PAPER HORN "BALMAIN"

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Inigo
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Re: PAPER HORN "BALMAIN"

Post by Inigo »

I suppose this inertial problem is common to all Balmain-like gramophones, including the original, despite the soft the motion would be along their tracks. It is also a problem with front mounted gramophones in which the soundbox must move the horn. If the inertia (mass) is too large, these low-freq needle deviations will move the diaphragm centre back and forth due to its comparatively higher compliance.
In the other hand, such mass is beneficial when transferring the needle vibrations to the diaphragm with no loss.
That's why the global solution is always a compromise between antagonistic principles.
In fact, just the continuous pressure of the spiral groove against the needle, which is what moves the assembly across the record towards the center, will always put the diaphragm in strain towards the front visible side. The diaphragm would be always out of its balanced central location. This could be balanced using a judicious small amount of tilting of the assembly towards the horn mouth. That's what someone else said, using gravity to compensate for the spiral advancing movement.
If besides that, the record is a "swinger" as you said, the diaphragm will be continuously pressed back and forth around its central static position.
Interesting matters.
This in itself couldn't be a great problem if the diaphragm stiffness is enough to counteract these forces with minimal strain. But the size of the air chamber behind the diaphragm would change, and so the sound obtained. But this is also a problem with the musical needle vibrations themselves, and so the size of the air chamber must be adjusted so it's average volume responds to the desired performance. A tunable soundbox as the emg addresses this problem by means of the adjustable back. But this adjustment also changes the pressure of the gaskets on the diaphragm edge, and so the effective diaphragm vibrating area. Then again, we have to achieve a balance between opposite factors, again a compromise.
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Re: PAPER HORN "BALMAIN"

Post by old country chemist »

THANK YOU, THANK YOU all, for your most interesting comments-and quite constructive too! Adrian Tuddenham looked in as a guest last evening, and read them all. He was very impressed with what you had to say. I just wish he would sign up himself, as he is a long standing gramophone record collector, with about 15,000 discs to his credit. He has done a lot of work in the past for the then "National Sound Archives" and the well known Peter Copeland, sadly no longer with us, was a good friend.
I now place on the forum the more advanced diagram of what he is thinking about. He does not think the bass will be affected, but the treble, as the "works" will be at the mouth end. may slightly be affected.
In the diagram, the NEEDLE DRAG RAIL is not pictured, and will be similar to the other two Balmain machines that have been made in the past.
Adrian has suggested that I make a mock up of the suggested bits and pieces and place them inside the horn of an Expert gramophone to see if there is any difference in reproduction, which I will do this week.
Track 7 (2).jpg

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Inigo
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Re: PAPER HORN "BALMAIN"

Post by Inigo »

What a marvel!
Mr. Tuddenham would be surely a great contribution to this forum!
The late Peter Copeland was a great guy. Once I was corresponding with him for recording dates, and he sent me the original txt files of all his articles on Historic Record, plus some excel files with data he collected for Spanish recordings. Good bless him!
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Re: PAPER HORN "BALMAIN"

Post by HMVDevotee »

Here is a solution; don't require the record's groove to do the work. Of course, in this case you would have to modify (or altogether abandon) the tone arm and make an adaption to support your soundbox of choice. I am wondering if there are other 78 feed-screw mechanisms that could be purchased and modified.

https://www.youtube.com/watch?v=5uAnv4EiVTQ

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Lucius1958
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Re: PAPER HORN "BALMAIN"

Post by Lucius1958 »

HMVDevotee wrote: Mon Mar 29, 2021 7:34 pm Here is a solution; don't require the record's groove to do the work. Of course, in this case you would have to modify (or altogether abandon) the tone arm and make an adaption to support your soundbox of choice. I am wondering if there are other 78 feed-screw mechanisms that could be purchased and modified.

https://www.youtube.com/watch?v=5uAnv4EiVTQ
I think there may be some issues with using a feed screw on 78s:

One is the inconsistency of thread pitches (especially on early discs). Systems like the early Sonoras had to provide some "play" in the soundbox, in order to overcome those differences - hence the infringement suit.

Another is the problem of run-out grooves: what happens when the needle hits those?

- Bill

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Inigo
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Re: PAPER HORN "BALMAIN"

Post by Inigo »

But altogether, here is a solution. And a question: that Sonora had a feed screw, or a sliding telescopic tube?
A sliding tube adapted to the soundbox neck could fit in a companion pipe inserted in the horn throat. The horn could be fixed in its longitudinal movement, and only the soundbox with its pipe would go sliding into the horn pipe. This way, the needle only had to move but a much smaller mass. The problem would be to get a perfect airtight sliding pipe that wouldn't block in its run across the record. A groove guide would be needed and a companion ridge in the pipes to avoid self rotation of the soundbox due to the needle drag.
Of course this would mean a cylindrical pipe prong of 6" at the narrow end of the horn. But we've read in Percy Wilson that such an enlargement of the sound path at the narrow end would do no harm to the sound. It could even help in stabilizing the sound wave train that comes from the soundbox into the horn.
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Re: PAPER HORN "BALMAIN"

Post by old country chemist »

6976+6977 (1).jpg
Here is the first picture of the machine which is being built. The picture shows the basic set-up, minus the motor box unit and soundbox.
I will be adding explanations to more photographs when I add them fairly soon. They have been written by Adrian Tuddenham, who can really
take the credit for thinking up, then manufacturing the mechanical side of this, what I call the "Neo Balmain" machine, even though it does not copy very closely most of Mr Balmain's ideas, The main similarity is the effect of "straight line amplification".
Mr Tuddenham is trying to enroll as a member of this gramophone forum, but is having much difficulty getting to grips with the system used, even though he is very well versed in computer technology, and has been for many years. So, I am copying his writings which he has so kindly sent me down as e mails. He has spent many hours both in thought and putting into practice his ideas. Granted, not all of the time does he get it right first time, but try and try again,and it all becomes second nature to him, (give him a pencil and a bit of paper, and he will work it out)as the theories seem to take form and work. I am sure not all of you on the forum will be in agreement with his designs, but we must congratulate him for producing something, (which we think will work well), and has not been copied from part projects by others. He is reasonably confident that this machine, when finished will work accurately, or as accurate as can be expected from a machine of this type. If there are any problems with the quality of reproduction, then I will hang my head low, as I constructed the horn, and may not have put the exponential theory, but the horn with over 34 layers of sugar bag paper, using over seven kilogrammes of strong paste, will at least be as acoustically "dead" as it can be.
I hope some of you will read this and find it as interesting as we have done as it has taken shape. Dear old Frank James is the chap who really got me into paper horn making. He was a great encourager amongst all his other qualities.

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Inigo
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Re: PAPER HORN "BALMAIN"

Post by Inigo »

Alastair, big hurrahs for you and for Adrian! We're eager to see your progress, and to watch and hear your tests!
Don't dismay even if the first sounds you get are not as expected... This machine, as did the commercial ones, will need fine adjustments and tuning, but we're sure you'll finally get an impressive sound with lots of 'presence' when the design is at its fine tuning stages.
Go ahead, gentlemen! :D
Inigo

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Re: PAPER HORN "BALMAIN"

Post by IainW »

Looking good, Adrian Tuddenham will be a great asset to the forum when he finally gets allowed in. As can been seen by Chunnys comment in the thread I had a similar problem earlier this year when I tried to join. There was a requirement for an answer but no question set if I remember correctly. It required the input of the forum administrator to manually let someone join. Maybe this is some kind of vetting process.
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Re: PAPER HORN "BALMAIN"

Post by epigramophone »

Adrian encountered the same problem, no verification question to answer.
I have contacted the Forum Administrator on his behalf and hope for a positive outcome.
The word "genius" is over used, but Adrian is the nearest I have ever met.

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