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Baffle Volume Reduction

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#1 Noel Ways

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Posted 25 September 2017 - 08:08 PM

For many years now I have played with a baffle pressed against the fretwork for lowering the intensity of the left, “bass” side my duet concertina.  This has worked well, but it did change the harmonics and nature of the sound to a noticeable (although acceptable) degree.

 

I have now inserted a different type of baffle that does not affect the harmonics (at least to my ear) but definitely lowers the volume.

 

It is a great and effective improvement.  Pictures follow.  What I did was to put a pressure reducing barrier between the bellows and the left side of the concertina plates.  The baffle “breaths” and allows the left side to sound, but with less pressure and therefore with less volume.  And since it is deeper in the concertina, away from the fretwork, the quality of the sound seems to be the same as if there were no baffle, but now just softer.

 

The pressure reducing barrier (good stock cardboard) is reinforced for wooden ribbing to prevent flexing when under pressure.  Also, there are a few dowels to keep it away from the reeds.

 

I am going to play it like this for several weeks, if I find that I might like the left side to be a little louder, I may apply one VERY small pin hole to allow more air to pass, and therefore increase the pressure/volume.  I could add small pin holes as necessary.

 

Such a simple insert, yet is as if I have a new and better instrument.  Definitely sounds more balanced and better !!

 

Click on pictures below to enlarge

 

Baffle_1.jpg

 

Baffle_2.jpg


Edited by Noel Ways, 25 September 2017 - 09:54 PM.


#2 Geoff Wooff

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Posted 26 September 2017 - 04:01 AM

This very interesting  Noel .

 

From your  picture  it looks as if you currently have  no  air holes  in the  cardboard....  so I assume air is passing around the edges  or the cardboard is somewhat  porous  ?



#3 Don Taylor

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Posted 26 September 2017 - 08:10 AM

Yes, very interesting and quite a novel solution, I think.  Good thinking!

 

In addition to Geoff's question:

 

Do you find the bass reeds harder or slower to start?  

 

In addition to reducing pressure on the LHS does this baffle/valve increase air pressure on the RHS?

 

Do you find that you get more effective time out of your bellows?


Edited by Don Taylor, 26 September 2017 - 08:16 AM.


#4 Noel Ways

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Posted 26 September 2017 - 12:01 PM

The small dowels press the baffle against the bellows frame.  In addition to keeping them away from the reeds, it also minimizes peripheral leakage.  So I imagine, peripheral leakage is minimal.  The cardboard stock is porous.  Before I choose the cardboard, I checked to make sure that air would pass, but pass with difficulty.

If the baffle creates more resistance, then the pressure and volume difference between the two sides would be greater.  If the baffle creates less resistance then the difference in the pressure and volume would be reduced.  Below is put together a hypothetical graph of what I imagine is happening.

Yes, the bass reeds are slower to sound if I use the same bellows pressure as I did before.  To compensate, I apply a little more bellows pressure, and the bass reeds sound; and the treble reeds sing with even greater intensity.  So, the greater the resistance, the greater the difference in volume of the two sides.

I mentioned that I will play it as is for awhile before making the baffle a little more porous.  I don't want to make a mistake, but I can see already that there will be a "sweet spot" where the volume difference between the left and right side will be optimal, at a particular acceptable bellows pressue.

 

 

Attached Files


Edited by Noel Ways, 27 September 2017 - 09:40 PM.


#5 Don Taylor

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Posted 26 September 2017 - 02:52 PM

Noel:

 

I am not familiar air permeable card stock. 

 

Is this something special? 

 

All of the paper and cardboard that I have to hand does not breathe air.



#6 Noel Ways

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Posted 27 September 2017 - 09:08 PM

Don,

The baffle came from normal fibrous card board
that I found in a print shop.  I saw it there and just
asked it I could have it

This stock is slightly permeable to air.  My test was to
put it up to my mouth and try to breathe through it.  Air
past very very slowly, and with great difficulty.  It is dense, indeed.  I was OK with
this because I figured that the large surface area would
compensate.  And further, I knew that the permeability could and would be
adjusted.

Just like the concertina reeds may be tuned by the manufacturer
after they are installed, I feel pressure likewise needs to be adjusted
once a duet concertina is assembled - at least these hybrids do!

With this type of "baffle" (I actually think this is the wrong term for
this); once the pressure is low on the left side, it is easy to increase
it.  One just wants to do this slowly, pinhole by pinhole., testing after
each perforation.

I can easily envision an adjustable pressure reducing baffle using
a slider or diaphragm-like system which would allow more or less
pressure depending upon its position.  I have been thinking about
this for a long time now

And ....  wouldn't be nice if this was adjustable from outside the
concertina !!  I can see it.  I just hope someone will do it.

 

 

PS, after more thought, I modified my graph above ... if interested
 


Edited by Noel Ways, 27 September 2017 - 09:48 PM.


#7 Rod

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Posted 27 September 2017 - 10:28 PM

Noel, Have your experiments been restricted solely to your cardboard version ? How about woven fabrics which are available in such a massive variety of differing versions.

#8 Noel Ways

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Posted 28 September 2017 - 09:43 AM

I have next to my computer here a roll or cork, and sheets of
felt purchased for pressure reduction purposes.  The felt is
way too porous.  The cork is promising, but I would need to get
thicker cork stock.

I think woven fabrics would be too porous unless they are
perhaps treated some way.  But I'm not sure what that would be.

Air is a funny thing.  Molecules are so small, and air so "fluid" like
that it will find and take advantage of any minute hole or passageway to go from
one side to another.  I think that is why Geoff above (comment #2)

was asking about air passing around the edges.  There may be more than I suspect.

I have also considered porous wood stock (but that would be difficult to insert),

and leather - the leather would need to be reinforced.
Nevertheless, the cardboard stock is working well and has

reduced the pressure/volume on the left side noticeably.  The next step is to incrementally
increase the pressure on the left side to correct level.  Click on graph below.

With cardboard stock, this is easy.

Attached Thumbnails

  • Graph3.JPG

Edited by Noel Ways, 28 September 2017 - 10:14 AM.


#9 Don Taylor

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Posted 28 September 2017 - 12:51 PM

deleted.

Edited by Don Taylor, 28 September 2017 - 01:01 PM.


#10 Anglo-Irishman

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Posted 28 September 2017 - 02:03 PM

Noel,

I note in the text of your graphic you say, "C - The ideal resistance that balances the bass and treble to the player's ear."

 

I would submit that what we should be aiming for is balancing the bass and treble to the listener's ear. The opinion is often voiced that the player's and the listener's perceptions of volume, balance, etc. of a concertina deviate. The distance the sound has to travel seems to have an effect, and no listener is goung to be as close to the concertina as the player is.

 

Just a thought.

 

Cheers,

John



#11 Geoff Wooff

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Posted 29 September 2017 - 01:40 AM

With regard  to the balance  as heard  by an audience... this might be  more difficult to quantify  as  much depends on    external factors , like room acoustics , position of listeners  etc. ,  but making  sound recordings  can  give an  un-biased  opinion  as to  the  relative   power of  each  side  of a  concertina.

 

I made some recordings  a few years ago, for  the 'Tune of the Month'  forum , on Duets  and I  noticed  a better volume balance on those recordings  than  I was experiencing whilst playing.  On a metal ended   Wheatstone MacCann  I did  shift  the microphone position  to slightly favour  the  right hand  keyboard, but on a  Wakker Hayden   I kept the  microphone  in a central position.  This was  with the  recording device (with built in mic)   at  reachable  arms length  and  monitoring the  sounds 'heard '  by  the machine  through headphones  whilst playing.  The  results of my crude recordings  can be heard on  Soundcloud  if anyone is interested.

 

I think  a  sound balancing device  is a fine idea  but will need to be  somewhat adjustable , from  outside  as  you  suggest Noel.  I come back to the word 'Duet'  and suggest  the original  idea  was to play  two  or more  melody lines  on the one box.....  If the player wishes to  make a chordal accompaniment   on the left  side to a single line  melody on the right... well,  some re-balancing  is called for.

 

I am quite surprised  that I find no evidence  of  a similar  air pressure  balancing device  in the Accordion world.  Though I am sure much work has been  done in this regard. Modern  accordions  tend to  have  less  voices (  reed banks)  on the left   probably due to  the use of amplification. In the old days  more volume was desirous  when trying to  fill a dance hall.


Edited by Geoff Wooff, 29 September 2017 - 02:58 AM.


#12 Rod

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Posted 29 September 2017 - 03:05 AM

Any problem arising from an overpowering balance from the left hand notes or chords on an Anglo can, to a certain extent, be adjusted by a delicate reduction in the duration of those notes or chords when it comes to interpreting the music. A staccato left hand chord can be a very satisfactory device.

#13 Anglo-Irishman

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Posted 29 September 2017 - 09:03 AM

Just to play the Devil's Advocate for a moment ...

 

What do you do about the notes in the overlap area of a duet when one side is baffled?

 

My medium-sized duet - a Crane 48-button - has 9 notes each present on both ends. And sometimes it's easier to use a low RH note as part of an accomaniment, or to use a high LH note as part of the melody. Baffling one end would mean that this kind of "borrowing" of notes between the hands would no longer be possible, because a given note would be loud one time and soft the next. 

 

Since the Anglo has been mentioned in this context, I would remind you that melody and accompaniment both skip from LH to RH all the time. I reckon a scale run going from baffled end to non-baffled end would be hard to get smooth, and a chord played partially in the LH and partially in the RH would tend to be unbalanced.

 

What do you hope to gain from the one-sided baffle? The capability to play a melody way up high on the RH and thick chords way down low on the LH at the same time?

 

Diabolically,

John



#14 Noel Ways

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Posted 29 September 2017 - 10:33 AM

Just to play the Devil's Advocate for a moment ...

 

What do you do about the notes in the overlap area of a duet when one side is baffled?

 

My medium-sized duet - a Crane 48-button - has 9 notes each present on both ends. And sometimes it's easier to use a low RH note as part of an accomaniment, or to use a high LH note as part of the melody. Baffling one end would mean that this kind of "borrowing" of notes between the hands would no longer be possible, because a given note would be loud one time and soft the next. 

 

Hopefully, by balancing, if the melody shifts from the right side to the left side, one may not notice.

The way my concertina has been, both the left and right sides are noticeably different.

The goal here is to bring the two sides of this hybrid together.

Also, I am not really sure that the word "baffle" is the right word,
although we have been using it freely here. 

I have been using this word as it is the only one I know. 

But a traditional baffle will change not only the quality of the sound (harmonics)

but the quantity of the sound (volume).

Here, the goal is to NOT affect the quality,

but rather the quantity (volume), by introducing a pressure reducing device.

 

I can appreciate that on your Crane Duet, the melody can shift from right to left side easily.

 

The owner of a high end concertina probalby never needs to give thought

to these issues.  Their duet is doing what we all expect duets to do.

But hybrids, at this point, in my opinion, need tweaking.  We are taking

accordian reeds and putting them in a box that is not an accordian.

 

I am very grateful for hybrids.  As one concertina maker mentioned at one

point, they may have prevented the concertina from going into extinction.

But I feel that this manufacturing route, at least for me, has created some issues that I

am now trying to resolve.


Edited by Noel Ways, 02 October 2017 - 05:39 PM.


#15 Noel Ways

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Posted 29 September 2017 - 10:41 AM

Any problem arising from an overpowering balance from the left hand notes or chords on an Anglo can, to a certain extent, be adjusted by a delicate reduction in the duration of those notes or chords when it comes to interpreting the music. A staccato left hand chord can be a very satisfactory device.

 

 

Yes.  And staccato on a duet works well so that the volume issues are not even noticed.

But the nature of a Hayden Duet is that it can also lend itself very well to chordal accompaniment
that is legato with two, sometimes more buttons, pressed at the same time. 

When one wants to do this, issues surface, and volume reduction comes to mind.


Edited by Noel Ways, 29 September 2017 - 04:04 PM.


#16 Don Taylor

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Posted 29 September 2017 - 12:58 PM

I also own a Peacock like Noel's and can attest to the imbalance between the left and right hand side volume.



#17 Anglo-Irishman

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Posted 30 September 2017 - 12:27 PM

The owner of a high end concertina probalby never needs to give thought

to these issues.  Their duet is doing what we all expect duets to do.

But hybrids, at this point, in my opinion, need tweaking.  We are taking

accordian reeds and putting them in a box that is not an accordian.

Devil's Advocate again:

 

It seems that now you're attributing this perceived imbalance, not to Duets as such, but to Hybrids as such. For over 20 years, I've been playing a hybrid Anglo, namely a metal-ended Stagi 30-button. I myself, my bandmates and our audiences seem to like the balance, and it records well.

 

Just recently, an ad hoc field recording of me playing an "english-style," i.e. harmonised melodic, solo arrangement of "Plaisir d'amour" was used as the background music for a professional video. Lots of "oom-pah-pah" and block chords, and also some use of the highest notes on the C-row. This is just the kind of arrangement that would suffer from imbalance between the hands, but It comes over perfectly balanced - nowhere does the melody vanish beneath the accompaniment. The recording was made with the single mic of a hand cam, so there could have been no tweaking of the balance in a mixer.

 

So Hybrids can be well balanced!

 

Caveat: as I said, I've been playing this particular Stagi hybrid for over 20 years, and "Plaisir d'amour" has been one of my party pieces for most of that time. So it may be that, over time, my arrangement has optimised itself to the capabilities of the instrument. However, I never felt the need to "expose" the melody by deliberately "shortening" or "thinning out" the accompaniment.

 

Try accompanying melodies that are played high up on the RH with chords that are high up on the LH; i.e. let the fingers of both hands move outwards or inwards in sync. Your hybrid may sound more balanced that way. If not, there may be a design flaw in your particular hybrid.

 

Cheers,

John






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