History of lead-in and lead-out grooves?

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Bob Dillon
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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 29 May 2019 02:58

From Wikipedia :

"A subsidiary, Tri-Ergon Musik AG of Berlin, made commercial phonograph records for the German, French, Swedish and Danish markets from about 1928 to 1932. The records were advertised and sold as "Tri-Ergon Photo-Electro-Records [de]".

Guess that helps explain why I haven't run across one of these records (I'm pretty sure) in the U.S.A.

H. callahan
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Re: History of lead-in and lead-out grooves?

Post by H. callahan » 29 May 2019 03:24

It would be helpful if Phil Brown could join in, he surely could tell you about "photo-electro" recordings in the USA.
...

Seems like i cannot stop posting today, but i had a look at my very limited collection of shellacs. Most i have are electrical recorded and this one here i´m not sure its acoustic recorded, but due to the sound quality (low to non existent bass, overall low volume, no clear highs, coloration which sounds like a horn made of metal) i assume it to be an acoustic recording:
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Its not that good visible, but this record does not have a lead-in, just a raised and closed ring on the outside.
But it does have a lead-out:
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and as one can see this lead out is a (way) wider and deeper groove than the grooves containing the music. It looks like being cut by hand and could support my theory of lead-ins and -outs not being doable during the cutting process of an acoustic record - only added later to the cut.

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 29 May 2019 18:10

H. callahan wrote:
29 May 2019 02:28
Bob Dillon wrote:
29 May 2019 02:02
No problem about being at all rusty. Some of this old stuff isn't exactly the front page news.
You said it.

Comming back to the question of the TO, i have another idea about the missing lead-ins and lead-outs on acoustic records:

Making an acoustic recording (for to press shellac records of) is pretty tricky. The soundbox, let´s better say the recording box, at the end of the horn does feature a diaphragm made of very thin glass. So when you sing to loud into the horn you actually can brake the diaphragm - and then the recording has to be repeated.

The most pressing issue was always not to overcut the wax. Acoustical records depend entirely on the force of sound projected into the horn, no way to electronically modulate the signal. Too much sound energy and the cutting stylus cuts right through the groove wall and ruins the take.

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 29 May 2019 23:29

H. callahan wrote:
29 May 2019 03:24


and as one can see this lead out is a (way) wider and deeper groove than the grooves containing the music. It looks like being cut by hand and could support my theory of lead-ins and -outs not being doable during the cutting process of an acoustic record - only added later to the cut.
Yes, that is an acoustical record. I'd say ca. 1910.

I suppose it's possible that the recording engineer could have varied the depth of the cut "on the fly". I tend to doubt it was added later. I have early Victor acoustics that have very similar looking grooves.

Since we're diverting into all this stuff, here's a video of an actual acoustic recording lathe in action.
Right about the 1:00 mark you can see a wax recording biscuit. The warming oven is also shown. But it seems like they are using a lacquer disc to cut the actual take.

https://youtu.be/PcfZlub3meg

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Re: History of lead-in and lead-out grooves?

Post by H. callahan » 30 May 2019 07:57

No, i´m sorry, but recording too loud with an acoustic only is a problem for the glass diaphragm. You will break it when singing/playing too loud into the horn. Overcutting grooves always is a problem (also with electrical rec.), but they had variable pitch on acoustic machines, too. It was manual and had to be operated by the recording engineer depending on the music.
There was a great video about an acoustic recording made in Abbey Road Studios a few years ago, unfortunately i cannot find it right now.
Behind the recording engineer operating the cut, was standing another engineer looking at the sheet music. When a loud passage was to come within like two seconds he tapped the left shoulder of the recording engineer operating the cut, so he moves the recording box faster to the left to avoid overcut. When the loud passage was over he was tapped onto the right shoulder to decrease variable pitch of the recording box - and when a low volume passage was about to come he again was tapped onto the right shoulder to again decrease variable pitch.
So overcutting the grooves could be avoided - maximum recordable volume on acoustics is limited by the glass diaphragm, which also is the reason for acoustics being lower volume than electrical recordings. If overcutting the groove was a problem electricals should be lower volume than acoustics (or at least same volume), but its vice versa.
...

Concerning the lead out, i´m not sure if it is the result of varying the depth of the cut on the fly - because the fat groove starts right where the music ends/the lead out starts. The timing the engineer needed to exactly increase groove depth when the lead out starts had to be superhuman.
I´m very sure that this lead out has been added afterwards, even i think it was added after the (first) galvanic process.
Because if you look close, you will find that the lead-out also is a raised groove, like the ring on the outside of the record, and in the raise is the actual lead-out groove. Basically you cannot cut a raise on a positive (the matrix), but you could cut a raise on the first negative (first galvanic process, how do you call it, the mother?).
To have a raised groove on the matrix you basically had to add a wax-string, melt it onto the lead-out-area, of course it had to form a nice helix, and then cut a groove into the wax-helix - which wouldn´t be easy, while melting a nice wax-helix onto the lead-out-area would be even harder.

But when you got the first galvanic negative, you easily could cut a raised groove into the lead-out-area, but using a tool which does carve two grooves at once. You have to do so because on the negative every groove will be a raise, so you also have to cut a raise - but as you cannot cut a raise you have to cut two grooves which will form a single groove on the positive (shellac), but a raised one.

So i´m very sure that this lead-out was added later, even after the (first) galvanic process (at least).

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Re: History of lead-in and lead-out grooves?

Post by mvno_subscriber » 30 May 2019 12:18

H. callahan wrote:
30 May 2019 07:57
So i´m very sure that this lead-out was added later, even after the (first) galvanic process (at least).
Looking at an acoustic from around 1917, it could seem like the center loop is pre-made, with a little lead to connect the record and the loop (lower part of the record centre in the picture). Does this make sense?

http://arneheldal.no/data/images/forum_ ... G_6524.jpg

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Re: History of lead-in and lead-out grooves?

Post by H. callahan » 30 May 2019 13:58

Not sure about the loop being pre-made.

A recording engineer surely can estimate the time which can be recorded onto the disc, probably also depending on the piece of music - as the space between the grooves has to be varied depending on volume to maximize recording time.

But i doubt even an experienced recording engineer being able to estimate space needed for grooves down to like 1mm, so a pre-made loop could be cut. Therefore i assume this loop and lead being added after the cut. As this lead-out groove does not seem to be raised it may have been cut into the wax right after the recording - but cutting it before the music appears highly unlikely to me as this would create the risk of the last seconds of music overlapping the lead out.

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 30 May 2019 18:10

H. callahan wrote:
30 May 2019 07:57
No, i´m sorry, but recording too loud with an acoustic only is a problem for the glass diaphragm. You will break it when singing/playing too loud into the horn.
Hmm, well, any time I've come across old recollections from people involved in acoustical recordings, and the trials thereof, the issue of controlling the intensity of sound into the horn may come up. When it does, the reason stated has always been to avoid spoiling the wax, not breaking the recording diaphragm. Never heard a reference to that. But it can't not be acknowledged that it could have been an issue, those diaphragms were thin glass.

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Re: History of lead-in and lead-out grooves?

Post by mvno_subscriber » 30 May 2019 18:27

H. callahan wrote:
30 May 2019 13:58
Not sure about the loop being pre-made.

A recording engineer surely can estimate the time which can be recorded onto the disc, probably also depending on the piece of music - as the space between the grooves has to be varied depending on volume to maximize recording time.

But i doubt even an experienced recording engineer being able to estimate space needed for grooves down to like 1mm, so a pre-made loop could be cut. Therefore i assume this loop and lead being added after the cut. As this lead-out groove does not seem to be raised it may have been cut into the wax right after the recording - but cutting it before the music appears highly unlikely to me as this would create the risk of the last seconds of music overlapping the lead out.
I didn't mean that the recording engineer did it, but that the stamper itself had this lock groove, and a line was etched manually from the end of the recording to the lock groove. It could at least look like that on the record I pictured.

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 30 May 2019 18:39

Seems more likely that if they would do such a thing, it would be to the nickel plated master than the final stamper (s).

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 30 May 2019 19:17

This video might be of interest here : https://youtu.be/MWYHcFQ16Fs

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Re: History of lead-in and lead-out grooves?

Post by Coffee Phil » 31 May 2019 17:12

Hi Bob,

Interesting video. Thanks for linking it.

Phil
Bob Dillon wrote:
30 May 2019 19:17
This video might be of interest here : https://youtu.be/MWYHcFQ16Fs

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Re: History of lead-in and lead-out grooves?

Post by Bob Dillon » 01 Jun 2019 00:53

Coffee Phil wrote:
31 May 2019 17:12
Hi Bob,

Interesting video. Thanks for linking it.

Phil
Bob Dillon wrote:
30 May 2019 19:17
This video might be of interest here : https://youtu.be/MWYHcFQ16Fs
It is interesting, because we assume the lacquer that that eccentric groove is being cut to is itself cut from a tape or digital source. But back in olden times the direct cut lacquer or wax was what was the approved take. So if the cutting engineer were to f-up that little step... :D :byebye:

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Re: History of lead-in and lead-out grooves?

Post by H. callahan » 01 Jun 2019 07:33

Bob Dillon wrote:
30 May 2019 18:10
Hmm, well, any time I've come across old recollections from people involved in acoustical recordings, and the trials thereof, the issue of controlling the intensity of sound into the horn may come up. When it does, the reason stated has always been to avoid spoiling the wax, not breaking the recording diaphragm. Never heard a reference to that. But it can't not be acknowledged that it could have been an issue, those diaphragms were thin glass.
As far as i know there were many problems with acoustic recording and the sound quality of early shellcas. Also due to bad SNR (well, SNR being even worse than with later shellacs), so if they had been able to cut louder i´m sure they would have.
For example the first records released on shellac had such poor sound quality, a paper was given with each record describing what was recorded, resp. containing the text of the music/poem whatever.
Also to be able to make the first galvanig step, the wax surface has to be covered with somethin which will conduct electricity. Later/today they coat the matrix with a silver-looking fluid, maybe it even is chemically dissolved silver, but in the early days of shellac records they used some kind of powder which was conductive.
But the problem with such a powder is that it will increase microscopical roughness of the pressed groove, resulting in some kind of "shellac-roar", similar to the "vinyl-roar" on vinyls - basically the noise of friction between stylus and groove. And the greater the (microscopical) roughness of the groove, the greater the "roar".

Now when electrical recording for shellacs came up they had to switch from the powder to something finer, as esp. HF-modulations would not have been preserved on the stamper due to this powder being too rough. Also the overall copying (galvanic) and pressing process got more exact by no longer using this powder.
Now the surface noise on a shellac anyway isn´t low, but when using a plating process introducing another noise all one could do to overcome was to record louder.

Also think of the first soundboxes, where the "cantilever" was not suspended by a pivot (or even ball bearings) but being rather big+heavy itself and pressed by strong springs onto the soundboxes housing. Such a cantilever will not be able to follow the groove as freely, usually resulting in compression (low to non-existend bass, low highs) and overall reduced volume.

This means esp. in the early days there were quite some reasons to record as loud as possible and if they could have done so they would - but as far as i know they couldn´t because the glass diaphragm would break.

Because of that there usually was a recording engineer in the room with the musicians, giving hand signals when they were singing/playing too loud - but also when playing/singing too soft because of the poor SNR of early shellacs.


When the electrical recording came up they finally could record louder and they did. When i play an acoustic record with a medium needle it still is lower volume than playing some electrical recordings with a soft needle. And most electrical recordings also were cut into wax, so messing up the wax should not be the problem.
mvno_subscriber wrote:
30 May 2019 18:27
I didn't mean that the recording engineer did it, but that the stamper itself had this lock groove, and a line was etched manually from the end of the recording to the lock groove. It could at least look like that on the record I pictured.
The stamper is made from the wax-matrix and remember a stamper has a raised groove. So the manually etched line had to be a raised one - how you do that? - and the playing time of the recording had to be limited to match the pre-cut lead-out. Highly unlikely.

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Re: History of lead-in and lead-out grooves?

Post by H. callahan » 03 Jun 2019 14:14

Having made some research it seems that some recording boxes also had metal diaphragms. Now these couldn´t break (as easily) as glass diaphragms, but i couldn´t find out which material has been used most.

Anyway a reason for not cutting too loud i could think of might be distortion. The mechanical energy the cutting stylus of an acoustic recording box has is limited. At loud volume the cutting stylus has to cut more wax at the same time and at some point the cutting stylus should no longer be able to cut the modulation without loss into the groove - distortion would be the result.
An electric cutting head can drive the cutting stylus with (a lot) more energy to also cut loud signals without loss in modulation - so maybe they had to limit volume on acoustic recording to some limit to avoid distortion of the signal - though they also should have been able to just use bigger horns. The bigger the horn on a grammophone, the louder it will replay the record. This should work vice versa for recording, too. Then there was more energy for the cutting stylus, if the diaphragm was metal and cannot break (that easily), so i´m not sure if distortion of loud signals was that of a problem. But overlapping grooves should not have been a problem as there also was variable pitch on acoustic recording machines to avoid overlapping grooves.

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