Fast attacks and high accelaration of the stylys

[sifis1983]

Hi there!

While I'm searching the basic techniques that are used in mastering process of cutting lacquer (or vinyl or etc...) I have a query, that I can't find a solution in any article...

Let's say that you have a track that contains a lot of excessive attacks (e.g. on snare drum or maybe blips or meretricious clicks, which anyone can find in experimental genres of music).
This is means that the cutting stylus will make big accelerations causing mistracking problems in reproduction... Am I right?

So, how is this can solved in mastering process?
Some compression with slow attack time?

Any suggestions?

Thanks...

[sifis1983]

To be more specific in my query I show you what I've read:

From Hydrogenaudio:
"Acceleration limiting might be used on the vinyl master"

How is this "acceleration limiting" is achieved?

Thanks...

[concretecowboy71]

There is a good thread here that tallks about how the Nuemann acceleration limiter functions. It is basically a compressor that works at about 4k with a set attack and release. It will kill your top end if not used carefully.

I had a job a few months ago that had very aggresive xylophone parts and it caused a skip in the test pressing. I could watch the playback arm wiggle during those parts until it just jumped.

Like a lot of disc cutting, it takes a series of compromises to get a master that works on a physical level while maintaining the intent of the artist.

[Aussie0zborn]

Like a lot of disc cutting, it takes a series of compromises to get a master that works on a physical level while maintaining the intent of the artist.

Well said !!

[sifis1983]

Thank you for your reply..

That thread you told me it's amazing! I'm really impressed!

but, as a newbie to record cutting, a lot of queries born again in my mind!

So, generally, the most lathes and cutting heads works like neumann sx74?
Is there no external processing of the signal in order to limit the accelerations of the stylus? (before it sends at the lathe)...
or the most of the lathes does this limit internally?

Thanks again... and I'm sorry for my poor English.. I hope you understand

[concretecowboy71]

Each cutter has a slightly different set up. There are different generations of gear (amp racks, acceleration limiters...).

The limiters I use are in the amp rack itself (VG 74B), but that does not mean that a cutter could not modify or use another unit completely.

I cannot even speak for the guys that use Scully lathes. It seems like the possibility for personal customization on those units is endless!

I would not say that all cutterheads function like an SX74. There is just too many variations. I am sure there are members here who can speak to those differences much better than I can.

Since I work from a computer, sometimes I use a de-esser (which is really a compressor tailored for a specific use) to help with these problems, I have found that I can be a bit more aggressive with that before it messes up the top end of the master than the limiters in the lathe rack.

That being said, I never turn my limiters off, I set them at zero or very low for added protection for my cutterhead.

[Serif]

...
So, generally, the most lathes and cutting heads works like neumann sx74?

Basically, yes, but, in addition to the Alan Blumlein concept's 45 degree angle wall grooves...

http://www.aardvarkmastering.com/westrex.htm

http://en.wikipedia.org/wiki/Alan_Blumlein

...there's also the Ortofon approach, which uses a rocking bridge to see-saw the 45 degree motion to the stylus shank even though the drive and feedback coils are all vertically mounted at 0 degrees to each other / both pair(s), "Orthogonal" to the blank plate.

Is there no external processing of the signal in order to limit the accelerations of the stylus? (before it sends at the lathe)...
or the most of the lathes does this limit internally?

Indeed, the program treble is both filtered and (often) selectively limited in the console. Interestingly, if automated feed and depth signaling is happening with the cut, the advance (or, "preview") channels need not be treble-limited. Most high frequency limiters start at 2-4 k and go up from there in action, so it's not going to be quite significant to the thinking lathe's decision on how much it can make the feed de-expand. to result in frugal, but not stingy, groove-packing, since it is the low frequency modulations that take up extra wiggle-room, and they will still be happening at the wisely-chosen base pitch, but the treble, which takes up less wiggle-room than bass does when at the same input level, does so with more rapid wiggling. The issue there is the ability or not to play it back both in terms of the proposed "handshake" between the radius of curvature of the groove and target pickup stylus tip, and also the weight of the cartridge as it pertains to both ability to stay put over the moving groove but not have too much inertia and be thrown or lifted off, and similar concerns that can make fidelity a sort of ghost chase... like a mirage that forever recedes into unreachable mists, just ahead... Imagine having highest fidelity and strongest signal which is unplayable or which disables cutter heads from making music... Compromise is the only solution.

Of course, even though acceleration limiters, or "treble limiters," are for protecting the delicate head coil windings and for maintaining the speed limit of the groove modulation so that the pickup stylus won't be thrown out and go skating or be distorted in terms of tracing, de-essing is obviously an aesthetically-moderated form of distortion addition, in itself. The goal is to make the recording conventionally strong in level and possibly to correct for monitoring issues in the mixing session. If you don't mind making a quiet record which may approach objectionable noise floor levels from lacquer hiss, the treble content can be left brutal, even with the RIAA emphasis in the loop, but the playback amplification may not be appropriate to preclude howl-round at those elevated make up gain settings (? - You define, brutal, for yourself... I just wanted to say, howl-round ;0) and the clicks and pops from a pressing will be similarly elevated in amplification when playing back a very quiet record, yes?

Many of these high frequency limiters come with side-chain inputs that allow a control signal from the head coils to cause attenuation of high frequency to be automated so that it will happen only when the energy of cutting increases (treble has more energy requirements than bass). It would be possibly more effective than relying on the operator to chose an overly risky or overly "safe" setting. Dynamic modification is what is wanted. Extremely brief, natural or only rolled, treble and _some_ air response left in during less energetic moments is a big plus in helping create the illusion of better fidelity. Since it's _all_ illusory-orientated, anyway (electronic music reproduction for pleasure), there is no penalty for fooling the ears, so to speak. (:

Lathes are not really made for processing the audio signal. The Ortofon manual explains that the head connector and cabling should be thought of as an extension of the cutting amplifiers, rather than as part of the lathe. Lathe, as giant mic stand - only the mic isn't really a mic and the stand is more like a cross between a sewing machine and big tape recorder. The lathe will turn the table on which the Pyral is spinning. The lathe will move the carriage from right to left in order tangentially to guide the saddled head across the turn table, thereby allowing for a spiral to be scratched onto the surface of the captive "grandmere." It's up to the head coils, and therefore, the cutting amps, and therefore, the transfer console... rather than the lathe, to make the groove start or stop wiggling while the spiral is "going down."

Suction for chip removal and also for holding the blank securely to the table may be provided by the lathe's auxiliary equipment. But the only audio signal processing going on, inside, (to the advance signals) is not the kind which will later be heard, except to the extent that it allows the modulated program's recording neither to result in an overcut groove nor to waste space (since wasted space is, forcibly, wasted fidelity - the least distortion of the input signal that gets cut as a modulated groove is at the furthest distance from the spindle).




- Ty Wuh-Nahn