Strange grooves....

[phonodesbois]

The other day I bought a small French phonograph with hunting horn, a case of cylinders (brown wax and black ones), reproducer and recorder.
Most cylinders are playable except a few ones which have very, very large grooves and cannot be played with an usual cylinder reproducer.
Were they engraved with a dicta phone type machine?
Any idea on how such a recording was made?
Thanks for your input.
Jeff

[startgroove]

How about a photo of the entire cylinder, or some method of determining scale? Russie

[Lucius1958]

A dictaphone (considering the finer pitch of its thread) would likely have used a smaller cutting stylus than normal.

What's the pitch of the grooves on this cylinder?

Bill

[Edisone]

It looks to be beautifully recorded, with the grooves widely separated. You need to carefully count how many grooves per inch.

[edisonphonoworks]

Masters were recorded at a pitch of 971/3 TPI for two minute. I have an original master feed screw for an Edison master phonograph. Actually though looking closer, in the lower picture it looks like the grooves are too close together, going into the next one, what does it do when you play it? It could also be a sub master from a master mold, made at 100tpi, and being close together would result in it being about 103 grooves or so. What does the whole cylinder look like? Another scenario is that it was a hot day when they recorded the cylinder, and the cylinder was loose on the mandrel and slipped while being recorded? How does it play improperly? Might be historically significant.

[phonodesbois]

Shame on me! I just forgot to provide scaling information...
So, they are all standard cylinders as shown on a pic with 3 cylinders, the one in the middle being a normal Edison one. I don't know which company made the light brown wax cylinder (at left on the pic) and I'm pretty sure that the black one ( at right on the pic) is neither an Edison nor a Pathé.

I tried to count the grooves (and got an headache!) and would say it's about 55 per inch while a 2mn should have 100 grooves.

When tested with a floating horn, we can hear sounds (music and words) however it's not at the right speed and the reproducer is moving faster than the feedscrew.

Thanks for your help and good luck to the East coast collectors, shoveling the snow (could you ship some to Europe?)
Jeff

[VintageTechnologies]

I have never heard of a cylinder with such coarse threads, e.g. approximately 55 TPI. Perhaps it was recorded on a homemade or modified machine; it would not be hard for a machinist to cut a custom feedscrew for an Edison. But, *why* would someone do that?

I can think of two ways to play it: 1) Send it to Glen Sage at www.tinfoil.com to be transcribed. 2) Play it on a Puck machine that has no feedscrew.

Dictation records were cut at 150 TPI, if I recall correctly.

[Phototone]

It seems, in the first post, the person said he bought a "small french machine" with these cylinders. He may actually have a non-feed-screw machine.

[phonodesbois]

Well, the phono has a floating horn but also a feedscrew...
So, I will have to test the cylinders on a Puck or Pathé 0.
Still no clue on how the recording was made!
Jeff

[Chuck]

I find it also of interest a few of the things
which are revealed in the magnified picture of
the black cylinder. The groove pitch varies.

Look closely at this picture: From the extreme left
side we have first a series of gouges and pits indicating
that the recorder cutter bounced and dug in.
Then, to the right of those, there is a blank space, then
the recorded grooves start.

Notice the spaces between grooves. The "land".
Every 5th "land" is wider than the rest of them.
If we label the first wide "land" as "land 0" and start
counting grooves moving to the right as we count,
it can be seen that "lands" 1,2,3, and 4 are narrow
ones, then #5 is another wide one. Then 6,7,8,9 are
again narrow, followed by #10, which is again wide.

Seeing this pattern clearly in the enlarged photo
and then going back and looking at this record in
the photo with the other 3 records, one can pick out
the pattern, although it is not magnified enough to
get a count, but the pattern can be recognized.

Could it be that way back then someone was doing
some recording experiments using a very coarse feed?

It is indeed a worthy experiment to try, because
as we all know so well, using a feed of 100 TPI
for 2-minute cylinders is about the finest feed which
can be used. Even at the standard 100 TPI, there is
always a severe "echo-around" problem, simply because
the grooves are spaced so closely.

So, if the playback time of the cylinder was sacrificed
somewhat, and the feed widened out to some larger
pitch, there would reach a point where the recording could be as loud as desired, with absolutely no
echoing into the adjacent groove.

But, that was not good for business because everyone
wanted at least 2 minutes of time per record.
So they settled on 100 TPI, which is a compromise
between playing time and recording problems due
to "echo-around" in loud passages.

I'll bet that by the looks of that magnified picture
there is not any "echo-around" recorded on that black
cylinder!! Look at those lands! They are huge!

Chuck