Spectum of a concertina

[david fabre]

In a recent thread initially devoted to reed plates, there was an interesting discussion about the differences in

sound between concertinas and accordeons, and the reasons for there differences according to the design of

both types of instruments. Some contributors argued that these instruments have very different spectra, that of

the accordeon being richer in harmonics.

 

I don't have a spectrum analyser in hand, but would be interested in seeing exactly how

the spectra differ. Maybe someone has such things in hand and could post them ; or indicate where

it can be found.

 

According to my own perception, I would describe the sound of a concertina (at least my Wheatstone)

as "muted" (I mean somehow like a muted trumpet) and "sharp", and I would expect this to be related to a

relatively low level of lower harmonics, but with a peak in the higher regions of the spectrum.

 

On the other hand I perceive the sound of accordeon as "rounder" and expect this to be related

to a more regular distribution of harmonics, with more energy in the lower ones and less in the higher ones.

 

Is that correct ?

[Johann]

@david fabre

 

 

"I don't have a spectrum analyser in hand, but would be interested in seeing exactly how

the spectra differ. Maybe someone has such things in hand and could post them ; or indicate where

it can be found."

 

You could install Software on your PC that is well usable for analysing, but don't expect the Graphical display as very reviling.

Or ear is much more sensitive.

 

"According to my own perception, I would describe the sound of a concertina (at least my Wheatstone)

as "muted" (I mean somehow like a muted trumpet) and "sharp", and I would expect this to be related to a

relatively low level of lower harmonics, but with a peak in the higher regions of the spectrum."

 

Muted sound often is the case if some sound absorbing stuff is present or if the covers are very air tight with minimal openings.

 

"On the other hand I perceive the sound of accordion as "rounder" and expect this to be related

to a more regular distribution of harmonics, with more energy in the lower ones and less in the higher ones."

 

The difference in sound is related to many Factors not only the reed!

Still the reed is one of the main Factor.

A modern accordion reed usual produces much more Harmonics in the higher regions,

mainly because the distance between the moving Reed Tongue and the Frame slot is less as on older reeds.

 

Johann

[david fabre]

"According to my own perception, I would describe the sound of a concertina (at least my Wheatstone)

as "muted" (I mean somehow like a muted trumpet) and "sharp", and I would expect this to be related to a

relatively low level of lower harmonics, but with a peak in the higher regions of the spectrum."

 

Muted sound often is the case if some sound absorbing stuff is present or if the covers are very air tight with minimal openings.

 

Describing tones with words is very difficult, and very subjective.

The word "muted" is certainly too strong. Moreover, this word comes to me only

when comparing concertina with accordeon. I beleive that the quality I call "muted"

is the same that would be called "nasal" by some if too accentuated.

 

To me the difference of tone between concertina and accordeon is very

similar to that between clarinet and saxophone, and I beleive the spectra of

these instruments differ in a similar way, the clarinet having less lower partials

(especially the even ones which are nearly missing).

[Johann]

... s the same that would be called "nasal" by some if too accentuated.

 

If if it is real nasal effect this would mean that "formation" of the sound occurs as it is the case when one closes the nose when talking.

Formation of the sound is different in concertinas as in Accordions but usual it is considered that the resulting effect is not very strong.

Formation (resonance) has nearly nothing to do with the reed itself.

[david_boveri]

in the past i have used this software: http://www.virtins.com/ (multi instrument 3.1). even with a cheap mic you could get some good readings. it can be a little heady if you dont know how to use it... i dont think i would have not been able to figure it out of i hadnt been using it in class.

[Johann]

in the past i have used this software: http://www.virtins.com/ (multi instrument 3.1). even with a cheap mic you could get some good readings. it can be a little heady if you dont know how to use it... i dont think i would have not been able to figure it out of i hadnt been using it in class.

 

Thanks, had a look at this program, nothing special about it. There are better spectrum analysing tolls available. Waterfall Display is preferable to see a bit more but one has to know for what one is looking for. A trained ear hears much more as one can see on this graphical reproduction of the sound.

[david_boveri]

in the past i have used this software: http://www.virtins.com/ (multi instrument 3.1). even with a cheap mic you could get some good readings. it can be a little heady if you dont know how to use it... i dont think i would have not been able to figure it out of i hadnt been using it in class.

 

Thanks, had a look at this program, nothing special about it. There are better spectrum analysing tolls available. Waterfall Display is preferable to see a bit more but one has to know for what one is looking for. A trained ear hears much more as one can see on this graphical reproduction of the sound.

 

yeah, i know it is not very advanced as far as these things go, but it's cheap and accessible.

 

i wonder what you mean by that the ear is more sensitive--one cannot systematically analyze spectra with the ear, and this is what the original poster is asking about. i think that one can begin to see meaningful differences between the spectral analysis of the concertina and the accordion on even cheap software like this. to do anything more rigorous you would need much more advanced tools, for sure.

[Johann]

i wonder what you mean by that the ear is more sensitive--one cannot systematically analyze spectra with the ear, and this is what the original poster is asking about. i think that one can begin to see meaningful differences between the spectral analysis of the concertina and the accordion on even cheap software like this.

Yes you are right, one sees differences but it is very hard to point the heard to the right spot in the graphical few. And in most cases the few will be wrongly interpreted.

[Henrik Müller]

i wonder what you mean by that the ear is more sensitive--one cannot systematically analyze spectra with the ear, and this is what the original poster is asking about. i think that one can begin to see meaningful differences between the spectral analysis of the concertina and the accordion on even cheap software like this.

Yes you are right, one sees differences but it is very hard to point the heard to the right spot in the graphical few. And in most cases the few will be wrongly interpreted.

It is easy to be seduced by the existence of spectrum analysis software. I had a closer look into audio analysis during my time with the Danish Acoustical Institute (part of Delta today). Once you had the analyzer (at that time a dedicated Brüel & Kjær mammoth unit), you needed two things more:

 

1 - a microphone with a response as flat as the floor - another B & K device, cost a small car

2 - an anechoic chamber - nothing you'll find at the local hardware store... it is dead, stone-dead, acoustically - if you fire a blank 9 mm shot inside it, it sounds like a teenager popping her gum.

 

Why the chamber is needed: when sound is emitted from a source and picked up by a microphone, the microphone will receive a mixture of direct sound and reflections from the surroundings. The reflections from the near surroundings will work against or with the direct sound, depending on the phase. (Think of phase as a delay so short that it isn't an echo - it is shorter than the period of one cycle of a specific frequency. Related posts: the doppler effect, but we won't go there ).

 

With the high harmonic content of free reed sounds, the whole set-up will be extremely sensitive to reflections.

 

I have tried myself, of course, and noted that the real-time spectrum changed immensely with the slightest change of position of the instrument.

 

So what I am saying is this: play around to your heart's content, but don't draw too heavy conclusions from using analyzer software - it will probably only confirm what your ears are already telling you - in my case I could actually see that the fourth harmonic was higher than the fundamental on that note that sounded so awful.

Ah! Reed chambers, but we won't go there either...

 

/Henrik