The Tedrow Tone Attenuator

[Bob Tedrow]

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

[Stephen Mills]

I guess I'm wrong, Bob, but I never previously thought of you as coy. Pray, tell us more.

 

Signed,

 

A Duet Player - need I say more.

[Michael Ducky Raley]

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

What happens if you leave the screws loose and rotate while playing?

[Bob Tedrow]

By removing the reed, adjusting the slide beneath the tone hole/reed vent,and then replacing the reed, one can vary the volume of air (not the pressure, which remains constant) that passes over the reed in each direction.

 

I made several empirical trials using the sound lever meter pictured, comparing the level of an adjacent and unadjusted reed vent to the level of a reed vent at 0, 25% 50% 75% and 90% attenuated.

 

I found that there is a measurable and proportional effect on the volume of a reed when the TTA is progressively closed.

 

Players who find that the strident tone/volume of a given reed or range of reeds overpowers other reeds when played together might find this device useful as it is fully adjustable by the end user.

 

 

Bob

[chris]

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

What happens if you leave the screws loose and rotate while playing?

 

You go dizzy

chris

[Jack Bradshaw]

Certainly a useful idea..but how to apply it to concertina reeds ?

 

Grommets ?

Edited May 15, 2009 by Jack Bradshaw

[SqeezerGeezer]

Shouldn't this be called a "Volume Attenuator"? Or does it alter the tone as well as the volume?

 

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

[Greg Jowaisas]

OK Bob, back to work!

 

Personally I like the "valve lizard head" with extended tongue, adjacent in the attenuator photos.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

( For the less visually imaginative: The mylar valve reinforcement strip capped at the base with a leather samper. although I wouldn't put it past Bob to build some surreptitious art into his fine instruments.)

 

Greg

Edited May 15, 2009 by Greg Jowaisas

[Bob Tedrow]

Shouldn't this be called a "Volume Attenuator"? Or does it alter the tone as well as the volume?

 

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

 

Perhaps volume attenuator would be a better choice but I was attracted to the alliteration

 

Bob

[pete]

Shouldn't this be called a "Volume Attenuator"? Or does it alter the tone as well as the volume?

 

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

 

Perhaps volume attenuator would be a better choice but I was attracted to the alliteration

 

Bob

Bobblareblocker...?

[ragtimer]

Please take a look at this device.

http://hmi.homewood.net/tedrowtoneattenuator/

Several comments, Bob:

 

This is a great advance for balancing the LH to RH volume of a Duet -- and that's one of your new Haydens in the photos!

 

Would the production version of your TTA be of thin metal? That would steal less volume from the reed chamber and reduce the odds of the draw reed hitting against the TTA plate.

 

A finicky owner adjusting his TTAs would grow to appreciate the ease of removal and long-wearing ruggedness of your Hex-head cap screws. Maybe he'd want an offset crank screwdriver like in your photos

 

Tedrow Volume Attenuator == TVA == hard to sell in Tennessee?

 

However -- some of us have an alternative version of your concept. Instead of individual air chokes on each reed, how about a single plate covering the entire reed pan, between the reeds and the bellows? This would be simpler, and would have the special advantage of restricting the volume more and more as more notes were added to a chord.

 

It could also have a slide vane with a lever sticking out toward the player, so the player could adjust it for oom-pah Duet playing (closed), or wide open for playing a single band part that wanders between left and right hands. Or anywhere in between. Granted, it would not fine-tune the volume of individual reeds.

 

Both schemes are acceptable only if they do not slow down the attack of the reed when the button is pressed.

 

BTW, Stephen Mills' avatar shows not just a Duet, but a Hayden -- and the two lower C# and D# buttons tell me where he got it. Good.)

--Mike K.

Edited May 16, 2009 by ragtimer

[Dirge]

This is a successful wind up, right? I can't see why any competent maker would need it, and your reputation suggests you are more than a little competent.

 

You hooked a few though, and the tripe about duets having a unique ability to drown out the melody with the accompaniment has resurfaced. A bad workman blames his tools...

[Leo]

Shouldn't this be called a "Volume Attenuator"? Or does it alter the tone as well as the volume?

 

Please take a look at this device.

 

http://hmi.homewood.net/tedrowtoneattenuator/

 

 

Perhaps volume attenuator would be a better choice but I was attracted to the alliteration

 

Bob

Bobblareblocker...?

 

Alliteration is fun:

Tedrows thunder taming & tempering tool

Roberts reliable reed racket reducing resource

Bobs blow balancing buffer board

 

Thanks

Leo

[drbones]

Avoiding the argument of drowning out the melody with the accompaniment, and assuming the possibility that it is indeed a problem for some individuals or instruments (so I’m obviously flying blind here), It seems to me the TTA would have to be nearly closed to have any effect at all on air flow since the hole through the action board to the reed pan has a much larger surface area than the space between the reed and the shoe. It may however soften the tone or reduce volume since it is covering the hole through which the sound travels.

Even then, it seems it would have more of an effect on the pull than on the push since it’s easier to push air through an opening (pressure) than it is to pull it (vacuum).

I would also worry about the slide becoming loose over time, starting to rattle or whistle thus turning the concertina into a woodwind.

And another thing, I would consider naming it the “Tedrow Adjustable Tone Attenuator Slide”. I just like the acronym.

[Dana Johnson]

Certainly a useful idea..but how to apply it to concertina reeds ?

 

Grommets ?

I find that concertina reeds benefit from holes that are the right size for the reeds involved ( there is enough latitude here ) This seems to vary between different instruments ( some do well with small pad holes while some need larger ones ) I don't know if it is reed /reed shoe vent design or chamber proportions that determines the sort of pad hole you need for the reed to speak at it's best, but holes that are restricted past a certain point in concertinas cause the reed to blow flat when played with much volume. There comes a size at which this no longer happens. Just about any pad hole has more area than the average anglo reed, and should let as much air pass as the reed itself, yet too small a pad hole has the same effect as a pad that doesn't lift sufficiently. Reeds with too large pad holes seem to be less clear sounding than when the hole is a little smaller. My basic impression is that there is an optimum size for each reed / chamber combo. The differences involved aren't enough to bother adjusting each hole, but I have gone from one pad hole size to three on my C/G's.

 

Perhaps with Accordion reeds there aren't the same restrictions, but I'd prefer to have the instrument with better sized reeds for the ones that are too powerful. I used to have problems with the notes around the low D on the C/G being too powerful to use as a drone accompaniment, and redesigned the reeds to blend better. I think I also worry about the sliding pieces in Bob's instrument becoming a source of buzzing at some frequency. Seems like the less bits involved the less there is to go wrong.

Dana

[Frank Edgley]

The problem I see is that it would work for a one time fix, but may cause another problem, depending how it is used. Dana referred to it: pitch alteration. I have found that the height which a pad raises affects pitch. Pad height has the same effect as the attenuator: it reduces the volume of air flowing through and past the reed. I have noticed up to a 2 cent difference in 1/64 th inch difference in pad clearance. I suspect that the attenuator would have a similar effect. However, it could be done and then a fine tuning performed once the desired volume was achieved. This would not be something you would constantly be changing. A similar effect could be achieved by adding another button damper under the button. I commend Bob on his efforts to create a better concertina by trying out new ideas.

[wim wakker]

I don’t want to ruin the party, but Bob reinvented an existing feature: the variable airflow slide.

 

The first instruments (free bass concert accordions) with a primitive adjustable slide system were produced in the 1930s. The slides were operated with stepped switches that closed the opening ¼, ½ , ¾ or all the way.

The most successful and best known instrument with a much more sophisticated air flow slide system was the Victoria SDG, named after Salvatore di Gesualdo, a professor of (classical) accordion at the Padua University (Italy) and one of the great baroque performers. His instrument was built in 1984 (I owned #2, built in ‘85). The SDG went for $24000 in 1985….

The SDG had small slides on the outside of the instrument, one for each ‘foot’ register (8,8’,4,16,2 2/3) plus a nullifier that closed all the slides. In addition to the slide system, it also had a ‘jalousia’, which basically is a baffle that can be opened and closed from the outside. Jalousias have been used since the early 1900s.

 

Both systems have a different function. The variable airflow slide allows the player to adjust the volume of selected reeds. For example, on a SDG, when using a switch consisting of 16 and 4 foot reeds, you can reduce the airflow to the 4 foot reeds in order to change the balance. Actually, I think that’s exactly what Bob meant, adjusting the volume of certain reeds to improve the balance of the instrument.

 

To mute one side of the instrument, you need a baffle or a more sophisticated jalousia. You cannot use an airflow reducer for this.

Both the earlier versions and the SDG have an aluminum slide system in the action board (sandwiched). Bob’s system will also work in the ‘empty’ chambers, but I wonder what he would do with the blocked chambers (the chambers for the higher notes have chamber reduction blocks).

 

The downside…

Unfortunately, there is a considerable downside to a reduced airflow by altering the shape of the air column. It causes a change in pitch and harmonics, not because of the amount of air that enters the chamber is less (it is not the same as a pad that doesn’t open all the way, or a slightly smaller/larger air hole), but the shape of the air column and the rate the camber is filled interfere with the 2nd part of the reed cycle (stage 3 and 4) (see ‘all about reeds’ on our site if you want more details). A reed chamber is an air reservoir in which the pressure should not exceed ability of the reed to move back. The change in air column and air flow rate prevents the reed to come to full swing, much like pitch bending on a harmonica. In spite of the large amounts of money invested in research, no one ever patented this system.

 

Wim Wakker

Concertina Connection Inc.

Wakker Concertinas

[Jim Albea]

To mute one side of the instrument, you need a baffle or a more sophisticated jalousia. You cannot use an airflow reducer for this.

 

Isn't a jalousia a variable "airflow reducer" for the whole side? If so, wouldn't a jalousia be useful to alleviate the sometimes-overpowering left side of duets?

Edited July 2, 2009 by Jim Albea