Acoustic lateral cutting heads

[maxigroove]

Has anybody had any luck with a homemade ACOUSTIC lateral cutting head design? I am scratchbuilding a cutting lathe but want to integrate an acoustic cutting head a-la pre 1925. Years ago (when i was an enthusiastic kid) i used an ordinary HMV gramophone soundbox in reverse and recorded with it. the results were very poor. Cant find much information on an acoustic recording soundbox except in the original Berliner and Johnson patents. Any help or links to video demonstrations much appreciated!

[Soulbear]

Hi There,
Check out Bens Posts on the Forum https://www.lathetrolls.com/viewtopic.php?t=4960
and Here https://www.youtube.com/channel/UCbCFXDC1A3cpuxwxKS-jb3A
Maybe this might help??
Regards Soulbear

[maxigroove]

Thanks for your reply. Yeh, he does some great work and i have watched lots of his videos. Unfortunately, all of these are "Hill and Dale" recordings and superb quality but i was hoping to achieve the same with a "lateral" acoustic cutting head on disc. Could be quite a challenge i think!

[emorritt]

For lateral acoustic recording you need a large glass diaphragm. These ranged in diameter from around 2 inches to about 3 inches. The "ring" that suspended the diaphragm and contained the recording mechanism held gaskets, the glass and a rocking "bridge" balanced on machined edges, very similar to the armature in a Presto cutter. This allowed free lateral movement of the cutting stylus when moved by vibrations of the diaphragm. Usually, there was a centered arm that was glued to the diaphragm, which was then joined to the vertical link to the bridge. This part was fairly thin and suspended by a pivot on the upper corner, which allowed the unit to be raised and lowered to the wax disc. The cutting stylus was pretty much the same as the old style steel cutting needles sold years ago.

The drawing of the Brock-Nannestad recorder that was used by Eldridge Johnson in the formative days of the Victor Talking Machine Company is shown in the patent linked below. The photo is from a European website from a university that was trying to re-create an early recording of Beethoven's 5th, which they did with some success. They constructed the recorder and an primitive lathe that would carry a thick wax disc, similar to the original days of acoustic recording.

https://i.ibb.co/syVcVj8/1.jpg

https://i.ibb.co/ydFqccK/Mechhead.jpg

They're relatively simple designs, which is why record companies guarded their recording secrets closely, because the technology was easily duplicated. The Sooy brothers that worked for Victor, designed and built their own recorders and if during a session they had to go to the bathroom, the recorder came off the lathe, went into a box they carried with them and their secrets went to the bathroom with them.

Float glass, which is available from several manufacturers is a good choice for such diaphragms. It's thin and responsive just like the originals. It might be a bit pricey for small quantities of 2 - 3 inch circles, but it can be had. This is the glass that is used for LCD/LED panel covers; the thin glass that protects the panel.

[dubcutter89]

The photo is from a European website from a university

...and you can read through all of it here:

http://journal.sciencemuseum.ac.uk/browse/issue-03/the-art-and-science-of-acoustic-recording/

Good luck!
Lukas

[markrob]

Have you seen the Gakken kit

https://www.juno.co.uk/products/gakken-premium-gramophone-kit-with-english-instructions/512847-01/

[maxigroove]

Thank you all for your great information. Berliner, Johnson, and the Gaisbergs were all pretty smart cookies! The results that were achieved at times were amazing considering they were pioneering lateral recording. If i can come anywhere near their results i would be more than happy, even though we have more knowledge, technologies and materials available to us now. BTW Emorritt, i did see the Beethoven's 5th article..lot of good info there and sort of nice that they could achieve a better recording in 1913 than they did in 2015!!

[emorritt]

As with lacquer discs, there is some 'black art' that is no longer known to modern experimenters. One that I read about was engineers spitting on the gaskets that held the diaphragm in place. Also, glass wasn't the only material used for diaphragms. Mica, rice paper, some metals, etc. gave different results, depending on the musical style being recorded. I used rice paper (from a 78 album sleeve) to make a cylinder recording of a banjo a few years ago for a demonstration; it sounded much louder and brighter than the mica that came with the recorder. They also used different shaped horns. Most people have seen this characture:

https://soundofthehound.com/2020/05/06/fred-gaisberg-records-the-great-caruso-and-kickstarts-the-modern-record-business-our-new-podcast-episode-out-today/

and wonder why the horn is square - well, it WAS. Caruso (or Signori Foghorni as he called himself in charactures) was drawing what he saw in the studio. Squared horns gave better results for tenor recordings, octagonal for soprano/alto recordings and in some cases, triangular for baritone/bass recordings. Has something to do with the length and size affecting the acoustic characteristic of the horn. For instruments and small group or orchestral recordings, different size conical horns were used. Horns were also made of different materials, metal, paper and even fabric and many were taped on the outside to damp resonances. Near the end of the acoustic era, rubberized fabric was the material of choice, since it wouldn't resonate easily.

Combine all this with the design and construction of the recorder and you get results similar to those from years ago. But figuring all this out would take a lot of experimentation and trial and error. I think EMI (or maybe a private collector) in the UK has a functioning Lindstrom lathe like those used back in the day:

https://www.youtube.com/watch?v=zbHBxjFxBbo

but for this recording, they used a lacquer on top of a wax disc that was made, but they couldn't get it to plate for molds. The lacquer produced a strange sounding record (these were available years ago as a "box set" including a VHS of the video, a CD and a pressed vinyl 78 of the recording) because lacquer is much harder, even when fresh, than wax. The 78 pressing is not good and far from what would have been made 100 years ago.