC or backing away from the mike. Interesting that the spectrum is similar to your Wild Thing once you light up the Yamaha - not unexpected I guess.

    Rowuk, I've always taken these tools in Audacity as an interesting and useful plaything rather than a serious lab-grade tool. I originally posted some shots in response to a claim on TM that a particular horn had a "pure tone" to demonstrate that the trumpet sound is comprised of a wide mix of harmonics. BTW, thanks for the link to Hansen's document. It looks well worth digesting (90 pages in this age of 140 character tweets!).

    To do some testing with a signal source I was thinking about sweeping the frequency and measuring levels at both input and output. It's on the list of projects, but will have to wait until I finish moving house.

    In terms of real uses for the information, it partly satisfies my inner nerd but also feeds into what goes on in my head whilst playing - certainly not a direct correspondence as in "I want dark, don't let my lips flap together" :-)
     
  3. Sethoflagos

    Sethoflagos Utimate User

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    Decibels is one of my least favourite units. It's a logarithm of a ratio of measured value to some fixed reference. So you always have to ask yourself a) what are you actually measuring, and b) what is the fixed reference. People that use dB somehow seem to expect you just to know, and it isn't often obvious.

    My understanding is that Audacity's Spectrum Analysis tool is measuring (something roughly proportional to) acoustic energy within a particular frequency band, and that the fixed reference is the total acoustic energy over all frequency bands. So the 'dB' figure in the vertical axis is 10 times the logarithm (base 10) of the fraction of the total acoustic energy that's contained within a particular band.

    So the total acoustic energy (100%) = 10 x log (100/100) = 0 dB
    10% of total acoustic energy = 10 x log (10/100) = -10 dB
    1% of total acoustic energy = 10 x log (1/100) = -20 dB

    ...and so on. So the peaks don't relate to absolute power or volume, but some pro rata to the total.


    'Similar' certainly. I'm currently cogitating on the hypothesis that the long 'tail' might actually be distortion and that I may simply have to push the Yamaha harder before the sound starts 'breaking up'. Now there's a thought!

    There are some differences in the relative strengths of the core harmonics which seem to repeat fairly consistently, but these differences pale into insignificance when I switch mouthpieces.

    My pet screamer for the Yamaha is a Denis Wick 4X Heavytop - feels like it could cut through steel plate. This is the trace I get with that one full belt (or at least exceeding Mrs Seth's tolerance threshold):

    [​IMG]

    ...really heavily weighted toward the 2nd harmonic.

    I'd be a little more generous. At the heart of the beast, Fast Fourier Transforms are a pretty standard and proven mathematical technique so I'd guess that Audacity probably does a pretty good job with the input that's fed to it. My doubts would focus on the quality of the inboard microphone array in my laptop hence I'm currently in the process of obtaining a decent instrument mike and mixer board.
     
  4. Ed Lee

    Ed Lee Utimate User

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    Whereas sound is a natural phenonomen, why aren't you calculating in natural logarithms (Euler) in lieu of decimal base? Oh well, calculus is an advanced mathematics beyond the majority of the populace. Without such, with precision we can not determine our geographic position in correlation to present in use mapping datums. Oh my ... just don't call for rescue by the Coast Guard / Navy if you are lost on land and even our U.S. Air Force wouldn't know where you are from your call. Yep, one U.S. military branch doesn't speak geographies to another ... remember Grenada. OK, I diverge, but as to music, it is the same consequence when we are lost ... we don't speak/write the "language" of most others. This graphing does nothing to improve the music of a student or my own performance and is not taught in any collegiate level music course I've knowledge of. Lots of the gimmicks on the current market have no practical application or value.
     
  5. trickg

    trickg Utimate User

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    I'm with Ed on this one. This thread, to me, is kind of like picking gnat turds out of pepper - while one "can" take the time to do the analysis, I'm not sure what it really proves or how useful it might be from a musical perspective. We use our ears and musical judgment to use the proper gear with the proper sound for the kinds of recordings or performances we do, and we are constantly making minor adjustments in our sound, all done instinctively, based on what we hear, with our every time we play in an ensemble.
     
  6. Sethoflagos

    Sethoflagos Utimate User

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    .....then go away and do whatever makes you happy, and spare those of us who like this stuff your negativity.

    Simples. :-)
     
  7. trickg

    trickg Utimate User

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    The last time I checked, this forum was created as a means to discuss whatever came along and to embrace, not discourage, alternate ideas and opinions. I know - I was one of the founding members here.

    Regarding that, nothing either Ed or myself said was negative. It was simply pointing out the obvious - when it comes to making real music, none of this analysis really means much or even matters to the end result. I could pick up the very same horns using the very same mouthpieces, and my sound spectrum is going to look completely different than you because we are different players with our own distinct sound qualities. It might be interesting from an academic perspective, but it's not going to help anyone in their efforts to make music, and it may even hinder - over-analysis is usually considered a bad thing where making music is concerned.
     
  8. Sethoflagos

    Sethoflagos Utimate User

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    Patrick,

    If you wished to be genuinely constructive on this thread, you would not have begun your diatribe with a toilet metaphor. So don't give me the free speech nonsense. Most of us can manage simply to abstain from the threads we're not interested in.

    I know that you've been wanting to take a pop at me for a while.

    It's okay. It's a safe environment for you. It isn't like we're face to face or anything.

    So.

    Have you done?
     
  9. Ed Lee

    Ed Lee Utimate User

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    Are such as you a minority or majority on TM? Poll? Oh durn, that would be more of a waste without developmental musical educational content.
     
  10. trickg

    trickg Utimate User

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    I was being constructive in the thread - I tend to approach things from a no-nonsense, common-sense point of view when it comes to my efforts with the horn. Again, it may be interesting from an academic perspective, but past that?

    The problem doesn't come when it's guys like me who read these threads because I know enough to know what to pay attention to, and what could/should be ignored. But what about an aspiring HS kid who comes across this thread? All of a sudden you've got a kid who may think they need to go out and get some other horn because of your spectra analysis, or they get all wrapped up in it when what they need to be focused on it's what it really SOUNDS like when they play, and what they can do to improve their performance in an ensemble. Those little instinctual things that start to happen when your ears become better trained, so that you automatically make the adjustments based on what you hear, rather than worrying about things like if there are enough highs or mids represented in their sound with the particular horn/mouthpiece they are using, when ultimately, it really doesn't matter.

    And Seth, check your ego at the door - do you really think you matter so much that I've been waiting around for you to post something so I could "take a poke" at you? I didn't even take note of who started the thread before I commented - I didn't even realize it was you until you got all bent about it. Ok, so you didn't like the "gnat turds" metaphor - apologies for that, even though I think it applies - and I'll stand by everything else I've posted because ultimately none of it matters - not recorded, (you can EQ and bump/cut any freq's that need to be bumbed or cut) not live in an acoustic situation, and not in a live mic'ed/amplified situation when freq's can be bumped or cut at the board.

    If we were face to face, I'd say the same things.
     

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