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Brighter G string


H.R.Fisher

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6 minutes ago, fscotte said:

More high frequency or less low frequency will brighten your G string. 

I very much agree.  It's just a question of how to achieve it.

My last experimental flat top viola was made with five internal longitudinal braces but no cross braces and it sounded "tuby", "dark", "dull" and "damn it".

I then glued cross braces on the outside in various sizes, numbers and positions to increase the plates stiffness in that direction and the sound color eventually became much brighter and quite pleasant for me.

As an example the open string G note was played and recorded with Audacity before and after the last cross braces were added. The amplitudes of each of the first G note's harmonics were found which show the differences between the two conditions.  The amplitude of low frequency harmonics were reduced and the higher ones were increased as you mentioned.

One measure of "brightness" is the centroid or center of balance of the harmonics which can be presented in either as the harmonic's number centroid, or the harmonic's frequency centroid.

For example my viola had an open G note centroid of 8.0n or 1564Hz before the cross braces were added and 9.1n or 1793Hz after all the cross braces were glued on which show the increase in brightness.

Attached is some background on brightness.

2024_02_22_1441.JPG

Harmonic number .png

No. 45 G note.png

Tone color or timbre quality.pdf

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So in response to matestic's observation i was trying to find a working definitoin of 'dullness' in relation to timbre.  I didn't find much, but this lexicon of signal descriptors may be useful: http://recherche.ircam.fr/equipes/analyse-synthese/peeters/ARTICLES/Peeters_2003_cuidadoaudiofeatures.pdf

Now, I agree part of this discussion can easily become effectively useless for answering the OP's question in a meaningful way, so I'm jumping to the camp of those (Mr. Kasprzyk for example per above) who just want to increase the 'high' frequency content of the tone, and for convenience measure it by the spectral centroid defined as the amplitude-weighted mean of the violin's power spectrum.  The 'how it sounds' test is an alternative, but difficult to quantize although - again as stated and implied multiple times above - it is the ultimate alternative.

I think, from the experimental work reported here and elsewhere - and here I'm referring to traditional violins - the best way is to ensure that materials properties are within the range of empirically good violins, that arching, thickness, and other parameters are similarly consistent (Mr. Noon has expounded at length on much of this), that varnish and setup are according to best practice - strings, sound post, bridge are selected/carved/adjusted to mitigate any deficiencies and bring out the best from the instrument.  After that, talk with your violin instructor or experiment with your technique.  Is all of this reasonable?  How all of this is done is a matter for people with more experience and expertise than I have, but I do like well-defined problems where primary alternatives have been discussed.

 

 

 

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2 hours ago, matesic said:

Rereading the OP's first two posts, I don't see the word "dark" but "dull or muted". The analogy with light breaks down because in sound "bright" has two antitheses.

Doesn't "light" also have at least two antitheses? One would be the absence of electromagnetic energy, and another could have lots of electromagnetic energy, but be lacking in those which are perceived by the human sensory system?

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On 2/21/2024 at 5:07 PM, Dr. Mark said:

The closest we can get to objective is a scientific definition, i.e. a term is accepted by practitioners to correspond with a measurable quantity that has a specified value or falls in a specified range.  As indicated by Mr. Burgess and matestic above even that is no guarantee that our experience is the same, only that we all agree on the definition of the term.  Maybe there are violins that everyone would agree are 'dark'.  Some measurable quantity that differentiates between those and any other violin would be nice - Mr. Noon, Mr. Buen, or Mr. Kasprzyk may know if that exists...

 

I am curious if you can say more about this as I have some issue with one of my cellos. Also I would like to ask what qualifications or competency have you in this musical/making instruments field. Are you a PhD in music ? Some other field ? Medical Dr. ? I knew very talented medical doctors violin players.

Thank you.

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2 hours ago, VicM said:

I am curious if you can say more about this as I have some issue with one of my cellos. Also I would like to ask what qualifications or competency have you in this musical/making instruments field. Are you a PhD in music ?

First - My doctorate is in Physics, and much of my early work was in transient signature analysis.  I have a bio posted here with about all I should say about my career since then.

I don't claim competence in any musical field which is why I typically defer to others.  I played violin for some time, but you know how it is - not everyone is suited for it.  What contributions I try to make are when the topic touches on something I have relevant experience with, knowledge of, or questions about.  But for matters requiring some form of musical expertise, such as might be the case with your cello, I would strongly suggest that you start a thread and explain it for the experts on this site.   They'll certainly help if they're able to, and it may be in the form of advice - which you should take.  All my subjective opinion lol.

 

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10 hours ago, Dr. Mark said:

....

I'm jumping to the camp of those (Mr. Kasprzyk for example per above) who just want to increase the 'high' frequency content of the tone, and for convenience measure it by the spectral centroid defined as the amplitude-weighted mean of the violin's power spectrum. 

 

Hi Dr Mark, perhaps I'm misreading what you meant to say but the method of finding the centroid(s) in the paper from Marty is per each note rather than the instrument as whole.  If you were to plot the impulse response at the bridge (eg to a microphone etc)  it would be a different curve to that of all the centroids of individual notes plotted together because those also depend on how much of each harmonic is generated by the bowing or plucking of each string.

There a string factor, a bridge factor and a bowing factor all convolved with the response curve of the body itself. 

Add a bit of psychoacoustics to season and it gets messy, fast. 

 

Btw due to various acoustic insults the frequency responses of my two ears  differ and neither of them work as high as they used to. Should I be listening with my dark ear or my bright ear?

 

 

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4 minutes ago, LCF said:

the method of finding the centroid(s) in the paper from Marty is per each note rather than the instrument as whole.

I should have been clearer - I was only referring to the metric for determining whether the 'high frequency content of the spectrum' has increased, and concurring with those who accept that an increase in the metric corresponds to an increase in 'brightness' - see for example the brief paragraph entitled 'Brightness' in the 'Timbre'  Wiki page.  Circumstances may require a reconsideration - e.g. if some revenant of a customer (to coin a phrase) isn't satisfied.  Ways and means of obtaining an appropriate spectrum are a matter of the particular conditions and acuity of the individual(s) running the test I would imagine.

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1 hour ago, Dr. Mark said:

I should have been clearer - I was only referring to the metric for determining whether the 'high frequency content of the spectrum' has increased, and concurring with those who accept that an increase in the metric corresponds to an increase in 'brightness' - see for example the brief paragraph entitled 'Brightness' in the 'Timbre'  Wiki page.  Circumstances may require a reconsideration - e.g. if some revenant of a customer (to coin a phrase) isn't satisfied.  Ways and means of obtaining an appropriate spectrum are a matter of the particular conditions and acuity of the individual(s) running the test I would imagine.

Yes, there's always going to be  questions as to what your centroid determining algorithm is, and I'll throw two into the mix. First, that spectral centroid is pitch agnostic but if you've ever sped things up and slowed them down, perceived tone is not constant. Second not all harmonic mixtures sound as bright as others although they may have the same centroid. The classic example is clarinet vs saxophone where clarinet has mostly odd harmonic content 1 3,5,...,2n+1  but sax, and oboe also have even numbers in the mix making a complete series. There's little doubt that sax sounds 'brighter' than clarinet. 

 

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It’s a perfect example

A sax is bright compared to a clarinet but not compared to a violin.

So unless you wish to determine some universally agreed centre point for human auditory impulses, we are always making comparative and necessarily subjective judgments.

Call it pretentious bullshit if you like … I don’t mind.

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41 minutes ago, matesic said:

Sorry, there's considerable doubt here! it's in my head, where all the inexplicable, uncommunicable, subjective stuff goes on.

Accepted!  But substitute oboe for sax if it lessens the pain.   :)

 

Certainly more 'trebley', less smooth.  

My subjective  words, sorry. 

No-one has mentioned synesthesia yet.  

 

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2 minutes ago, David Burgess said:

OK. For me, the sound of a clarinet brings up images of flying pigs and dancing elephants. Is it kangaroos and koalas for you? ;)

I was traumatised by Fantasia as a small child so now that you've mentioned dancing elephants I'll need to hide under the couch for a while. 

 

 

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I have a history in microphonics.  Yeah that's a made-up term, I used to collect and use and record with a lot of various vintage microphones and more modern ones as well.

The easiest way to brighten any instrument, was to use a microphone that had a better high frequency response.  Or use a microphone that had a diminished low frequency response.

As Marty pointed out, I think it's pretty simple. Increase the stiffness, and you will increase the brightness.

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27 minutes ago, David Burgess said:

I need to put longer legs on my couch so I can hide from clarinets.

You can make two couch leg extenders from every metal flute you cut in half with a hacksaw. Or with a sawsall. 

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18 minutes ago, fscotte said:

I have a history in microphonics.  Yeah that's a made-up term, I used to collect and use and record with a lot of various vintage microphones and more modern ones as well.

The easiest way to brighten any instrument, was to use a microphone that had a better high frequency response.  Or use a microphone that had a diminished low frequency response.

As Marty pointed out, I think it's pretty simple. Increase the stiffness, and you will increase the brightness.

Or the harshness.

Or the roughness.

 

Marty's pics of his experiments are always so inspiring though. The specific places he put all those extra braces are very interesting. 

 

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3 minutes ago, matesic said:

I'd call the sax sound "mellow". Define that according to the harmonic spectrum if you can.

Surely all instruments produce some inharmonic noises too which could be responsible for their timbral differences

Recent thread here about the startup transients from bowing which can be very gritty. Chaotic.  Some people like it and what it represents for articulation. Sometimes, on some fiddles it makes my teeth grate. 

 

Sax and clarinet are both single reeds which are usually milder sounding than double reeds. There used to be a tiny single reed beak adaptor available for oboes which made them easier to play and more 'smooth' sounding. 

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8 minutes ago, LCF said:

Or the harshness.

Or the roughness.

 

Marty's pics of his experiments are always so inspiring though. The specific places he put all those extra braces are very interesting. 

 

Btw if you record a couple of seconds of steady tone on most reed instruments then copy paste it a few times and filter each copy for specific  harmonics such that you get #1 then #2 etc, by the time you get to about #8 or #10 whatever is left over is a weird collection of wheezes and rattles. 

Most people aren't capable of listening to a steady tone and perceiving specific harmonics but using the filtering  technology you can train yourself to do that.  Or hanging around with pipe organ builders you soon get to identify a quint or a tierce.

In Marty's linked article it's interesting that they identify the fifth harmonic of G as one determinant. Fifth harmonics, #5 and #10 etc not IV!, are really very unpleasant to my ears. Pure major thirds. #7 can be a bit manky too. 

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13 hours ago, LCF said:

not all harmonic mixtures sound as bright as others although they may have the same centroid.

...which suggests that we might improve the metric by windowing in the frequency domain with the human auditory response.  Interesting idea.  Nothing is perfect - except maybe Mr. Bayon's antiquing and the L-N 120 low-angle block plane (by many accounts).

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7 hours ago, Dr. Mark said:

...which suggests that we might improve the metric by windowing in the frequency domain with the human auditory response.  Interesting idea.  Nothing is perfect - except maybe Mr. Bayon's antiquing and the L-N 120 low-angle block plane (by many accounts).

Think about the difference between a triangle wave and a square wave as an ideal case. Square wave = only odd harmonics. Triangle = complete harmonic series. You can then change the coefficients in the two sets of harmonics to favour the highs or the lows or whatever mix you like to move the spectral centroid all over the place. Then as you suggest, convolve that with other time varying functions. 

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8 hours ago, Marty Kasprzyk said:

When I finally understood the physics of making harsh sounding instruments I got quite good at it.

Attached is a summary  paper on what causes harshness and roughness.

Part 1 section 3.2 on harshness.pdf 4.66 MB · 5 downloads

Yes, triangles and sawtooths, first cousin waveforms. I love the way it all boils down to integers, geometry and onomatapoiea.

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