Reducing The Volume Of Selected Reeds

[Jody Kruskal]

I see. I'm sure we would all be interested in hearing the results of your interesting modification.

[Rod]

David Barnert's interpretation of my point relating to air distribution is spot on.

[BW77]

 

 

...a sustained low drone will rob higher notes of air...

Running out of air is not a problem, my problem is that the lowest notes on the LHS are too loud for what I want to play.

 

 

I don't think Ron was referring to "running out of air" when he said "rob higher notes of air," so much as actually making the higher notes quieter by diverting air to an easier route of escape from the bellows that has lower resistance (bigger holes) than the high notes.

 

There are several factors involved here. Don's primary problem was that the low range drone over-powers the high notes. A related more general "problem" may be that the accompaniment ( particularly lefthanded with Anglos and Duets) over-powers the melody at the RH.

 

Now...the actual sound amplitude (loudness) is depending on the degree of pressure difference over the reed slot. The *air flow* itself is not causing the sound amplitude but is a result from the pressure difference causing the flow. Thus the "air escape" as I understand it is not the issue.

If a high and a low note are sounding simultaneously they both give their respective amplitude according to the present pressure difference which will be the same for both ( the difference between athmospheric ( approximately) pressure and the pressure inside the bellows). If a high note is played first and a low later, or reverse, and the pressure is preserved the relation between the two is not changed BUT you will not HEAR the high note as well.... it is audibly "drowned" by the low one. There are more acoustical causes of this than the instrument construction... like the varying perception within the tone spectrum and masking of high notes by lower ones.

 

What Jody talked about is musically very important of course. By skilled balancing of note length and the overall balance between treble and bass range some of the "problems" may be reduced. Playing melody on the RH in its lower octave,( not the top octave) , is one method and playing melody in octaves is another. ( with a symphony orchestra you have 20 violins instead of one for instance)

 

Back to modifying the instrument several methods have been suggested apart from my "taping over the pad holes" concept. By that method or by reducing the efficient pad opening by thicker pads, or by stiffening the valves... what is in common likely is the reduction of pressure difference over the reed slot resulting in reduced sound amplitude firstly. Maybe some sound absorption is added. An interesting related issue as I mentioned before is how the tone character is changed too (if/when that happens) . Someone who has set up tone spectrometric analysis under lab conditions who is tempted to investigate the matter? Or has it been done before? My hypothesis is that overtone spectrum for a reed firstly varies with amplitude. This is a fairly common musical experience with squeezeboxes - is it not? Playing less loud makes the sound "mellower"....? But we always have to keep in mind that our perception of sound is a complex story.

[Anglo-Irishman]

 

But we always have to keep in mind that our perception of sound is a complex story.

 

Quite!

 

When I had got my newly-acquired Lachenal Crane/Triumph duet played in and familiarised myself with its "personality," I got the annoying feeling that the high G on the RH side (g'') sounded weak, and was getting drowned out by any lower harmonies that I played it against.

I checked for inhibited movement in the associated pad, for detritus in the reed or reed chamber, and a few other things, but found no anomalies.

 

Then, for a completely different reason, I recorded a piece of music on the Crane, using one mic pointed at the middle of the bellows. And lo and behold! the g'' could be heard quite clearly over the harmonies in the recording!

 

So can it be that these "loud, low" reeds and "high, quiet" reeds can be perceived as such only from the player's standpoint, and as far as an audience or a recording mic are concerned need no attention?

 

Question to those of you who have these perceived problems: Did you notice them yourselves, or were they pointed out to you by "educated" listeners?

 

Cheers,

John

[BW77]

 

 

But we always have to keep in mind that our perception of sound is a complex story.

 

" I got the annoying feeling that the high G on the RH side (g'') sounded weak, and was getting drowned out by any lower harmonies that I played it against.

 

Then, for a completely different reason, I recorded a piece of music on the Crane, using one mic pointed at the middle of the bellows. And lo and behold! the g'' could be heard quite clearly over the harmonies in the recording!

 

So can it be that these "loud, low" reeds and "high, quiet" reeds can be perceived as such only from the player's standpoint, and as far as an audience or a recording mic are concerned need no attention?

 

Yes, the sound, and particular effects as with this g" issue certainly can be perceived differently for the player, for an audience and for anyone listening to the same performance but recorded. The general loudness while listening and recording has influence. The distance to the sound source ( free reed sound is particularly influenced by distance because of air absorption of high overtones) is important. Although the sound radiation from a concertina is rather spherical there are definite concentration effects - you notice when sitting next to a concertina player...!!

Perception of volume from a fairly high note like your g" can be masked by influence from lower frequencies - a phenomenon which can be difficult to explore. Quite often I have also come across single notes/reeds that sound discretely awful for myself but not for others and it can be terribly annoying indeed.

[Don Taylor]

I have experimented with taping pad holes for a few days now and have abandoned the idea. Any noticeable amount of sound-level reduction also results in reeds being slow to speak, especially at low volume/bellows pressure. I really notice it when trying to play arpeggios.

 

In retrospect, this is pretty obvious as the reduced pad hole size also reduces the air flow and at low pressure there is not enough air to start the reed in a timely fashion.

Edited February 7, 2017 by Don Taylor

[Jody Kruskal]

Shucks Don. It seemed like such an easy fix, and one that is just as easy to undo, just take the tape off. Which is what you will be doing I guess.

 

I have no idea if it would work...

 

but what about reducing the chamber volume or reflection characteristics by adding some equally reversible material in a way that did not impede the swing of the reed? Little strips of tape or even thicker thin foam tape along the interior edges of the chamber for instance? That might reduce loudness in your too loud reeds, no?

 

Just a thought.

 

Here is another thought, though not so easy to do. My Jefferies has a few low reeds that have lead (I think it's lead) weights at the tips to bring the pitch down. These reeds are small, speak quite well and they are dramatically quieter than the full sized low reeds on my Dipper. If it's just a few notes that you are looking to get quieter, you could have a few custom reeds and reed shoes made for you. If it worked, switching out the old reeds for the new ones would be easy and again reversible.

Edited February 7, 2017 by Jody Kruskal

[BW77]

I have experimented with taping pad holes for a few days now and have abandoned the idea. Any noticeable amount of sound-level reduction also results in reeds being slow to speak, especially at low volume/bellows pressure. I really notice it when trying to play arpeggios.

 

In retrospect, this is pretty obvious as the reduced pad hole size also reduces the air flow and at low pressure there is not enough air to start the reed in a timely fashion.

As you say not entirely surprising although I have not had the same problem in those ( few) cases I have tried it (only Wheatstone englishes ) . Since your instrument as I understand has got accordion type reeds which are different and are mounted in another way maybe pressure and flow conditions have other influence regarding reed onset. Theoretically the experienced disadvantage experimentally can be treated by setting the reeds lower since this can make them start at lower pressure.

I'm afraid resetting of the reeds can be a bit trickier with this construction though and maybe not even advisable if it generally is good as it is.

The other methods choking the reeds probably will have similar effect concerning on-set at low pressure of course but if you have the patience why not try one or two notes only. Reducing the pad travel ( and thus the pad opening area ) I would guess has the same effect on the reeds but if you combine it with using larger and thicker pads maybe some (minor...) absorption takes place that reduces the volume a little.

Otherwise I guess what remains is again experimenting with a part "baffle" for the lower left side fretwork but like I said before the effect likely is not impressive.... but it is simple and harmless...

[BW77]

I have no idea if it would work, but what about reducing the chamber volume by adding some equally reversible material in a way that did not impede the swing of the reed?

 

Just a thought.

Jody, yes why not... every thought is good (until tried in practise). I have tried this also but firstly to explore the possible absorption of high overtones to make the tone mellower. I could hardly detect any result on tone however and I did not think so much about reed onset at the time.

BUT..maybe a reduction of chamber volume can compensate a little for the slower onset that the tape trick has caused with Don's instrument. Otherwise from experience we expect the sound to become louder with a smaller reed chamber, don't we? And that is not what Don wanted in the first place. Keep in mind the result from reduction of chamber volume on older style englishes by adding cork partitions simulating the routine using chamber partitions for all reeds that I believe started in the 1890s or so.

Anyway..it has to be tried to know....

(Beside the topic...generally speaking it seems to me as if this problem with balance between left and right side with large Duets and Anglos has been observed since long as I have seen quite a few instruments having much less opening area of the fretwork at the lower left side but if it actually helps much is a different story. A major reduction at the left side by less fretwork or a complete baffle definitely works.... but that doesn't help Don...)

[Don Taylor]

I am now trying a baffle made from EVA foam sheet about 3mm thick. I bought mine off eBay, but it is readily available from craft shops. It is very easy to work with and 'cheap as chips'.

 

Actually, I made a double baffle: one is full size and then there is another roughly half size over the lower reeds, so the lower reeds have 6mm of foam covering them and the upper reeds 3mm.

 

Initial results are promising, unlike my previous leather baffle it does not seem to muffle the sound - the reeds still sound bright and even the thirds still sound like thirds :-(. There is some sound level reduction.

 

But, I need to live with this for a week or two before I decide if I like it.

 

One curious thing occured with the first version of this baffle. I cut out a single large hole for the button area and this resulted in some sagging below the buttons. When I assembled the concertina I found that one of the reeds had a sustain effect! The sagging foam was gently pressing on the inner section of the lever arm so that when I released the button the pad came down slowly and the sound volume decayed just like on a piano with the sustain pedal depressed. It occurred to me that if this effect could be controlled then it would open up a whole new way of playing the concertina.

[BW77]

I am now trying a baffle made from EVA foam sheet about 3mm thick. I bought mine off eBay, but it is readily available from craft shops. It is very easy to work with and 'cheap as chips'.

 

Actually, I made a double baffle:..., so the lower reeds have 6mm of foam covering them and the upper reeds 3mm.

 

Initial results are promising, unlike my previous leather baffle it does not seem to muffle the sound - the reeds still sound bright and even the thirds still sound like thirds :-(. There is some sound level reduction.

 

Great!... sounds as if you are finally getting some positive results. Maybe the material you got is just the right for you.

I have tried quite a few but the space underneath the endplate often sets a limit. You seem to have better space since

you managed 6 mm stuffing. Anyway...if this setup turns out not being fully satisfactory I want to mention an alternative.

For general damping of sound *heavy* substances are effective and there are various asphalt sheets you may use to

make baffles from. I have tested a couple of variants that were available from retailers of motor car or audio equipment.

May be 2-5 mm thick and usually self adhesive. You can combine with some cardboard too.

[Don Taylor]

I tried EVA foam because I read somewhere that it is acoustically neutral - it is neither a high pass nor a low pass filter. It is the same stuff that the soft foam ear plugs are made of, the ones you use when working with power tools or going to rock concerts ...

[BW77]

Very good, no objection at all, just another idea thinking of the reported sustain effect...if the EVA foam became too thick after all...