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tony

Timbre

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Now, time to go and renew my membership of "The Flat Earth Society", where's my quill pen ?  :P

 

 

Ooops!

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Thank you Howard. A splendid answer, paricuarly this last point.

 

putting a weight on the end of the reed makes the fundamental louder in proportion to the upper harmonics and results in a less "reedy" tone.

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I'm afraid we're talking "old technology" here, not "Rank Xerox".   :(
You may be surprised at how old Xerography is.

Not really, but I'm talking about the technology of 100 years earlier, whilst I expect 914 technology would be considered "antiquated" today.

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I'm afraid we're talking "old technology" here, not "Rank Xerox".  :(

A digression, I know, but: Being from America, where Xerox originated, I've never understood what was so rank about the British version that they had to warn people by putting it in the name of the company. :o :unsure: :D

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- putting a weight on the end of the reed makes the fundamental louder in proportion to the upper harmonics and results in a less "reedy" tone.

Personally, I would describe it by simply saying that it deadens the tone, but it all boils down to the same thing as your more technical version. Mind you, it also means that the reed needs an extra "kick" to get it started.

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- putting a weight on the end of the reed makes the fundamental louder in proportion to the upper harmonics and results in a less "reedy" tone.

Mind you, it also means that the reed needs an extra "kick" to get it started.

And there are, "of course" variations in the way the weight can be applied.

 

It can be a tall "chunk" restricted to a region very near the tip, or it can be a more extended region with a lower profile. I suspect the latter would require slightly more total weight, and it would also reduce the flexing of the reed over that length. But I don't know how much of the flexing normally occurs near the tip on a long reed, nor how the different distributions of increased weight and stiffness would affect the timbre.

 

Also, I think it would be important to set back or bevel the added mass sharply away from the edges of the reed; otherwise the tip will have to sink much too far before spilling the air and starting its return journey. I.e., I would expect that an added mass squared to the edges of the reed would adversely affect response.

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Jim: "Also, I think it would be important to set back or bevel the added mass sharply away from the edges of the reed; otherwise the tip will have to sink much too far before spilling the air and starting its return journey. I.e., I would expect that an added mass squared to the edges of the reed would adversely affect response."

 

Comment: You're probably right, but I think it would all depend on the amount on weight added. Not very much is neded to lower a reed by a full tone.

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Would someone please define for me exactly what timbre means? Is it the same as tone or does it mean something else? Thankyou

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Would someone please define for me exactly what timbre means?  Is it the same as tone or does it mean something else?  Thankyou

It is that property of a sound that makes it recognizably different from other sounds (excluding frequency, or pitch). It is determined both by the shape of the sound wave (ie., the overtone series) and the peculiarities of human hearing.

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So timbre is not the frequency of pitch or tone but is the shape of the soundwaves?

My understanding is that "timbre" is what many of us refer to as "tone quality", that quality -- or those qualities -- of the sound that's neither pitch nor loudness, but everything that makes instruments playing the same note sound different from each other. While it's a property of the sound waves that could be described as "shape" or "harmonic spectrum", or by various other technical terms, looking at the sound wave or its spectrum on a computer screen isn't going to tell you what it sounds like. Only listening can do that.

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So timbre is not the frequency of pitch or tone but is the shape of the soundwaves?

Jim,

 

Here are a couple of technical definitions, from http://hyperphysics.phy-astr.gsu.edu/hbase/sound/timbre.html :

 

Sound "quality" or "timbre" describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Timbre is then a general term for the distinguishable characteristics of a tone. Timbre is mainly determined by the harmonic content of a sound and the dynamic characteristics of the sound such as vibrato and the attack-decay envelope of the sound.

 

The shape of the soundwaves is determined by the "harmonic content", the number and relative intensity of the upper harmonics present in the sound.

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Thanks. Its what makes my concertina sound different than your concertina. With that in mind I'll trudge through the discussion again.

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Its what makes my concertina sound different than your concertina.

More in keeping with the more common use of the word, it's what makes your Concertina sound different from my Cello and Jim's French Horn. Subtle differences between the way different concertinas sound have only much more recently been referred to as "timbre."

 

Let me try to clarify with some examples.

 

A Trumpet playing a D and the same Trumpet playing an Eb have the same timbre, but different pitches.

 

A Violin and an Oboe playing the same note have different timbres.

 

Two hypothetical instruments that sound confusingly similar bit produce their sounds in different ways (I can't think of an example right now) likely have very different wave forms but the same timbre.

 

Two Concertinas, if and only if they can be distinguished on the basis of how they sound, have different timbres.

 

This will, of course, vary with the listener. To someone who doesn't know Concertinas well ("all Concertinas sound alike"), they will have the same timbre. To someone who services Concertinas professionally, each reed of a single instrument may have a different timbre, and even that may vary with the pressure in the bellows and atmospheric conditions.

 

Minor editing changes.

Edited by David Barnert

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Anyone who states that something does not exist, such as a formulae, belongs to the Flat World Society. If they are saying they know of no such formulae then that's fine but they, at least, could leave the Forum open for someone who may know.

Tony,

 

If there was some sort of magical "formula" (let alone formulae), then all free reeds would be made in the same way and sound just the same. Fortunately, different makers have their own ideas on how to make/voice reeds, giving them a "personality" of their own. But I'm afraid it's more like alchemy than physics.

 

As Bob Tedrow has stated :

These adjustments must be done by hand and ear.

 

There exists no formula to balance these properties.

I'm sorry if that offends your rationale.

 

But frankly, I find your implication offensive, that some of the people who have tried to discuss the subject for your benefit are ignorant, and need to join the Flat Earth Society. :angry:

 

(Edited to add quote from Bob Tedrow.)

Edited by Stephen Chambers

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For what it’s worth I carried out a small experiment and these are my findings.

 

On removing both ends of my 46 key Lachenel Maccan I determined that the reed shoes for the G above middle C on the treble and bass sides of the instrument were the same size. I swapped them over and could detect no difference in how well they fitted. I reassembled the concertina and measured the pitch on my Korg CA-30 meter. Having measured the pitch prior to dismantling I found no measurable change in pitch. The timbre did not transfer with the reeds.

 

I removed the ends again and returned the reeds to their original locations.

 

I then measured the dimensions of the chambers. My measuring tools were a thin piece of card, a sharp pencil and a standard ruler. These are my findings:

 

Treble side (in millimeters): Length (two sides): 38 and 34. Width (two sides): 17 and 7. Depth (two sides): 10 and 10. From this I calculate the volume to be approximately 6120 cubic millimeters.

 

Bass Side (in millimeters): Length (two sides): 37 and 34. Width (two sides): 15 and 6. Depth (two sides): 9 and 8. From this I calculate the volume to be approximately 4526 cubic millimeters.

 

The distance the pads moved when each key was pressed was near enough the same. 10 mm.

 

This means that the volume of the chamber on the treble side is something like 35% larger than the volume of the chamber on the bass side.

 

I am not a sound engineer and am therefore not prepared to declare any firm conclusions, however, I do have my suspicions, which are as follows:

 

1. Changing the profile of a reed tongue in order to alter its timbre is probably a fruitless exercise.

 

2. The chamber volume, rather than its shape, has the greatest affect on timbre and, for me, changing this is not an option on a vintage instrument.

 

My findings are probably coumpounded if you add the following suggestion:

 

Hi Stephen,

 

Sorry I wasn't clear.  I meant (and thought I wrote) that some high notes on the LH side have pads that open away from the player (hence brighter in timbre), but the low notes on the RH side (which ARE those same pitches, making up the "overlap") may be more likely to have pads that open under the right hand (hence duller in timbre).

 

Anyway as you say there are many causes for such differences!

 

Thanks,

 

Paul

Edited by tony

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