The Talking Machine Forum — For All Antique Phonographs & Recordings

Greetings all of you! -on the forum. How I have missed not making time to look into what is good in the gramophone and phonograph world!
Now, I am in the process of manufacturing a paper horn, using an old "Tannoy" speaker horn, which is fairly exponentially correct. I am at present on my 32nd layer ( one quarter of an inch thickness), of blue sugar bag paper, applied with strong modern wallpaper paste. For quite some time I have wanted a Mk8 machine, but being a Scotsman, I never see any at bargain price. As the horn will take some time to dry completely, I am sourcing some other bits that I require-sound arm, case, motor and handle, turntable, etc. I have a couple of soundboxes that will suffice I am sure. Trawling through some paperwork recently, I re-discovered Balmain's gramophone with an article by Percy Wilson, from 1926. The idea of a "new style" Balmain appeals to me, with no pretense of course to any form of originality, may require some thinking, but I also have not ruled out the Mk8 idea, which may be easier to make! The main problem with that is the exponential conduit under the motor board, which connects the horn to the tone arm. I thought of manufacturing this "plumbing" from two halves of hardwood, gouged out so as to produce the necessary reduction in diameter required. Perhaps one of you may have some measurements from an original conduit that they could place on the forum for me? I would be grateful.
I am, hopefully, posting a couple of pictures of the horn as it is at present.
All good wishes to you folks. It is still my favourite hobby-and that is after 56 years of collecting
Alastair Murray

Great Alastair!
All you are punching me from time to time, as I also had projects to build a poor man's EMG...
And others still less messing but more difficult to design and calculate. And these others are, number one, the best of all: to make a removable attachment to be simply inserted into the rectangular conical horn of my Aeolian Vocalion gramophone to convert it into an exponential horn, with the same size, i.e. not protruding outside (in principle) that improves the sound by means of a much longer sound conduit with slower flare increase ratio, until arriving to the mouth of the horn. It needs to have a rubber tube at the back which goes up into the back conical J connector at the throat of the horn. Then continues in a series of reentrant rectangular chambers (two rectangular conduits) that run back and forward inside the huge rectangular horn, finally going forward and opening to the real horn throat.
The truck is to make the rectangular conduits, narrower than the horn, with reflector panels at the ends, and a final reflector at the b back that seals itself (with silicone flanges at the borders) against the internal walls of the horn. It has to be removable from the front, and use part of the horn walls... I've made many drawings by heart, but haven't yet put the maths into it to calculate the transverse suitable sections.
The idea is to have an attachment at hand, kind of megaphone reentrant horn, that you insert into the horn and improves the response, getting rid of the horrible conical ringing tone we all know so well...
I should scan some of my drawings and put them herein for discussion and general fun and enjoyment!
I have measured the horn with plans to model it in 3D graphic software so I can measure transverse cross sections of the air passages, and give the right angles and dimensions to the reflectors and conduits, so to make it approach the best expo horn that can be fit into the poor metal horn.
Some day I will take my dirty pants and t-shirt, buy some wood, and try it.

An absolutely fascinating project. I look forward very much to reading and seeing more as things develop !

Hi Alastair,
I love your new project, in fact I actually thought of making an EMG clone, since I will never have one. Being creative is my kind of fun while being retired and then locked up with Covid. I recently posted a thread about people making their own machines from scratch using spare parts, etc. If you wouldn't mind posting your project on my thread in addition to this one, I would be grateful:
viewtopic.php?f=2&t=46794

It's looking good, Alastair! The Tannoy horn has the right shape and it is a great mold for it.

I'm not familiar with a Tannoy horn, but as Carlos said, the shape looks great...

That looks fabulous Alastair! Oh, please recreate the mercury-filled float baths...

Failing that, our mutual friend the illustrious Graham Rankin will have exact dimensions of the EMG internal conduit - he had a number of new ones cast some years ago.

(P.S. for anyone baffled by the remark about mercury baths, see the right-hand column of page 1 here: http://www.gramophonemuseum.com/images/ ... e-1973.pdf)

Mercury float baths...

Here is a slightly less dangerous way of achieving a similar result...............

Thank you Graham for posting the two colour pictures of the "Balmain" type machine, on the forum. Can you tell me the method that was used to allow the horn to slide along the track, please? The whole outfit looks very similar to what I have in mind, if I pursue this design. I know the first Balmain gramophone had the mercury baths, but as mercury metal is volatile at room temperatures, I feel I would be sticking my neck out trying that, even though I have an ample amount of mercury here. I see also that the table supporting the Balmain gramophone looks like a light foldable table. Surely with all the weight of the machine, plus the several pounds in weight of mercury, a heavier table would be have been required!
I spoke with Mr Adrian Tuddenham, an electronics expert yesterday about the making of this style of machine. He says one big problem would be when a record was a "swinger"-meaning the spindle hole was off centre. He mentioned that an electronic device could be used to alleviate this condition, changing side direction of the horn very fast, similar to the apparatus that he has successfully used on his own cylinder playing machine, when cylinders are out of true.