View Full Version : Sound leakages before the track starts playing
magiccarpetride
12-10-2017, 00:01
On some records, when the cartridge drops to the lead-in groove, I can hear the 'phantom' split second opening sounds, which are quiet but still audible. After that, the music starts in full volume. I'm not sure what's causing this 'sneak preview' playback? Is it the worn out grooves? Or is it some pressing anomaly?
Light Dependant Resistor
12-10-2017, 01:54
On some records, when the cartridge drops to the lead-in groove, I can hear the 'phantom' split second opening sounds, which are quiet but still audible. After that, the music starts in full volume. I'm not sure what's causing this 'sneak preview' playback? Is it the worn out grooves? Or is it some pressing anomaly?
This also occurs on some CD's, for instance Creams Wheels of Fire,what is called print through, an artifact of analog transfer, can be heard on the track Spoonful in particular. Print through is explained here by the Audio Engineering Society
http://www.aes.org/aeshc/docs/3mtape/printthrough.pdf
................ Spoonful in particular......
Totally outstanding track, especially live. Sorry OP, back on piste.............
Firebottle
12-10-2017, 07:49
Sometimes known as pre-echo, as Chris says it is an artifact of the master tape; when wound on the reel the proximity of one circumference of the tape against another can lead to the signal magnetising the next layer slightly, this is the ghost image that you hear.
Nothing to do with the disc or pressing.
:)
Sometimes known as pre-echo, as Chris says it is an artifact of the master tape; when wound on the reel the proximity of one circumference of the tape against another can lead to the signal magnetising the next layer slightly, this is the ghost image that you hear.
Nothing to do with the disc or pressing.
:)
Not quite. When a record is cut, ideally the groove pitch should be constantly adjusted so that a loud musical signal (that is a large groove excursion) does not cause the vinyl to 'slew', whereby a faint copy is superimposed on the previous neighbouring groove. If this is not done properly it too is perceived as a pre-echo.
I also saw something like this is the film The Matrix. It was described as Deja Vu. It's when the machines change something.
Not quite. When a record is cut, ideally the groove pitch should be constantly adjusted so that a loud musical signal (that is a large groove excursion) does not cause the vinyl to 'slew', whereby a faint copy is superimposed on the previous neighbouring groove. If this is not done properly it too is perceived as a pre-echo.
Could you explain how information from one part of the groove gets into part of the groove it runs next to?
When the Master lacquer the cutter is running in from outside edge to center, therefor how does the sound get transferred into another part of the spriralling groove which has already
been cut after the cutter has moved on ?
Just wondered because it is not how I perceive that pre echo to get onto vinyl, has to be from the master tape as outlined above surely ?
Light Dependant Resistor
13-10-2017, 13:30
Could you explain how information from one part of the groove gets into part of the groove it runs next to?
When the Master lacquer is cut is the cutter not running in from outside edge to center, therefor how does the the sound get transferred into another part of the spriralling groove which has already
been cut after the cutter has moved on ?
Just wondered because it is not how I perceive that pre echo to get onto vinyl, has to be from the master tape as outlined above surely ?
Hi Chris
This You Tube https://www.youtube.com/watch?v=S8SKbxxsjOY shows there is a preview look at the master tape that can assist the cutting process,
Barry I think has revealed that the preview process might also in some circumstance faintly transfer to the cutting head. ( not an easy moment to get ones own head around ) Meaning the preview might just be being heard,
But the main reason of print through is tape storage as I explained, and Alan - Firebottle refined. A good mastering engineer when transferring the analog tape to say CD could choose to edit out the print through, but in some ways it is more original having it there I think.
When the record laquer is cut, a heated cutter is used to cut (or 'plough') the groove in the laquer material. In cutting the groove the material is not only cut in depth but the material is 'heaved' laterally to a small extent. Normally the cutting engineer will ensure that the groove spacing is such that a heavily modulated groove will not affect the previous neighbouring groove. But if the previous neighbouring groove is silent, such as the lead-in groove to a track, one will hear the effect of the heavily modulated groove.
Idlewithnodrive
13-10-2017, 19:42
When the record laquer is cut, a heated cutter is used to cut (or 'plough') the groove in the laquer material. In cutting the groove the material is not only cut in depth but the material is 'heaved' laterally to a small extent. Normally the cutting engineer will ensure that the groove spacing is such that a heavily modulated groove will not affect the previous neighbouring groove. But if the previous neighbouring groove is silent, such as the leadin groove to a track, one will hear the effect of the heavily modulated groove.
And that explanation explains it perfectly for me. Ever thought of being a Technical Author Barry ?
magiccarpetride
13-10-2017, 20:36
When the record laquer is cut, a heated cutter is used to cut (or 'plough') the groove in the laquer material. In cutting the groove the material is not only cut in depth but the material is 'heaved' laterally to a small extent. Normally the cutting engineer will ensure that the groove spacing is such that a heavily modulated groove will not affect the previous neighbouring groove. But if the previous neighbouring groove is silent, such as the leadin groove to a track, one will hear the effect of the heavily modulated groove.
But most of my LPs don't exhibit this 'pre-echo' when I let the stylus drop to the lead-in groove. So what's the difference then between those LPs that do and those that don't have this 'pre-echo'?
But most of my LPs don't exhibit this 'pre-echo' when I let the stylus drop to the lead-in groove. So what's the difference then between those LPs that do and those that don't have this 'pre-echo'?
I can only assume that the majority of your records don't start with a loud chord, or you play your records quietly. The great majority of my LPs do not suffer from pre-echo, but some do and it is definitely audible. You will only hear the pre-echo when the silent groove is one revolution away from the start of the loud-starting track.
I'll try and find some examples that you might also have.
magiccarpetride
13-10-2017, 20:54
I can only assume that the majority of your records don't start with a loud chord, or you play your records quietly. The great majority of my LPs do not suffer from pre-echo, but some do and it is definitely audible. You will only hear the pre-echo when the silent groove is one revolution away from the start of the loud-starting track.
I'll try and find some examples that you might also have.
Thanks. Some of my LPs with audible pre-echo sound quite loud before the opening salvo, some on the other hand sound quite feeble, barely audible. Is the pre-echo volume a function of how loud is the opening salvo?
Thanks. Some of my LPs with audible pre-echo sound quite loud before the opening salvo, some on the other hand sound quite feeble, barely audible. Is the pre-echo volume a function of how loud is the opening salvo?
Yes.
magiccarpetride
13-10-2017, 22:55
Yes.
You made me curious now. I am going to try and find an LP that opens with super loud chord, but the pre-echo is nowhere to be heard. Maybe such LP doesn't exist, but I think I have a faint recollection of hearing a few of those...
Photoguy1510
14-10-2017, 06:05
Think the quality controll has a lot to do with it. Older lp is more likely that it will shine through as the TT of the day was not as clean and sensitive as what we have today so no one knew to avoid it. Next will be masts production how fast could they turn out 100 000 lp's to the masses who dont listen to music just the sound from the boxes with the round things in them that vibrate. I try to find limited production/ reproduction runs they seem to sound better on my avarage TT. I dont have 60k to fork out plus im to deaf to ever warrant that.
Sent from my SM-G935F using Tapatalk
Infinitely Baffled
15-10-2017, 22:24
Where the pre-echo results from magnetic tape print-through, I presume this occurs throughout the whole length of the tape ie. each wind of the tape on the spool contaminates the adjacent wind by superimposing a faint copy of the musical information it carries? It is only in the case of the first wind that we can hear it, for the simple reason that the adjacent tape is blank?
I have to say I do not understand the explanation of how a pre-echo results from the operation of the cutting lathe. Why would the "heave" in the vinyl material which results from the cutting of the adjacent groove just happen to leave a sound which is identical to the music being cut? Surely it is more likely to be some sort of vague "negative image" of the activity in the neighbouring groove?
IB
I'm not convinced it's the cutting lathe which is responsible for some pre-echo. I suspect the stamper and pressures involved when the the vinyl is soft. Adjacent grooves being imprinted with a subtle echo.
http://www.pressingvinyl.co.uk/index.php/2015/03/causes-pre-echo-groove-echo/
Congrats Barry, nice to see an argument backed up with source material and an interesting read.
Not enough of this in my opinion, with urban legend/Chinese whispers being repeated over and over in many cases on the internet, without any reference to where it started.
Not withstanding that Tape Burn through is also a real thing, so one or both may be contributing on a case by case scenario.
Good information all round. :)
Congrats Barry, nice to see an argument backed up with source material and an interesting read.
Not enough of this in my opinion, with urban legend/Chinese whispers being repeated over and over in many cases on the internet, without any reference to where it started.
Not withstanding that Tape Burn through is also a real thing, so one or both may be contributing on a case by case scenario.
Good information all round. :)
Yes, I wasn't suggesting that vinyl 'heave' during laquer cutting was the sole source of pre-echo, but does contribute, especially when the record grooves are 'nested'. But tape 'print through' will also contribute, though tapes are usually stored 'tails out' to minimise the effect.
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